Dr Anne Yvonne

Guillou Anthropologist

"An alternative memory of the Khmer Rouge genocide : The dead of the mass graves and the land guardian spirits (neak ta)"

Introduction

Wars and revolution violently impacted upon the three countries of what was once French Indochina in the bipolar political and military context of the Cold War 1 . They were responsible for the massive destruction of infrastructures, social fabric and human lives, bringing deep social suffering and social fracture which are still perceptible. However, little attention has been paid to the way in which individuals perceived this destruction, gave meaning to it, and went through the ordeal of losing their relatives, their work, their property, and -in the case of Cambodia -the very meaning of being Khmer in a country where "Khmer have killed Khmer", as a widely used Cambodian saying puts it. This massive destruction has forced every society affected by it to think about the dialectic of break/continuity in its individual and collective lives 2 . The social memory and meaning of the 1 Anne-Christine Taylor's comments on my research programme gave me new insights which proved to be fruitful in the field. I am indebted to Michel Rethy Antelme and Olivier de Bernon for sharing their knowledge with me on various aspects of my research. An early version of this article was presented at the seminar of the Centre Asie du Sud-Est, Paris in November 2009 and I benefitted from the discussion with my colleagues. Thank you to Bénédicte Brac de la Perrière for her helpful commentaries on this article. I am also deeply grateful to David Chandler for the constructive comments he made on it and his words of encouragement. This research was funded by the Centre Asie du Sud-Est of the French National Center of Scientific Research (CNRS). 2 I have shown in another article that women are perceived as the strongest pillars of shattered Cambodian society. It is one of the reasons why prostitution and women's "immoral behaviour" is a big issue in Cambodia. See Anne Y. Guillou (2000), 'Promotion de la femme et sexualité conjugale en temps de sida. Le 'principe de coupure' chez les Cambodgiennes instruites', in Marie-Eve Blanc et Laurence Husson et Evelyne Micollier (eds.), Sociétés Asiatiques face au Sida, L'Harmattan, Paris, pp. 67-91 [Promotion of Women and conjugal Sexuality massive destruction has evolved at different times and in different groups and does not necessarily follow the political agreements decided by international diplomacy 3 . In this regard, the massive destruction carried out by the Khmer Rouge in Cambodia from 1975 to 1979 is not yet a piece of past history, since the "Khmer Rouge Tribunal" was only set up in recent years, while other forms of social memory have developed, such as commemoration by the Cambodian state, and the more informal peasant practices that I describe in this article.

The context of the research

The analysis that I present in this article is drawn from a research programme that I initiated in 2006. It aims to analyze the process of social recovery following the social disruptions caused by years of war, genocide and guerrilla warfare between the 1960s and the 1990s, as well as the meaning given to it by Cambodians of various backgrounds. I am trying to build up an "anthropology of traces" that all this violence have left on bodies, psyches, landscapes, and rituals by tracing the language that makes sense for the Cambodian people themselves. The majority of my fieldwork has been undertaken in the province of Pursat (Western Cambodia) in a village that I will call Kompong Trolach 4 from which I widened my inquiries to two communes in the district of Bakan 5 . When I began my work, I had decided not to ask direct questions about the Khmer Rouge regime and not to use any biographical methods in order to avoid the imposition of such ethical categories as genocide, violence, suffering and trauma. Instead I began my inquiries by asking questions about what seemed to be important local places, such as shrines of land spirits (អន ក , neak ta), monasteries, and confronted to the AIDS Epidemics]. 3 In his groundbreaking research on the cultural meaning of mass war deaths in Vietnam, Heonik Kwon shows how the Cold War has not been analyzed from the Asian people's point of view, but from that of Westerners, for most of whom the war remained an ideological one rather than a concrete bloody one. Heonik Kwon (2008), Ghosts of War in Vietnam, Cambridge University Press, Cambridge. 4 The name of the village has been changed in order to respect the anonymity of the people that I have interviewed. 5 I have selected this area partly because the province of Pursat experienced harsh treatment during the Democratic Kampuchea regime. It is also an area representative of the average Cambodian village, with a subsistence production of paddy cultivated in non irrigated rice fields by Khmer people. Khmer people represent more than ninety percent of the population of Cambodia. canals (waterways). I was soon convinced that it made sense in the context of local history dominated by the powerful presence of Grandfather Khleang Mueng, a sixteenth-century Khmer army general who had defeated a Siamese army and was later transformed into a land spirit protecting the area. In other words, I chose the idiom of the places in order to encourage people to talk about their stories. The ethnographic information I gathered made me understand that there were special links among some stones, some trees, some objects, some land spirits, some dead of the Khmer Rouge mass graves, and some human beings. They were related through a circulating energy called បរមី (from Sanskrit "pāramī, pronounced boromey). This popular religious system has not yet been documented as such, although there are a few publications on separate elements of this system such as Theravadin Buddhist practices 6 and the worship of various spirits such as neak ta 7 .

Through my description of the treatment of the dead in the Khmer Rouge mass graves and killing fields, I will show how the Khmer popular religious system is instrumental in forging a memory of those who died under the Pol Pot regime. Democratic Kampuchea produced thousands of killing fields where corpses were simply abandoned. In other places like health centres, detention camps or places of execution, mass graves were dug nearby and corpses thrown in 8 . The district of Bakan contains many such places because the province of Pursat suffered very badly at that time. According to David Chandler "the worst conditions of 6 Among the most important publications using different approaches are Adhémard Leclère (1899), Le Bouddhisme au Cambodge, Ernest Leroux Publish., Paris; François Bizot's four volumes of the series Recherche sur le Bouddhisme Khmer (1976-1989), Paris, Publications de l'Ecole Française d'Extrême-Orient; Olivier de Bernon (2000), 'Le rituel de la 'grande probation annuelle' des religieux du Cambodge (mahaeparivaesakamma)', Bulletin de l'Ecole Française d'Extrême-Orient, Vol. 87, N°2, pp. 473-510; John Marston and Elizabeth Guthrie (eds.), Cambodian Buddhism, History and New Religious Movements (2004), University of Hawai'i Press, Honolulu; Ian Harris (2005), Cambodian Buddhism: History and Practice, University of Hawai'i Press, Honolulu. 7 The most important contributions are those of Eveline Porée-Maspero's three volumes, Etude sur les Rites Agraires des Cambodgiens (1952-1964-1969), Mouton, Paris/The Hague; Choulean Ang has written numerous articles on many aspects of the religious popular beliefs. See in particular Choulean Ang (1986) all were probably in dambon [Khmer Rouge district] 2 and 6 in Pursat 9 , where new people were made to carve villages out of malarial forest. In these zones, deaths from starvation, disease, and overwork were frequent, while CPK cadre suffered from regional purges in 1976 and 1978. They were replaced, here and in the northwest, by cadre brought in from the Southwestern Zone, the area controlled by Ta Mok […]" 10 . Moreover, after the rebellion of the Eastern Zone cadres in 1978, thousands of people from Svay Rieng and Prey Veng were sent to Pursat and killed. Many of them wore blue scarves (krama) and some villagers I interviewed remembered the fear and pity they felt when they met those evacuees 11 .

Nowadays, when an uninformed visitor rides his/her motorcycle through the sunny paddy fields with their typical sugar palms, the cool chamcar (cultivated fields) and the quiet villages, he/she cannot be aware that a few meters from the path, behind a tree, lies a well full of human bones or a field named "Svay Rieng" because hundreds of deportees from the Eastern provinces, including newborn babies and pregnant women, were slaughtered there one night in 1978.

Before returning to the village of Kompaeng Svay and its haunted rice fields, I will analyze two other forms of justice and memory set up at the international level with the United Nations-sponsored Khmer Rouge court, and at the national level with the state remembrance policy. 9 My own field research takes place in former Khmer Rouge districts (dambon) 2 and 7. 10 David P. Chandler (1991), The Tragedy of Cambodian History. Politics, War, and Revolution since 1945, Yale University Press, New Haven and London, p. 269. See also the detailed description of daily life in dombon 2 and 7 by Michael Vickery (1984), Cambodia: 1975-1982, South End Press, Boston, pp. 114-118. 11 Ben Kiernan has analyzed the distribution of blue scarves to evacuees from the East as a step in their planned elimination. However, Steven Heder convincingly argues that the distribution was not planned in order to make the people from the East more recognizable, although he agrees with the fact that the Pol Pot regime, "inspired by a modernizing ideology with genocidal potentialities, realizes those potentialities through a set of genocidal practices". See Ben Kiernan (1996), The Pol Pot Regime. Race, Power, and Genocide in Cambodia under the Khmer Rouge, 1975-1979, Yale University Press, New Haven and London, pp. 392-416; Steven Heder (1997),

Misunderstanding and discrepancy surrounding the Khmer Rouge Court

The "Khmer Rouge Tribunal"

The "Khmer Rouge Tribunal" was set up in 2007 when five of the prominent leaders of Democratic Kampuchea (among those who are still alive 12 ) were arrested and held in preventive detention 13 . This raised once more issues of justice and memory, some thirty years after the fall of the Khmer Rouge regime. This was a significant step after ten years of negotiation between the Cambodian government and the United Nations regarding the creation of a mixed court 14 . As an outcome of these debates, the Extraordinary Chambers in the Courts of Cambodia (E.C.C.C.) were specially created for the trial and may "fit into [the] 'second generation' of international criminal justice mechanism" 15 which gives more importance to the law of the host country than the former ad hoc international tribunals in former Yugoslavia and Rwanda. Although the running of such a court is not an easy task, the first case was judged in May 2010 : Duch, chief of the biggest political prison where thousands of people were tortured and killed, was found guilty of crimes against humanity and sentenced to thirty-five years in prison 16 . This Court will try at least four other leaders charged of crimes against humanity and/or war crimes perpetrated between April 1975 and January 1979. These crimes were perpetrated under the radical communist regime inspired by Mao, his radical entourage and his agrarian state doctrine. The Khmer Communists dreamt of achieving what they called a "super great leap forward" that would boost Cambodia to an economic and political level of 12 Pol Pot, the so-called brother Number One died in 1998. Ta Mok and Ke Pauk also passed away in the 1990s and 2000s. 13 Namely, Ieng Sary, Ieng Thirith (Khieu Thirith), Kaing Kek Eav (alias Duch), Khieu Samphan and Nuon Chea. 14 The two Cambodian prime ministers Hun Sen and Norodom Ranariddh asked for the help of the United Nations for the settlement of a tribunal in 1997. The law creating the Extraordinary chambers in the courts of Cambodia was adopted by the Cambodian Parliament in 2001 and was promulgated by the King in 2004. See David Boyle (2001), 'Une juridiction hybride chargée de juger les Khmers Rouges ', Droits Fondamentaux, N°1, pp. 213-227. 15 John D. Ciorciari (2006), 'Introduction', in The Khmer Rouge Tribunal, in John D. Ciorciari (ed.), Documentation Center of Cambodia, Phnom Penh, p. 18. 16 The judges reduced the sentence by five years because he had been held illegally by the Cambodian government in the 1990s, and reduced it by a further eleven years for time already served behind bars. sophistication equivalent to that of the Angkor era (eighth to fifteenth century), when Cambodia was a powerful empire. This Utopia led to a totalitarian organization whose chiefs ordered the deportation of hundreds of thousands of people sent to work without compensation in the agricultural sector. The revolution sought to destroy family ties, religious practices, and the education and health systems, while trying to create new institutions like health centres and (in some cases) schools, but with little success. The policies of Democratic Kampuchea (DK) led to the deaths of at least one million seven hundred thousand people who were executed (the military of the Lon Nol regime were particularly targeted), starved, overworked or died of untreated diseases and other abuses, as well as internal purges among the Khmer Rouge cadres themselves. One million seven hundred thousand represented a quarter of the Cambodian population in 1975. Nowadays, one can still read advertisements in newspapers, on posters or via the Internet, written by survivors looking for their family members who disappeared over thirty years ago. In the Cambodian paddy-fields and bush, hundreds of thousands of human remains are still scattered or piled in mass graves, without having had a proper funeral. Many people still do not know where their loved ones died.

Discrepancies

At a time when the eyes of the world are focused on the trials of the Cambodian communist leaders in Phnom Penh, some journalists have reported that the Cambodians' opinion regarding this trial is not clear-cut. Some well informed urban people criticize the high cost of this United Nations-sponsored court while rural people feel no strong interest in this trial. Moreover, most of the genocide memorials built by the Cambodian government in the 1980s were no longer looked after in the 1990s and they have now disappeared or are in very poor condition. A few of them were repaired in the 2000s for various reasons related to tourism, pressures from the Cambodian diaspora and local political interest (described below). This seeming discrepancy between worldwide interest in the Khmer Rouge trial and the lack of interest expressed inside Cambodia itself has raised questions among Western observers. Some have written that the Cambodian attitude should be understood in reference to the Buddhist philosophy of detachment. Others have said that this is due to the attitude of some prominent Cambodian political leaders (including Prime Minister Hun Sen) who were themselves former Khmer Rouge cadres and wanted the past to be forgotten and witnesses to remain silent. I woud argue that these explanations do not give a comprehensive picture of the many misunderstandings surrounding the Khmer Rouge Trial regarding post-genocide justice, compensation and bereavement. Indeed, all of these misunderstandings have occurred since 1975 due to discrepancies and gaps of various kinds between the actions and perceptions of various actors such as the United Nations and the Western countries, the Cambodian governments and their allies, and the Cambodian people, including the villagers (who represent more than seventy-five per cent of the Cambodian population). These gaps are related to the timing of the trial, the level of charges against the perpetrators, the perceptions of suffering and the construction of memories of the genocide. In particular, as we shall see, while the United Nations-sponsored trial was organized some thirty years after the genocide, other local systems of justice and remembrance had already been set up.

In what follows I will focus on the Cambodian peasants. Although they suffered greatly during the Khmer Rouge regime17 , they have aroused little interest among journalists (apart from the villagers living in Northern Cambodia ruled by the former Khmer Rouge guerrilla, most of the information came from interviews with the Cambodian diaspora and the city dwellers) or among researchers. The latter have mostly conducted research on the power structure of Democratic Kampuchea while the process of the internalization of the Khmer Rouge terror has been described through biographies and autobiographies. Only a few examples of field work have dealt with the impact of the Pol Pot regime on the social life of the peasants and their own perception of the genocide and its aftermath 18 .

As a Khmer-speaking anthropologist involved in research on Cambodians since 1986, I have gathered data in various circumstances showing that the Cambodians have not remained silent, unconcerned or reluctant to try the Khmer Rouge leaders, but have instead developed, decades before the trial, their own "relief device" from social suffering and their own sophisticated "memory device" interlinked with the traditional Khmer religious system. This has been working silently for thirty years now, far from the city and the journalists. In describing here a part of this "relief device", I do not mean that the "Khmer Rouge Court" is unnecessary because the Khmer people have created their own resiliency system. The work of the Court is an important part of the construction of international post-genocide justice in a globalized world. However, I suggest that the Tribunal has been used as a part of what Michel Foucault would have called the "biopolitics of international justice". In other words, many narratives of the Tribunal have focused on the "healing" of the victims as its most important role, as if post-genocide justice were foremost a matter of health. By doing so, the accounts given in many areas of the Tribunal have tended to impose an overall pattern of what social suffering should be and how it should be expressed and relieved, by using the idioms of "trauma" and "post-traumatic stress disorder" as their only models. The ideology underlying the overuse of the psychiatric scheme helps to reinforce the marginalization of small societies like Cambodia in the globalized world by producing a particular image of them: not only did the Cambodians slaughter each other during an "auto-genocide" 19 , not only did they suffer from mental illness caused by trauma but they also remained unconcerned and passive after the genocide. This ideological pattern in turn aims to make the proliferation of so-called humanitarian organizations in Cambodia acceptable by spreading the idea that Cambodians cannot help themselves or be treated as responsible citizens.

Asian Studies, Vol. 37, N° 3, pp. 527-546; Eve Monique Zucker (2008), 'In the absence of elders: chaos and moral order in the aftermath of the Khmer Rouge' in Alexandra Kent and David Chandler (eds.), People of Virtue: Reconfiguring Religion, Power and Moral Order in Cambodia Today,Nordic Institute of Asian Studies,Copenhagen, See the criticism of the use of the word "auto-genocide" by Richard Rechtmann (2001), 'Altérité suspecte et identité coupable dans la diaspora cambodgienne', in Jean-Christophe Attias et Esher Benbassa (eds.), La Haine de Soi: Difficiles Identités, Ed. Complexes, Brussels, pp. 173-188.

Taking care of the dead of the state memorials

The state remembrance policy Democratic Kampuchea was overthrown in January 1979 by its former Communist allies from Vietnam. Cambodia was then in chaos. The new Cambodian government set up under the supervision of the Vietnamese quickly made efforts to build up national justice and memory. Pol Pot and Ieng Sary were sentenced to death in absentia by the Revolutionary People's Court 20 while people in the countryside were forbidden to take the law into their own hands by punishing some of the local Khmer Rouge cadres (but not all of them) who had been cruel. A museum was set up inside the main political detention camp (S-21) with the help of East European museography specialists. The new People's Republic of Kampuchea (PRK) also dealt with the numerous mass graves, killing fields and individual corpses scattered all over the country.

Local authorities were urged to put the human remains together and place them in boneyards built in each commune (khum). Villagers helped in picking skulls and "long bones" (ឆ្អ ឹ ងែវង) from the nearby villages, although in some places the human remains were just left in a pile in the bush under a big tree or left in ponds or wells. These boneyards and memorials (called ស្ដ ូ ប (sdop from the word stupa) or ងសង់ (sang song which means "to build" 21 )

were more or less sophisticated depending on the amount of money available locally, since the country was then enduring extreme poverty. (khum) of Pursat and visited the killing sites. They helped in organizing the 7 January Liberation Day and the 20 May celebrations. The former was the anniversary of the overthrow of the Khmer Rouge regime while the latter was the so-called Day of Anger (ទិ ចងកំ ហឹ ង, tivea chang komheung) which commemorated the crimes of the Khmer Rouge. Every year, an official ceremony was held in front of the memorials. Although

Buddhism was scarcely tolerated in the 1980s, monks from the nearby monasteries were invited to pray for the dead and perform a bangskol (បង ុ កូ ល). In the present popular perception common in mainland South East Asian Theravadin countries 22 , this means that laymen make offerings to the monks who, in turn, by chanting special prayers, are able to send the merit obtained to the dead. The celebration was also organized for political and propaganda purposes: at that time, the Vietnamese protectorate over Cambodia was criticized inside as well as outside the country and the government made efforts to explain the presence of over 100,000 Vietnamese soldiers and political advisors by insisting on crimes committed by the "Pol Pot clique" and the danger they still represented if the survivors were not protected by the Vietnamese. The human remains then became the best proof of the genocide and therefore a symbol of the legitimacy of the newly-installed Vietnamese-backed government. In the province of Pursat for example, I was told that the authorities had sometimes "borrowed" the bones from village memorials in order to organize bigger ceremonies at the provincial level 23 .

Then, in the early 1990s, state memorials were gradually neglected by the officials and The second was that keeping the bones would bring back the war". As for the peasants' perceptions, these memorials were seen as state-sponsored commemoration devices and as such, they did not feel concerned by them. However, the celebration of the Day of Anger was still performed but it was given a new political colour, "downgraded" to the status of a partysponsored event that now bears the name of េគរពវ ិញ ញ ណកខ ន្ ◌ធ (Ceremony of Paying are performed on public premises such as schools.

The villagers take over

After the government stopped looking after the memorials, villagers began to take care of the dead kept in some of them. Let us listen to the account given by M. Sophon. He is a peasant in his forties, owning a house near a memorial of this kind (Kropeu Ro village, khum of Snam Preah).

" However, the fear was not general as many people point out that they used to come across corpses during the Pol Pot regime and even sleep near them or among them in the forest.

"Hungry people are afraid of nothing, they just think about eating and surviving", an old woman told me when I asked her if she was afraid of these ghosts. Some young people recall playing with the skulls of the dead in the bush when they were children in the early 1980s, when human remains scattered in fields were a familiar sight 29 . M. Sophon's interview suggests that after the trauma of the Khmer Rouge regime, people gradually became increasingly involved in making a living and rebuilding their lives. Rice fields and fruit trees were planted again over the mass graves, which symbolically meant that the life cycle was starting again. A former village chief told me that he created a new market near the Snam Preah memorial so as to prevent ghosts from bothering the living, because ghosts prefer remote, dark and uninhabited places (there is still no electricity or roads in much of the Cambodian countryside and in the 1980s, there were only bicycles). 27 The narrative of people losing their hair after encountering spirits, particularly priey (្រពយ) which share some characteristics of the ap, is not uncommon. See Choulean Ang, Les êtres surnaturels, op. cit., p. 129, n. 309). 28 In Khmer language, khmaoch (េខម ច) means "corpse", "ghost" and some other kinds of spirits which may interact with human beings. The dead are always liable to come in contact with the living hence the superimposition of the meanings of khmaoch. 29 Another informant told me that these ghosts were too weak to be harmful because they had nothing to eat.

Family funeral rituals

At the same time, hundreds of thousands of funeral rituals were performed by the families whose relatives had died during the Pol Pot regime. These dead were not the usual dead : their deaths were "bad" and collective and their corpses were abandoned in unknown places, away from home. Were the funeral rituals performed different from those usually used on more "normal" occasions? Usually the rituals performed during "normal death" begin with religious assistance to the person who has died by reminding him/her of the principle of impermanence and helping him/her to leave the material world 30 . These rituals were simplified in the early 1980s when Buddhism was scarcely tolerated by the PRK and when very few monks were ordained. The main element of change in the funeral rituals of people who died under Democratic Kampuchea regime was the impossibility of performing the bangskol ritual (បង ុ កូ ល) in accordance with the tradition of the non-reformed mahānikāy Buddhist rituals, which implies that the corpses or human remains are present 31 . However the practices of the reformed mahānikāy, also widespread in Cambodia in the 1980s, while using the same prayers, have a different meaning and do not involve the physical presence of the dead : the offering of a piece of clothing to the monks is simply perceived as producing merit which is sent along to the dead. So in many cases, the fact that the corpse was not recovered does not bear the same importance as in Vietnam where those who have "died in the street" can not benefit from the cult of the ancestors until the corpse is given back to the family 32 .

Furthermore, some aspects of the treatment of the dead "without a corpse" are similar to those of the dead "with a corpse". 31 Bangskol is originally the worthless fabric used to make the monks' habits according to the first of the thirteen ascetic rules. In the non reformed tradition, the corpse or the ashes are covered with the bangskol. The monks pull on the clothes while they are praying, symbolically appropriating an old fabric found on a corpse (as did the ascetics in early times). The ritual of the old mahanikay sect symbolizes self-sacrifice and re-birth, according to François Bizot's analysis. François Bizot, Le don de soi-même. op. cit. 32 Heonik Kwon, op. cit., pp. 83-102.

Firstly, data from my research in Pursat suggests that cremation, although generally performed, is not essential. In the monasteries, several graves whose owners are said to be "Khmer" and not only "of Chinese origin" 33 can be seen near the stupas containing the ashes.

Even senior monks sometimes choose to be buried rather than cremated according to their "personal taste", as I was told in one such monastery where the abbot had ordered the building of an ornamented bier in a "cool place" on the riverside where his body was put after his death. Burials can also be temporary and furthermore, ashes are sometimes buried in the stupa. It is as if the Khmer ritual treatment of the dead needed to remain linked with the earth rather than fire. Indeed, the "abandonment [of the corpses] in the forest" (ka boh chaol knong prey smosan, ករេបះេចលកន ុ ងៃ្រពសម ន) is one of the four manners of treatment of corpses prescribed by Theravada Buddhism, the current abbot of Koh Keav monastery told me 34 . Secondly, many aspects of the treatment of the "normal" dead are collective just like the state rituals in front of the memorials described above, and also the main Festival of the Dead described below. For example, monasteries often have a collective stupa. If not, individuals make an offering to the monks (proken, ្របេគន) of their own family stupas so that other people can use them and bring their own family funeral urns.

The difference between the rituals for "good" and "bad" deaths is not great. In both cases, the main purpose of the death rituals is to "dedicate merits" (oteuh kosal, ឧទទ ិ សកុ សល)

to the dead in order to make their future existence as good as possible. This is the case for the bangskol performed when death occurs as well as for other ceremonies known as pachay 33 Jean Delvert in his classical monography, has written that the kind of funeral, cremation or burial, gives information on the Khmer or Chinese cultural badkground. See Jean Delvert (1994 [1rst publ. 1961]), Le paysan cambodgien, L'Harmattan, Paris, p. 26. 34 The three other manners are cremation, burial, and drowning in the Ganges (not carried out in Cambodia).

Offering of corpses to the birds was carried out until the beginning of the 20 th century. Abandonment of the corpse in the bush was described before the Pol Pot regime by François Bizot as a practice of the non reformed mahanikay sect. See Adhémard Leclère, La Crémation…, op. cit., pp. 72-73 and François Bizot, Le Don de Soimême, p. 15. bouen (បចច ័ យ៤ 35 ) or tokkhenanobotean, (ទកខ ិ នុ បបទន 36 ). In other smaller rituals, people who want to worship their dead whose bodies have not been found can make offerings to the monks while giving the dead person's name to the achar (lay specialist of the cult) so that he can send the merits to this person through his prayers.

When the annual festival of the dead was re-established in the early 1990s, it became easier to pay tribute to them. I myself witnessed a huge relief among the population in the days following the first festival, as if the atmosphere was suddenly lighter and quieter. This traditional festival is known in Khmer as the Gathering of the Riceballs festival (phchum ben, ភជ ុ ំ បិ ណ ្ឌ ) 37 . The festival was particularly relevant to paying tribute to the dead whose bodies were missing and had not received proper funerals because the phchum ben is essentially a collective ritual which aims at helping all the "souls" to reincarnate. This is the very meaning of the making of the riceballs (បិ ណ ្ឌ , ben, from Sanskrit pinda) by villagers over a two-week period in the monasteries during the lunar month of September-October (photrobot). The riceballs (ben) are less an offering of food than a back-up for reincarnation offered to the wandering souls. Ben therefore symbolize the human "shape" (រូ ប, rup, from sanscrit rūpa) 38 .

One can also assume that during the phchum ben, calling the name of the dead leads to the combination of the "name and shape" (នមរូ ប, neamrup) constituting the entirety of a human 35 Pachay means the money offered to the monks (pali, paccayo). See Father Tandart (1935), Dictionnaire cambodgien-français, Albert Portail publish., Phnom Penh. This big private ceremony is organized for the dead father and mother as a mark of gratitude. Four kinds of offerings (hence the name pachay 4) must be made to the monks and "the organizer should not regret at any moment the huge amount of money spent", following an achar (lay specialist of rituals). 36 Tokkhena means "alms". This is a less prestigious private ceremony which consists essentially of meals offered to the monks who can either bring the food to their monastery (េវរសងឃទន, ve sang tean) or eat where the ceremony is performed (េវរប្រតទន, ve bat tean). being.

One might think that the rituals performed and the efforts made to look ahead meant that the unknown dead of the mass graves, killing fields and memorials had been forgotten or at least kept at a distance from the living. This is true, but is not the end of the story, only its beginning. The Khmer system of mourning and memory is not based on a linear principle which would suppose that suffering and loss would be gradually lessened by the work of time and rituals of death. It is based on a circular principle that could be called "switch on/switch off". During a second phase, the dead burst forth again from time to time into the world of the living, especially via dreams. Let us continue listening to M. Sophon's experience.

"One night, five or six years ago [twenty-four or twenty-five years after the genocide],

I dreamt of a man named Sok. He told me that he did not know where to go. He was a dead person from the memorial. So the next morning, with the help of a neighbour, I carried all the human remains from the memorial to another place near the railway behind my house. This was a good place to put the remains because the dead could then go whenever they wanted, towards the east or the west. They could go back to their native land (srok). So we burnt all the remains there. I lit three incense sticks and prayed for the dead, asking them to go back home. And since then, I make offerings of water, rice and food to them every year during the Gathering of the Riceballs Festival (phchum ben)."

The dead are still connected to the living via the dreams in which they can speak and ask the living to fulfil their needs. In M. Sophon's case, they asked for a funeral ritual to be performed. In other cases, they can "behave" like land spirits. When I interviewed people living around the mass graves about their relationship with these places, it became progressively clear to me that there were many similarities between these dead and the neak ta land guardian spirits. The similarities refer firstly to the relationship with the natural environment, secondly to the relationship with death, and thirdly to interactions with the living. I will discuss these three points now.

The dead of the mass graves and the land guardian spirits

The neak ta land guardian spirits

Neak ta means literally "person-old male" or "person-grand-father" while in Pursat, they are usually called lok ta ("Mister grandfather" used as a term of address as well as a noun 39 ). They are often perceived as the founding couple of the village, who cleared the forest and built the first houses 40 . They are therefore perceived as ancestors and are sometimes called neak ta chas srok (អន ក ចស់ ្រសុ ក, "neak ta old people of the village" 41 ). They are key elements of the Khmer popular religious system as spirits protecting and controlling the land and its inhabitants 42 and they play an important role in structuring village social life and strengthening the peasant community 43 . In post-genocide society, where hundreds of thousands of people fled from Cambodia or were moved to other provinces or towns, worshipping neak ta can also maintain a link with the native village or territory (srok). Each neak ta is believed to be the protector and the controller of a specific piece of land which can be as small as a part of a village or a monastery or as large as a province. This is the case of Grandfather Khleang Mueng 44 whose shrine is in the village where I worked. He is a powerful and well known neak ta protecting and controlling Western Cambodia and he is nowadays worshipped as far away as Long Beach, California 45 . The land guardian spirits communicate 39 Lok ta is a common term of address for old men including monks. 40 Referring to my own work in Pursat, I found that the female counterpart of the neak ta is sometimes implicit and somehow merged into the neak ta entity. 41 Choulean Ang, Les êtres surnaturels…, op. cit., p. 205-206. 42 Alain Forest adopts a constructivist analysis of the neak ta by suggesting that common personal spirits can be upgraded to the status of neak ta only if the whole peasant's community acknowledge them as such. See Alain Forest (1992), Le culte des génies protecteurs au Cambodge, L'Harmattan, Paris, pp. 37-40. 43 David Chandler suggests that the cult of the neak ta has also been instrumental in providing a sense of national unity. A royal-sponsored cult may have been established for the most important spirits, each controlling a part of the kingdom, as early as in the 9 th century and probably before. with the living through mediums called rup ("physical shape") or smeung rup (សម ឹ ងរូ ប)

although not all of them have mediums. I found in Pursat that these spirits (or at least some of them) also communicate through the dreams of the living.

Merging into the natural environment

Neak ta are located in specific places, mainly in specific trees like Sterculia foetida (េដើ មសំ េ ង, daeum samrong), Ficus religiosa (េដើ មេពធិ៍ , daeum po), tamarind trees (េដើ មអមព ិ ល, daeum ompil) 46 or in small monticles like termite mounds or hillocks. A small house is made for them resembling a human house. The object representing the neak ta (also called រូ ប, rup, "physical shape", like the human medium is) is very simple and unsophisticated and sometimes there is even no representation at all. In this case, the neak ta's house contains only offerings. When the physical shape exists, it is a piece of an old statue, or a raw stone, or a termite mound 47 . This clearly shows that the spirit is merged into the natural environment rather than simply staying in it 48 , just like the bodies of the victims of the Pol Pot regime. Indeed, the great majority of the corpses remain unidentified and have lost their individuality, at least in the local dwellers' perceptions 49 . They were heaped together in ponds, wells and earth in the forests and bush, and became part of the natural environment. They are often associated, just like the neak ta, with hillocks, big trees like daeum samrong (េដើ មសំ េ ង, Sterculia foetida), tamarind trees or termite mounds 50 . In the killing field of Don Am village (Tropeang Chong commune) which now looks like peaceful grassland, the corpses were gathered together by the villagers and put near a big white mango tree 51 . Termite mounds began to grow there some years later.

The dead of the mass graves behave as masters of the place, in the same way as the neak ta. They are "touchy" and "ill-tempered" and cannot stand a disrespectful attitude from the living walking through their places : using inappropriate words, behaving casually and taking natural resources without permission can bring punishment as bad as death to careless human beings. For instance, the powerful land spirit guardian Khleang Mueng is widely believed to have killed several Khmer Rouge soldiers who were cutting samrong trees near his shrine. In doing so, he showed his power. The power of the masters of the land can also be made visible through other appearances of animals like crocodiles, snakes or tigers, lights during the night, or supernatural events such as branches of trees moving by themselves from the roof of the shrine. Although I have never been informed until now that the dead of the mass graves could be as aggressive as Khleang Mueng, some of them are powerful enough to punish people who use their place without permission or behave badly. For example, in Don Am village, a female neighbour in her thirties (born just after the Pol Pot regime) experienced the anger of a dead person lying in a well where lots of corpses were thrown during the Democratic Kampuchea.

"Nobody dares to do anything in this place, like using or cutting down the trees. When I was a young girl, I once came here in order to pick some tamarind fruit. Suddenly, my foot slipped on the edge of the well and then a stone fell into it. The night following this event, I dreamt that a man wearing black shorts [she believes that this man was a Khmer Rouge soldier who was purged and thrown into the well 52 ] was angry with me and criticized me for 50 Until now I have not observed association with stones like in the case of the neak ta. 51 Mango trees are not usually the shelters of the neak ta but I assume that there were no other trees around, so the villagers decided to choose this unusual mango tree (white and bigger than ordinary ones) as a "meeting point" for the corpses. 52 Many Khmer Rouge cadres and soldiers were themselves killed in extensive purges targeting the "enemy".

throwing a stone into the well. The stone, he said, crushed (សងក ត់ , sangkot) the corpses in the hole. The next morning, I came back, offered incense sticks and begged forgiveness for my misbehaviour. I have never dreamt of this man again".

Energy is believed to emanate from the places where powerful neak ta dwell. Such places are said to be "powerful" (ខ ្ល ំ ង, khlang) and to be full of "energy" (មនបរមី , mean boromey). The same energy radiates from some mass graves and killing fields. Boromey is derived from the pali word "pāramī", which mean the ten Buddhist perfections leading to Nibbāna. François Bizot 53 has convincingly drawn a genealogy from the initial Buddhist meaning to the Khmer popular meaning of "'strength', 'power', 'sacred energy' emanating from a cult artefact". Following the South East Asian Buddhist tradition, he states, the Buddha left behind Him His image and the ten pāramī and made them the protectors of His Learning for five thousand years. The meaning of boromey has thus evolved into the power emanating from the statues themselves (enhanced by sacred relics left inside them), identified with the power of the guardians of those statues, often assimilated with spirits like neak ta.

My field work in Pursat showed me that boromey is perceived as a circulating energy present in some trees, stones, events, artefacts, people (especially of royal background), and spirits linked to special places. In particular, the trees housing the neak ta reinforce the power of the place and thus the neak ta's influence (ឥទធ ិ ពល, eitiphol or អំ ច, omnach) on the living.

Cutting down trees near the spirits' shrines is dangerous not only because this act would offend the master of the place, but also because it lessens its spiritual power. For instance, Grandfather Khleang Mueng is perceived by many villagers as less powerful than before the Pol Pot regime because many big trees such as samrong trees have been cut down around his shrine. Similarly, the spiritual energy boromey emanates from some mass graves and is "composed" of trees, events (slaughters), the spirits of the dead, and possibly stones, as well

The Khmer Rouge cadres and soldiers wore black pyjamas. 53 François Bizot (1994), 'La consécration des statues et le culte des morts', in François Bizot (ed.), Recherches Nouvelles sur le Cambodge, Publications de l'Ecole Française d'Extrême-Orient, Paris, p.116.

as offerings. The boromey emanating from them depends on the characteristics of the natural environment and possibly on the events linked to the death itself 54 .

Good and bad deaths

In his illuminating essay on neak ta, the French researcher Alain Forest sees the neak ta as "un mort présent chez les vivants 55 " (a dead person present in the world of the living 56 ).

He puts forward the hypothesis that the Khmer pre-Buddhist perceptions of death -as far as it is possible to know them through myths and ethnographic data -evoke the dead person's trips back and forth from the island of the dead to the realm of the living. After a period of time spent on the island of the dead, resembling the Meru mount, the dead are reborn in their native locality (srok). Alain Forest argues that, the neak ta is a spirit which, for some reason, has not been transformed into the spirit of a dead person sent to the island of the dead, and therefore cannot be reborn. In this way, it is similar (but not identical) to those who have died a bad death, those who have committed suicide, been murdered, drowned, struck by lightning, or have died in childbirth. Those who have died a bad death are called "uncooked ghosts" (េខ ម ចេឆ, khmauch chhau), firstly because they have not been cremated, and secondly because they do not belong to the village anymore ("cooked" is opposed to "uncooked" as the village/civilization is opposed to the forest/savagery, as Claude Levi-Strauss has shown in his classic study). They are believed to be dangerous for the living. In the countryside, they are left in the forest or the cemetery 57 . Although not all neak ta have died a bad death 58 , this is the 54 Not all the killing fields and the mass graves are perceived as "powerful". For example, in Andong Somboue village, the killing field is known as "the Svay Rieng rice field" because tens or hundreds (depending on the interviews) of people deported from the province of Svay Rieng were slaughtered there in 1978, including children and newborn babies, sometimes still alive near their mothers' bodies after the perpetrators left. Two or three children escaped and were adopted by the villagers. Apart from the name given to the place, there is apparently no remaining trace of the dreadful event. Nobody has witnessed any phenomenon suggesting a neak ta-like presence. But there were lights and ghosts in the night until some years ago. An old man told me that one night in 1992 or 1993, a villager saw all the ghosts walking in single file back to their native locality (srok). 55 Alain Forest, Le culte des génies, op. cit., p. 113.

56 A further piece of information is that the etymology of the modern Khmer word "grave" (ផន ូ រ, phnor) is the old khmer word "monticle" (vnur) where the neak ta live. Choulean Ang, Les êtres surnaturels, op. cit., p. 202. 57 Choulean Ang, Les êtres surnaturels, op. cit., pp. 102-103. 58 One of the reasons of it is that not all the neak ta have been human beings before becoming land spirits.

as an international tourist site supervised by the Ministry of Tourism 61 . The potential worship of one of the bloodiest dictators in world history appears strange and shocking at first glance, but it can be explained if we refer to the Cambodian popular religious world. In his lifetime, Pol Pot was a powerful man who could order the murder of whoever he wanted. This power remains after his death and it also associated with the place where he lived at the end of his life, and died. It is unclear if Pol Pot died of a heart attack (as the King-father writes in an article quoted above), committed suicide, or if he was murdered. In other words it is unclear if he died a "good" or a "bad" death. In any case, after his death, Pol Pot remains powerful, although this power can be used in a positive or a negative way, just like that of the neak ta.

He is believed to be able to help the living who come and speak to him but I assume that, on the contrary, he can harm those who are not respectful toward the place where his ashes have rested since his cremation. My hypothesis is that the more powerful the individual during his life, the more violent and associated with violence his life and death, the more powerful he will become as a neak ta (if he does become one). This is consistent with other findings such as the performance of a royally sponsored human sacrifice to an important neak ta, Me Sar ("the White Mother"), at Ba Phnom (province of Prey Veng) as late as in 1877 62 . Another example of the power emanating from the offering of a person who has been violently killed is the "grilled child talisman" (កូ ន្រកក, kon krak). This very powerful talisman is made by a man whose wife is three or four months pregnant. The husband must disembowel his wife and take the foetus from her womb. He then grills the foetus. The talisman cannot work if the child has not been given to the husband by his wife before the murder. Usually the man deceives his wife by cuddling her while asking her if she agrees that the child is his. When she answers that the child is of course her husband's child, the murderer is ready to take the foetus out of the mother 63 .

Intervening in the lives of the living

Neak ta establish relationships with the living, through their human medium -either in an unplanned way or during annual festivals paying tribute to them -or through dreams. They ask the living to fulfil their needs for food, cigarettes, shelter, etc. They can also give information on the aetiology of diseases, or predict the future. As for the "Pol Pot dead", I

have not been aware of any case of possession of a human being in Pursat until now 64 . Rather, I have listened to several stories of dreams in which the dead person asks the sleeper to fulfil his/her needs as in the case described above of M. Sophon and the dead Sok who wanted to be given a funeral ritual. In the following quite comical example told by a fifty year old woman, a dead person in a mass grave just wants… to watch a film on television. Stories about lottery numbers given in dreams are commonplace in Cambodia 66 as well as in other Southeast Asian societies. This shows how neak ta (and the Pol Pot dead) are able to intervene in the daily lives of the Cambodian people, while karmic destiny is a far more abstract concept. Indeed, lottery games, like all forms of gambling, are perceived as being related to karma. Being lucky shows how good the individual's karma is and this widespread perception is instrumental in the success of gambling games in Cambodia.

Finally, neak ta and the dead of the mass graves are different from one point of view :

neak ta are ambivalent invisible entities, who are able to punish the living but they are also keen to protect them. Many stories are told about people who were given useful information by neak ta during the Pol Pot regime so that they could survive. Until now, I have not heard that the mass graves/the dead protect the living. Instead, they behave as quick-tempered masters of the land.

Conclusion

In this article, I have analyzed the misunderstandings and discrepancies regarding the construction of justice and memories which occurred in the wake of the Khmer Rouge genocide. I have described in particular the sophisticated although unknown social device set up by the Cambodian peasants in order to express social suffering but also to give local meaning to the genocide. In the Khmer cultural system, the dead of the mass graves are not perceived as victims (as they are in the Tribunal) nor as proof of the Khmer Rouge savagery (as they are in the Cambodian People's Party's perceptions), neither are they ordinary dead.

My hypothesis is that at least some of them are spirits in the process of becoming land guardian spirits. Massive bereavement has been incorporated into the popular religious framework, particularly into the cult of the land guardian spirits with whom the dead of the mass graves share many characteristics. This allows a specific relationship between the dead and the living and a specific memory of the genocide consisting of alternately forgetting and remembering. I have suggested this "switch on/switch off" device of memory to describe the 66 Choulean Ang, Les êtres surnaturels, op. cit., p. 216.

way in which the dead of the memorials were "forgotten" for a while when the living were busy rebuilding their lives after the mass destruction, by planting trees and setting up markets on the old killing fields, or when the dead person talking to a woman in her dreams stopped doing so after a while, becoming in return less worshipped until his shrine fell into ruins.

These dead people, nonetheless, can burst into the daily lives of the living at any time. For years and years, from one generation to another, they will talk about the genocide and give it meaning in their own way -in a very different way from the kind of memory legitimized in Western societies. Via such "powerful places" as mass graves there is a possibility of the building and re-building of the meaning and memory of the genocide, in relation to the present.

  This land has long belonged to my family. I was ten years old when I was deported to Kravanh district by Pol Pot. My sister died at that time [M. Sophon also personally witnessed several murders]. I came back here soon after the Pol Pot regime ended. In 1979, there were a lot of mass graves with four or five corpses in each pit. The head of the sub-district (mekhum) asked us to put the skulls and other remains together and to erect a small building there, in order to keep them. He organized a bangskol celebration twice. At the beginning I was afraid here. Everybody was afraid. One day, the mekhum caught a thief and punished him by locking him inside the memorial with the skulls. The thief screamed the whole night and I can tell you he has never stolen again! One night, I saw a light like a ap ( ប 26 ) in the mango trees and the tamarind trees. Nobody dared to go out at night. But later on, the memorial gradually fell into ruins because nobody took care of it any more. And after a while, the ghosts (េខ ម ច, khmaoch) became harmless, unable to bother the living (literally "tasteless", ប, sap). So we were no longer afraid. Later on, I planted banana trees in the field of the memorial. But when I work in my field, I keep on digging up remains." M. Sophon's narrative is representative of other stories I have heard from villagers living near mass graves. Many people saw ap-like lights in the night near the memorials and former killing fields and a young man even told me that his younger sister lost all her hair after having seen such a light 27 . The widespread fear of ghosts/corpses 28 was due to the fact that most of the dead of the Pol Pot regime died a "bad death" without a proper funeral. Like in other South East Asian societies, people who commit suicide, are murdered, have fatal accidents or die during childbirth are perceived as "bad dead" (khmaoch tai hong, េខ ម ច យេ ង meaning literally « violent death ») in opposition to "normal death" caused by old age and ordinary diseases (i.e. associated with natural aetiology). Shorter funeral rituals are usually performed and the risk exists that these dead would not follow the usual way of the saṃsāra but would transform into malevolent entities of various forms staying near the living. The victims of the Pol Pot regime potentially belong to this second category.

"

  In 1992 [more than ten years after the genocide], I dreamt that a voice coming from the well [in Don Am village, where the bodies were piled up] told me: 'Please come and give a video projection! The winning lottery number is 21'. The next day, I ran to buy a lottery ticket and won three million riels [around 750 dollars]. Then my husband and I built a small house (ខទ ម, khtom 65 ) to say thank you and we invited all the nearby villagers to watch a video.The video projector was installed near the mass grave as requested in the dream. Then, during the next Gathering of the Riceballs Festival (phchum ben), we made offerings to the dead of this mass grave. Later on, I dreamt once again of a voice coming from the well and revealing to me the winning lottery number. But later on, I never won again. [So she progressively lost interest in the mass grave and neglected to go and worship the place/the dead. Then the khtom fell into ruins]. But from time to time when I have a dream or fall sick, I always go to the well and offer incense sticks."63 Choulean Ang, Les êtres surnaturels, I have witnessed in other circumstances and places the informal possession of a neighbour by the spirit of a person who has just died of bad death.65 Khtom is a temporary shelter built by peasants in the fields. It is also one of the names used for the neak ta's shrine.

,

  Les Etres Surnaturels dans la Religion Populaire Khmère, CEDORECK, Paris. 8 The 2008 survey of the Documentation Center of Cambodia indicates 19.521 mass graves throughout the 180.000 square kilometres of Cambodia.

  Tribunal Populaire Révolutionnaire Siégeant à Phnom Penh pour le Jugement du Crime de Génocide Commis par la Clique Pol Pot-Ieng Sary. Documents (1990), Maison d'Edition en Langues Etrangères, Phnom Penh. 21 It still remains unclear to me why the verb sang song is used in this context as a noun without the usual prefix kar (ករ).

They were made of wood or bricks covered by a roof of palm leaves or tiles. More than eighty memorials were built in Cambodia in the 1980s according to the Documentation Centre of Cambodia. Officials of the Party who were appointed members of the newly created Committee of organization of national celebrations (គណៈកមម ធិ កេរៀបបុ ណយជតិ , kanakamathikar reap bon cheat) came to the communes 20

  Rachel Hughes quotes a 1983 memo from the Ministry of Information and Culture urging provincial authorities to build at least one memorial in each province prior to the fifth anniversary of National LiberationDay, 1984. See Rachel Hughes (2006), Fielding genocide: post-1979 Cambodia and the geopolitics of memory, Phd. diss., University of Melbourne, p. 117. I agree with this author when she reckons that the memorials have played different roles -including that of organizing public mourning -and cannot be seen only in the negative manner of a pure strategic instrument of empowerment for the Cambodian People's Party. Moreover, Cambodian society is in the process of constructing a modern national identity and further analysis will be needed on the genocide as one of the founding events of this construction. abandoned in most communes, including the two I visited in Trapeang Chong and Snam Preah communes24 . Nobody was interested any more in repairing and looking after these symbols of the genocide. This was concomitant with the collapse of the Cambodian Communist State and state-run facilities (such as ministries, hospitals, and schools) following the rise of political liberalization and the free-market economy. Moreover, these memorials had been set up at a particular time (cold war, Khmer Rouge guerrilla, isolation of Cambodia, flow of refugees) with ideological and strategic objectives which no longer existed after 1991, when the Peace Agreement was signed between the four Cambodian parties, followed by the establishment of the United Nations Transitional Authority in Cambodia 25 . As a former district deputy chief of Bakan told me when I asked him why the memorials were not looked after in the 1990s: "Government policies were changing and we did not know what the future would be like, so we sold the state land [including the collective land where the memorials were built]. Moreover, when Prince Sihanouk came back [in 1991], we were told that our government was making an agreement [with the opposition parties including the Khmer

22

On the different meanings of bangskol in non reformed and reformed mohanikay Cambodian sects, see François

Bizot (1981)

, Le Don de Soi-même. Recherches sur le Bouddhisme Khmer III, Publications de l'Ecole Française d'Extrême-Orient, Paris.

23

Rouge]. There were two opposite opinions on the subject of the memorials. The first one stated that it was important to keep the bones (ឆ្អ ឹ ង, chh'eung) as a proof [of the genocide].

  Tribute to the Spirits [of the dead of the Pol Pot regime]). In Pursat and elsewhere, the rituals 24 Some memorials are still looked after for different reasons and by different organizations, all over the country. See Rachel Hughes (2005), 'Memory and sovereignty in post-1979 Cambodia: Choeung Ek and local genocide memorials' in Susan Cook (ed.), Genocide in Cambodia and Rwanda: New perspectives, Transaction Publishers, NewBrunswick, NJ., pp. 257-280; Jean-Louis Margolin (2007), 'L'Histoire brouillée. Musées et mémoriaux du génocide cambodgien', Gradhiva. Musée du quaiBranly, Paris, N° 5, Rachel Hughes rightly names this period a "suspended historicity" before the process of commemoration was resumed in the 2000s. See her PHd diss., op. cit.

  37 It was named the Festival of the Dead during the French protectorate and this name is still used among Westerners. 38 I am indebted to Choulean Ang who gave me a copy of his unpublished research presenting this analysis of Phchum ben. See also Commission des Moeurs et Coutumes duCambodge (n.d.), Cérémonies des douze mois, Institut Bouddhique, Phnom Penh, p. 47-58.

  David Chandler (1976), 'Maps for the Ancestors: Sacralised Topography and Echoes of Angkor in two Cambodian Texts', Journal of the Siam Society, Vol. 64, N° 2, pp. 170-187.44 Khleang Mueng is a name of Thai origin which means "central pillar of the district".45 Teri Shaffer Yamada (2004), 'The spirit cult of Khleang Moeung in Long Beach, California', in John Marston and Elizabeth Guthrie (eds.), History, Buddhism, and New Religious Movements in Cambodia, University of Hawai'I Press, Honolulu, pp. 213-225.

The Pol Pot regime had divided the population into two categories, the "old people" and the "new people" depending on when they joined the revolution. The "old people" who lived in areas under communist control prior to 17 April 1975 were generally better treated than the "new people" especially regarding punishments. Some interviewees in Pursat suffered seriously from hunger but were not mistreated. They sometimes even appreciated social justice and the improvement of agriculture through the construction of waterways (implicitly criticizing the current government which does not take care of the infrastructure). However, many other villagers saw their relatives dying from hunger, overwork, or execution.

An ap is a female witch who belongs both to the natural and supernatural world. She goes out at night, her head and bowel floating low in the air and emitting a phosphorescent blue light. She is linked with bad death and human waste. See Choulean Ang, Les êtressurnaturels, op. cit., pp. 263-284.

Choulean Ang (Les êtres surnaturels, op. cit., p. 202) also mentions daeum slaeng (Strichnos nux vomica) and daeum chrey (Ficus Spp.).

However in towns, new statues with human bodies and faces are progressively replacing the old altars. This indicates an evolution in the worship of the neak ta that I cannot discuss here.

PaulMus (1934), 'Cultes Indiens et Indigènes au Champa', Bulletin de l'Ecole Française d' Vol. 33, N° 1, p. 374.

Some well off families who have been able to locate the place where their parent died make offerings to the neighbouring monasteries. This is thus a middle-term ritual between the collective and anonymous treatment of the mass graves and the memorials, and individual funerals. During these ceremonies, the name of the dead person is called and the usual ritual of "dedicating merits" (oteuh kosal, ឧទទ ិ សកុ សល) is performed.

The text was published in French: 'Les âmes errantes des victimes des Khmers rouges polpotiens', Bulletin Mensuel de Documentation, 25 July 2006. Quoted by Olivier de Bernon, 'Du manifeste à l'obscénité commerciale. Le traitement du souvenir des victimes des Khmers Rouges à Phnom Penh et dans les environs', in Higô no shi no kioku. Tairyô no shisha o meguru hyôshô no poritikusu [Collective death. Memory building and politics] (in Japanese), ed. Anne Bouchy and Masaru Ikezawa (Tôkyô: Akiyama shoten publisher).

Kate G. Frieson (1993), 'Revolution and rural response in Cambodia: 1970-1975' in Ben Kiernan (ed.), Genocide and Democracy in Cambodia: the Khmer Rouge, the United Nations and the International Community, Yale University Southeast Asia Studies, Monograph series, New Haven, Conn., pp. 33-50; May Ebihara (1993), 'A Cambodian Village under the Khmer Rouge, 1975-1979', in Ben Kiernan (ed.) Genocide and Democracy in Cambodia., op. cit., pp. 51-63; May Ebihara (2002), 'Memories of the Pol Pot era in a Cambodian village' in Judy Ledgerwood (ed.), Cambodia Emerges from the Past: Eight Essays, Center for Southeast Asian Studies, Northern Illinois University, DeKalb, IL., pp.91-108; Ebihara May and Judy Ledgerwood (2002), 'Aftermaths of Genocide: Cambodian villagers' in Alexander Hinton (ed.), Annihilating Difference: The Anthropology of Genocide, University of California Press, Berkeley, pp. 272-291; Eve Monique Zucker (2006), 'Transcending time and terror: the re-emergence of bon dalien after Pol Pot and thirty years of civil war', Journal of Southeast

case of one of the most famous ones, Grandfather Khleang Mueng, who was a local major in King Ang Chan's army (sixteenth century). The Khmer army was fighting a stronger Siamese army in Pursat. Out of desperation, Khleang Mueng offered to commit suicide with his wife, his children and his troops in order to ask for the help of an army of ghosts. He did so and many Siamese soldiers died from diarrhoea and the army was defeated 59 . The fact that Khleang Mueng offered his life and died violently makes him particularly powerful as a neak ta. As an old keeper of the shrine puts it: "Grandfather Khleang Mueng is powerful because he chose to kill himself". In sum, the dead of the mass graves can easily be "elected" as neak ta due to their bad death in violent and terrifying circumstances.


Diane Deroualle

Liliane Borel

Brandon Tanguy

Laurence Bernard-Demanze

Arnaud Devèze

Marion Montava

Jean-Pierre Lavieille

Dr Christophe Lopez
email: christophe.lopez@univ-amu.fr

Unilateral vestibular deafferentation impairs embodied spatial cognition

Keywords: Perspective taking, Vestibular system, Unilateral vestibular loss, Mental imagery, 3D object mental 56 rotation

Introduction

58

A growing number of studies indicate that cognitive complaints are common in patients with vestibular 59 disorders (reviewed in [START_REF] Smith | The vestibular system and cognition[END_REF][START_REF] Bigelow | Vestibular involvement in cognition: Visuospatial ability, 493 attention, executive function, and memory[END_REF]). For example, a recent epidemiological study in US adults revealed that

Visual stimuli and tasks 125

3PP taking task. Participants were involved in a virtual ball-tossing game [START_REF] Deroualle | Changing perspective: The role of 531 vestibular signals[END_REF]. Visual stimuli showed 126 6 avatars around a circle (see Figure 1A and the legend, for details). Participants were instructed to 127 adopt the perspective of the avatar holding the ball (identified by a blue T-shirt) and from this position 128 to toss the ball to the avatar wearing a red T-shirt. They indicated as quickly and as accurately as possible 5 whether they had to toss the ball to the right or left, by pressing on a respond pad [START_REF] Deroualle | Changing perspective: The role of 531 vestibular signals[END_REF]. There was no 130

time limit to answer. The experiment was a 5 Angle of visuo-spatial perspective taking (5 positions of 131 the avatar holding the ball: ± 60°, ± 120° and 180°) × 4 positions of the avatar receiving the ball (± 60° 132 and ± 120° with respect to the avatar holding the ball) design, with four repetitions of each of the 20 133 stimuli. Participants completed 80 trials divided into 4 blocks of 20 trials presented in a random order. 134 135 1PP task. Five avatars were shown in the visual scene (Figure 1B) and the hands holding the ball in the 136 front of the scene indicated that participants had to toss the virtual ball from their 1PP [START_REF] Deroualle | Changing perspective: The role of 531 vestibular signals[END_REF]. Participants 137 indicated as quickly and accurately as possible whether they had to toss the ball to their right or left (to 138 the avatar located at ± 60°, ± 120°) without time limit. Each of the four visual stimuli was repeated four 139 times in one block of 16 trials presented in a random order.

141

Visual detection task. A visual detection task [START_REF] Deroualle | Changing perspective: The role of 531 vestibular signals[END_REF] was used to control for potential attentional and visual 142 differences between groups of participants (Figure 1C). In 10 trials, one avatar held a ball, while in 10 143 other trials, no ball was shown. Participants were instructed to detect as quickly and as accurately as 144 possible that there was a ball in the visual scene, without time limit. Participants completed one block 145 of 20 trials presented in a random order. 146 147 3D objects mental rotation task. Twenty out of 23 patients were involved in a 3D objects mental rotation 148 task [START_REF] Péruch | Vestibular information is necessary for 511 maintaining metric properties of representational space: Evidence from mental imagery[END_REF]. Pairs of identical or different 3D objects were presented side by side on a computer screen 149 (Figure 1D). When identical, the second object was rotated with respect to the first object by 20°, 40° 150 or 80°. We instructed participants to imagine a rotation of one of the objects to align it with the other 151 and to indicate as quickly and as accurately as possible whether the objects were identical or different.

152

There was no time limit to answer. There were two blocks of 36 pairs of objects, of which 24 were 153 identical and 12 were different. Pairs of objects were presented randomly within each block, and the 154 presentation of the blocks was counterbalanced.

156

Experimental procedures 157

Participants were tested while comfortably sitting on a chair with their head maintained by a forehead 158 and chin rest. SuperLab 4.5 (Cedrus Corporation, USA) was used to present visual stimuli on a computer 159 screen (64.4 × 49.4 cm) placed 50 cm in front of the participants. Thirteen patients and controls first 160 completed the 1PP task and then the 3PP taking task, while the others started with the 3PP taking task.

161

All participants finished with the visual detection task and the 3D objects mental rotation task.

162

Participants took short breaks after each block and task. Before the experiment, they trained to each task 163 with a random selection of 10 trials. After the experiment, participants filled out a questionnaire about 164 the strategies they used. They indicated whether it happened during the experiment they imagined 6 rotating the entire visual scene with the avatars to solve the 3PP taking task. If it was the case, they were 166 asked to rate how often they did it, using a 7-point Likert scale ranging from 'rarely' to 'all the time'.

168 169

Data analysis 170

For each participant and task, we calculated the mean response times (RTs) and percentage of errors.

which RTs exceeded 2 standard deviations of the participant's grand average. As the Shapiro-Wilk test 173 revealed not normally distributed RTs for most of the dependent variables, we used a log transformation 174 and applied repeated-measures ANCOVA when this procedure led to normal distribution. Variables that 175 remained non-normally distributed and the percentage of errors were analysed using non-parametric and performance in the cognitive tasks. To minimize the risk of false positives, we used Bonferroni-181 corrected α level of P < 0.05/13 for statistical significance (P < 0.0039).

Results

185

3PP taking task 186

Response times. RTs were first analysed using a repeated-measures ANCOVA with Angle of 3PP taking 187 as within-subject factor, Group and Gender as between-subject factors, and Age as covariate. Age was 188 significantly related to RTs (F1,39 = 12.19, P < 0.005), whereas Gender was not (F1,39=0.08, P = 0.77).

189

Importantly, we found a significant effect of the Group after controlling for the effect of Age (F1,39 = 190 4.40, P < 0.05). Figure 2A shows significantly larger RTs for 3PP taking in patients than in controls.

191

As expected, the analysis shows a significant effect of the Angle of 3PP taking (F3,107 = 2.78, P < 0.05),

192

with longer RTs for larger angles of perspective taking (Greenhouse-Geisser correction, ε = 0.69). There 193 was no significant interaction between Angle and Group, or with the covariate. RTs were not 194 significantly related to the grade of the neuroma (Kruskal-Wallis test, P > 0.05) (Figure 2B).

195

In a second analysis, we explored how the side of neurectomy influenced 3PP taking. We found 196 that patients with left neurectomy showed significantly larger RTs than their age and gender-matched 197 controls (F1,17 = 6.81, P < 0.05) (Figure 2A). There was no other significant main effect or interaction, 198 but Age was significantly related to RTs (F1,17 = 8.04, P < 0.05). By contrast, patients with right 199 neurectomy did not differ from their controls (F1,17 = 0.04, P = 0.84) (Figure 2A). The effect of Angle 200 of 3PP taking was not significant after Greenhouse-Geisser correction (F2,38 = 2.53, P = 0.09), but the 7 effect of Age was significant (F1,17 = 7.74, P < 0.05). Direct comparison of patients' performance with 202 left and right neurectomy did not reveal significant differences in RTs (F1,17 = 2.42, P = 0.14). Thus, the 203 effect of Group observed in the whole-population analysis seems to arise from altered 3PP taking mainly 204 in patients with left neurectomy. We note that this result cannot be accounted for by different vestibular 205 functions in patients with left and right neurectomy (see Table 1).

207

Errors. Friedman's tests revealed an effect of the Angle of 3PP taking on the percentage of errors in 208 patients (χ 2 (4) = 25.7, P < 0.001) and controls (χ 2 (4) = 37.8, P < 0.001) (Figure 2C). However, Mann-

209

Whitney tests did not reveal a significant effect of the Group (-60°: P = 0.13; -120°: P = 0.

3D objects mental rotation 233

Response times. A repeated-measures ANCOVA revealed a significant main effect of Angular disparity 234 (Greenhouse-Geisser correction, ε = 0.67: F1.3,47 = 18.95, P < 0.0001), with longer RTs for larger angles 235 of mental rotation. In contrast with the 3PP taking task, there was no significant effect of the Group 236 (F1,35 = 0.15, P = 0.71) (Figure 3A). We found no significant effect of Age (F1,35 = 3.07, P = 0.09) and 237 Gender (F1,35 = 0.47, P = 0.50), but there was a significant interaction of Angular disparity × Age (F1.3,47 238 = 3.01, P < 0.05). Similar analyses conducted separately for patients with left and right neurectomy 239 revealed no effect of the Group (left: F1,15 = 0.09, P = 0.78; right: F1,15 = 0.03, P = 0.87) (Figure 3A).

241

Errors. Friedman's tests revealed a significant effect of Angular disparity in patients (χ 2 (2) = 27.3, P < 242 0.0001) and in controls (χ 2 (2) = 22.7, P < 0.0001), with more errors for larger angles of mental rotation

243

(Figure 3B). Mann-Whitney tests showed a statistical trend for higher percentage of errors in patients

247

Clinical data and their correlation with visuo-spatial cognition 248

Table 1 shows that overall the two groups of patients did not differ with respect to their clinical 249 status, with the exception of worse postural performance in patients with right than left vestibular 250 loss, and a larger proportion of cophosis at D+7 in the patients with left vestibular neurectomy. There 251 was an important variability in the presurgical vestibular functions, owing to the different locations 252 and grades of the neuroma [START_REF] Koos | Neurotopographic considerations in the 549 microsurgical treatment of small acoustic neurinomas[END_REF]. Thus, we calculated partial correlations between clinical parameters 253 and cognitive performance, while controlling for the effects of age (as RTs for 3PP taking were 254 related to age). There was no significant correlation between clinical parameters and cognitive

Different effect of vestibular disorders on egocentric vs object-based mental imagery 264

The present data show that patients tested one week after unilateral vestibular neurectomy had impair 265 3PP taking abilities, as revealed by longer RTs in patients than in controls. Interestingly, no deficit was 266 found when patients were required to toss the virtual ball from their 1PP, that is, when no own-body 267 mental transformation was necessary. This indicates that deficits in 3PP taking were not merely related 268 to attentional or oculomotor deficits to explore the visual scene and to discriminate left/ right orientations 269 (see below). Rather, our results speak in favour of a more specific vestibular contribution to perspective 270 taking and highlight the specific role of vestibular information in embodied spatial cognition [START_REF] Deroualle | Toward a vestibular contribution to social cognition[END_REF].

271

Another recent study, in which patients with objective balance deficits were required to imitate lateral 272 body tilts of an avatar, showed longer movement latencies and more errors in the patients [START_REF] Allum | Mental body transformation deficits 505 in patients with chronic balance disorders[END_REF]. Our results 9 are also in line with a previous study in healthy participants using the same 3PP taking task, showing 274 that natural vestibular stimulation (on a rotating chair) helped to adopt the perspective of a distant avatar 275 when the directions of the physical rotation and simulated viewpoint were congruent [START_REF] Deroualle | Changing perspective: The role of 531 vestibular signals[END_REF].

276

Although our participants were trained to use explicitly own-body mental imagery during the 277 3PP taking task, we cannot exclude that some of them used other strategies, such as simulating a 'bird

283

In contrast with the 3PP taking task, the unilateral vestibular neurectomy had no effect on 3D 284 object mental imagery. There are only few studies about the consequences of vestibular disorders on 285 object-based mental imagery and they showed divergent results. Impaired object-based mental imagery 286 seems to depend on the extent of the vestibular loss, as patients with bilateral loss were the most impaired 287 [START_REF] Grabherr | Mental transformation abilities in patients 508 with unilateral and bilateral vestibular loss[END_REF][START_REF] Péruch | Vestibular information is necessary for 511 maintaining metric properties of representational space: Evidence from mental imagery[END_REF], and on the compensation stage, as deficits were found only in the early stage after vestibular 288 neurectomy [START_REF] Péruch | Vestibular information is necessary for 511 maintaining metric properties of representational space: Evidence from mental imagery[END_REF][START_REF] Candidi | Impaired mental rotation in benign 514 paroxysmal positional vertigo and acute vestibular neuritis[END_REF].

289

Altogether, our data suggest that acute unilateral vestibular deficits affect differently visuo-290 spatial tasks involving mostly egocentric mental imagery (3PP taking) and object-based mental imagery.

291

We propose that shared neural networks are involved in encoding own-body rotations (vestibular cortical 292 network) and in simulating own-body and viewpoint rotations (3PP taking). This proposition is first 293 supported by our previous results in healthy participants showing that whole-body rotations on a rotating 294 chair influenced 3PP taking in a direction-specific way, but not object-based mental imagery [START_REF] Deroualle | Changing perspective: The role of 531 vestibular signals[END_REF].

295

Second, a recent fMRI study [START_REF] Macauda | Shared neural mechanisms between imagined 546 and perceived egocentric motion -A combined GVS and fMRI study[END_REF] showed that clockwise/counterclockwise mental rotation of the 296 observer's viewpoint (as used in our 3PP taking task) and galvanic vestibular stimulation both activated 297 the bilateral posterior insular cortex and the right parietal operculum (OP2), two core areas of the 298 vestibular cortical network.

300

Different effect of right vs left vestibular disorders on perspective taking 301

A main result of the present study is that 3PP taking abilities depended on the side of vestibular 302 deafferentation. Only patients with left neurectomy showed larger RTs in the 3PP taking task, when 303 compared to their controls. This was not the case when visuo-spatial judgements were performed from 304 their 1PP. However, patients with left neurectomy were also slower for the visual detection task. This 305 indicates that left vestibular loss is more likely to disturb the mechanisms of egocentric own-body mental 306 imagery and alertness than the mechanisms of visuo-spatial tasks that do not require egocentric mental 307 imagery (i.e., 1PP task and 3D object mental rotation). It is difficult to compare our data with previous 308 studies as only few of them have investigated spatial cognition with respect to the side of the vestibular 309 loss. In line with our findings, Saj et al. [START_REF] Saj | Where is straight ahead to a patient with 522 16 unilateral vestibular loss?[END_REF] found that only left vestibular neurectomy significantly 10 deviated the perceived straight ahead. Left cathodal galvanic vestibular stimulation also impaired mental body schema [START_REF] Lopez | Distorted own-body representations in patients 556 17 with dizziness and during caloric vestibular stimulation[END_REF]. However, opposite data have been reported, with slower recovery of the subjective 313 visual vertical in right vestibular neuritis [START_REF] Toupet | Influence of body laterality on recovery 559 from subjective visual vertical tilt after vestibular neuritis[END_REF], and a trend for poorer spatial navigation in right vestibular 314 deficits [START_REF] Hüfner | Spatial memory and hippocampal volume 525 in humans with unilateral vestibular deafferentation[END_REF]. Another study reported no effect of the side of the vestibular loss on cognitive deficits [START_REF] Popp | Cognitive deficits in patients with a chronic 499 vestibular failure[END_REF].

315

The discrepancy between these data may be related to the diversity of the spatial functions tested, 316 involving different brain areas.

317

Why would left vestibular neurectomy impair 3PP taking? Neuroimaging studies have 318 emphasized a right hemispheric dominance of vestibular processing in right-handed participants [START_REF] Dieterich | Dominance for vestibular cortical function in 517 the non-dominant hemisphere[END_REF] -319 as were our participants. Accordingly, a stronger impact of right vestibular neurectomy on 3PP taking 320 can be expected. Our results do not support this hypothesis. However, they are in line with neuroimaging 321 data showing different compensation patterns in acute right and left vestibular neuritis, with a shift of 322 the dominant ascending input from the ipsilateral to the contralateral pathways [START_REF] Becker-Bense | The differential effects of acute 537 right-vs. left-sided vestibular failure on brain metabolism[END_REF]. Alternatively, based 323 on results from a diffusion tensor imaging study of the vestibulo-thalamo-cortical pathways [START_REF] Dieterich | Right-sided dominance of the bilateral vestibular 519 system in the upper brainstem and thalamus[END_REF], we 324 predict that right vestibular neurectomy would predominantly disrupt multisensory processing in the 325 right parieto-insular cortex, whereas left neurectomy is more likely to disrupt multisensory processing 326 bilaterally in this area. We propose that left vestibular neurectomy evoked deficits in 3PP taking by 327 disrupting bilateral areas underpinning 3PP taking. Of note, an fMRI study [START_REF] David | Neural representations of self versus 534 other: visual-spatial perspective taking and agency in a virtual ball-tossing game[END_REF] described the neural 328 correlates of 3PP taking in a virtual ball-tossing game similar to that used in the present study. 3PP 329 taking, when compared to 1PP, activated bilaterally the anterior insula and medial frontal cortices, as 330 well as the left inferior parietal lobe. As 3PP taking involves a bilateral network of insular and parieto-331 frontal areas, we anticipate that it is very likely more affected by predominantly bilateral vestibulo-332 thalamo-cortical projections from the left vestibular receptors [START_REF] Dieterich | Right-sided dominance of the bilateral vestibular 519 system in the upper brainstem and thalamus[END_REF].

334

Role of visuo-spatial attention and alertness 335

Patients had longer RTs than controls in the visual detection task, and RTs for the 3PP taking task and 336 the visual detection task were larger after left than right vestibular neurectomy. As previous studies have 337 related vestibular loss to poorer visuo-spatial ability and attention [START_REF] Bigelow | Association between visuospatial 562 ability and vestibular function in the Baltimore longitudinal study of aging[END_REF], we cannot exclude that larger 338 attentional deficits in patients with left neurectomy contributed to larger RTs for 3PP taking. However, 339 as RTs were not larger for the 1PP task and the 3D-object mental imagery task in these patients, we can 340 rule out a general effect of attentional deficits in all tasks after left neurectomy. We interpret increased that patients with unilateral vestibular loss performed worse than healthy controls in a processing speed 345 task [START_REF] Popp | Cognitive deficits in patients with a chronic 499 vestibular failure[END_REF].

11

Relation between clinical and behavioural data 348

We only found a statistical trend for slower 3PP taking in patients with larger deficits at the presurgical 349 caloric test. This relation suggests that information from the lateral semicircular canals, or the normal 350 functioning of the structures processing this information, is involved in own-body mental rotation in the 351 yaw plane. The caloric test delivers low-frequency stimulation of the canals and assesses vestibular 352 pathways that are likely relevant for the cognitive functions tested here. Interestingly, stimulation of the 353 lateral canals by whole-body rotation influenced RTs for 3PP taking in a direction-dependent manner 354 [START_REF] Deroualle | Changing perspective: The role of 531 vestibular signals[END_REF] and caloric vestibular stimulation improved own-body mental imagery in healthy participants [START_REF] Falconer | Balancing the mind: vestibular induced facilitation of 565 egocentric mental transformations[END_REF].

355

Our data are congruent with observations in patients with unilateral vestibular disorders showing that 356 lower caloric response correlated with deficits in processing speed, memory and executive function [START_REF] Popp | Cognitive deficits in patients with a chronic 499 vestibular failure[END_REF].

357

Finally, we found no correlation between hearing loss and performance in the cognitive tasks, congruent 358 with recent findings showing similar performance in deaf signers and hearing nonsigners engaged in 359 visuo-spatial perspective-taking, 3D object mental rotation and spatial orientation tasks [START_REF] Secora | Social abilities and visual-spatial perspective-taking skill: 568 deaf signers and hearing Nnonsigners[END_REF].

361

Limitations of the study and perspectives 362

A limitation of the present study is the absence of detailed neuropsychological evaluation of the 363 participants, which could have accounted for some variability in our data. However, the mean age in our 364 sample was not high, controls were selected to carefully match the patients, and our statistical analyses 365 controlled for the effect of age.

366

The present study documents deficits of spatial cognition only in the acute stage of a unilateral 367 vestibular neurectomy. This was motivated by the need to better understand the domains of cognition 368 affected and spared when a vestibular tone imbalance is present, i.e. when compensatory mechanisms 369 are not fully expressed. There is evidence of brain disorganization in the acute stage of a unilateral 370 vestibular loss, both in humans [START_REF] Becker-Bense | The differential effects of acute 537 right-vs. left-sided vestibular failure on brain metabolism[END_REF] and animal [START_REF] Stackman | Hippocampal spatial representations require 571 vestibular input[END_REF] models. It is unknown if the deficits in 3PP taking 371 reported here vanish when patients have compensated from their unilateral vestibular disorder. Future 372 studies should endeavor to explore the postlesional recovery of spatial cognition deficits after unilateral 373 vestibular deafferentation and compare its time course to that of functional recovery.

374

As in most studies of this kind, a limitation of the present study is the sample size, which may 375 explain some discrepancies in the literature regarding the effects of left and right vestibular loss on 376 cognition [START_REF] Popp | Cognitive deficits in patients with a chronic 499 vestibular failure[END_REF][START_REF] Saj | Where is straight ahead to a patient with 522 16 unilateral vestibular loss?[END_REF][START_REF] Hüfner | Spatial memory and hippocampal volume 525 in humans with unilateral vestibular deafferentation[END_REF][START_REF] Toupet | Influence of body laterality on recovery 559 from subjective visual vertical tilt after vestibular neuritis[END_REF], in addition to the variety of tasks and procedures used. Studies remain to be 377 conducted in large samples of patients to determine the effects of left vs right vestibular loss on a large 378 range of spatial cognitive functions.

380

Conclusions 381

The present study shows that acute unilateral vestibular deafferentation impairs embodied spatial 382 cognition by disrupting visuo-spatial tasks involving mostly egocentric mental imagery (3PP taking),

383

but not object-based mental imagery. These effects were observed only in patients with left vestibular consciousness').

427

The avatar with the blue T-shirt was located either at ± 60°, ± 120° or 180° (but never at 0°, to avoid for the 3PP taking task, except that all avatars wore a white T-shirt. Thirteen participants had to press a 441 button with their right middle finger as soon as they detected a ball, or with their right index finger when 442 they detected there was no ball, and vice versa for the other participants. A fixation cross was presented 443 during 1 s before each visual scene. The correct response here is "yes", as there is a ball in the scene.

444

(D) Example of a visual stimulus for the 3D objects mental rotation. Half of the participants pressed a 445 button with their right middle finger if objects were identical, or with their right index finger if they were 446 different, and vice versa for the others. The correct response here is "no", as the objects were different.

217 219 First-person perspective task 220

 219220 left and right vestibular neurectomy (χ 2 = 1.22, P = 0.27). 218 RTs between the whole sample of patients and the controls did not differ (Mann-Whitney test, U = 244, 221 P = 0.55) (Figure 2D). Similar analyses for patients with left and right neurectomy revealed no 222 differences between the groups (left: U = 22, P = 0.15; right: U = 40, P = 0.48). As the percentages of 223 errors were very low, they were not analysed. 224 225 Visual detection task 226 RTs were significantly longer in the whole sample of patients when compared to the controls (Mann-227 Whitney test, U = 287, P < 0.05) (Figure 2D). RTs differed between the patients with left neurectomy 228 and their controls (U = 113, P < 0.05), but they were not different between the patients with right 229 neurectomy and their controls (U = 40, P = 0.63). As the percentages of errors were very low, they were 230 not analysed. 231 232

244

  than in controls for 20° (U = 269, P = 0.06), but not for 40° (U = 249, P = 0.19) and 80° (U = 260, P = 245 0.11).

  255 performance at a Bonferroni-corrected α level. The only statistical trend was a positive correlation 256 between the deficit at the caloric test measured at D-1 and the average RTs (log transform) for the 257 3PP taking task (r = 0.596, P = 0.007). No such trend was found for the correlation between the other 258 cognitive tasks and clinical parameters recorded at D-1 and D+7.

  278 perspective' of the visual scene or mixed egocentric/allocentric strategies depending on the avatar's 279 position. Debriefing questionnaires confirmed that most participants complied to the instructions and 280 used mainly an egocentric strategy. Importantly, as mixed egocentric/allocentric strategies were reported 281 in similar proportions in the patients and the controls, strategies cannot account for the different 3PP 282 taking abilities between the groups.

Figure 1 .

 1 Figure legends

425

  Participants were instructed to simulate the visuo-spatial perspective of the avatar holding the ball 426 (identified by a blue T-shirt) and from this position to toss the ball to the avatar wearing a red T-shirt.

428

  confusion with the 1PP task), resulting in a total of 5 angles of 3PP taking. The avatar wearing the red 429 T-shirt was located 60° or 120° to the right or left of this avatar. Participants pressed a key on a response 430 pad (RB-830, Cedrus Corporation, San Pedro, USA) with their right middle finger to toss the ball to the 431 right, or their right index finger to toss the ball to the left. A fixation cross was presented during 1 s 432 before each visual scene. In the example presented, the correct response is to toss the ball to the left. (B) 433 Example of a visual scene for the 1PP task showing five avatars located around a circle. One avatar was 434 facing the participants (180°), two were on their right (60° and 120°), and two on their left (-60° and -435 120°). Participants were instructed to toss the ball to the avatar wearing a red T-shirt, which was located 436 at ± 60° or ± 120° from their viewpoint (4 visual stimuli). Participants pressed a key with their right 437 middle finger to toss the ball to the right, or their right index finger to toss the ball to the left. A fixation 438 cross was presented during 1 s before each visual scene. The correct response here is to toss the ball to 439 the right. (C) Example of a visual scene for the visual detection task. Visual stimuli were the same as 440

Figure 2 .

 2 Figure 2. Influence of unilateral vestibular deafferentation on visuo-spatial perspective taking. (A)

Figure 3 .

 3 Figure 3. Influence of unilateral vestibular deafferentation on 3D objects mental rotation. (A) Mean

463Table 1 .

 1 right vestibular neurectomy (right part) together with their age-and gender-matched control participants. 464 Error bars represent the standard error of mean. (B) Box-and-whisker plots illustrate the percentage of 465 errors in the whole sample of participants. The top and bottom ends of the whisker represent the 95 th and 466 5 th percentiles of the distribution and the horizontal line inside the box represents the median. Comparison of clinical data in patients with left and right vestibular neurectomy. Means ± standard deviations are reported before (D-1) and after (D+7) surgery for each group of patients. CVS: caloric vestibular stimulation, VOR: a Independent-samples t-tests b Chi-square c Chi-square for the grade of neuroma d Average velocity of the center of foot pressure measured on a posturography platform with a stable support surface e Negatives signs indicate an ipsilesional tilt of the subjective visual vertical f The number of patients with cophosis (Cop.) is indicated; the mean hearing loss in the other patients without cophosis is indicated in brackets g Chi-square for the number of patients with cophosis a vestibulo-ocular reflex, VHIT: video head impulse test, SVV: subjective visual vertical, ipsi.: ipsilesional ear, contra.: contralesional ear, Cop.: cophosis.

Trials yielding incorrect answers were discarded from the analysis of the RTs and we excluded trials for

procedures (SPSS 25, IBM Corporation, USA). Differences were considered significant when P < 0.05.

One outlier participant was excluded for the 3PP taking task (RTs > 16 s), as well as one participant for

the 1PP and visual detection tasks, resulting in a total of 22 patients and 22 controls in the final analysis.

We used partial correlations to calculate the relation between 13 clinical parameters (Table1)

imagery in healthy participants[START_REF] Lenggenhager | Influence of galvanic vestibular stimulation 554 on egocentric and object-based mental transformations[END_REF], while only left-warm caloric vestibular stimulation distorted their

RTs in the visual detection task as resulting from deficits of alertness (because RTs were short, around

ms, whereas RTs were around 3000 ms for 3PP taking). Visual detection assessed more alertness

(reaction times) than high-level visuo-spatial cognition. Our results are consistent with data showing

loss. We believe that the present investigation helps understand the cognitive complaints of patients with

vestibular disorders. Finally, our data brings further evidence that vestibular signals contribute to several

Actions) of the European Union's Seventh Framework Programme (FP7/2007-2013) under REA grant

agreement number 333607 ('BODILYSELF, vestibular and multisensory investigations of bodilyself-

th percentiles of the distribution and the horizontal line inside the box represents the median. (D)

Acknowledgements 392

The research leading to these results has received funding from the People Programme (Marie Curie

sensorimotor bases of social cognition, including 3PP taking, and strengthens the connections between 387 the so far distinct fields of social neuroscience and human vestibular physiology (for a perspective, see 388 [START_REF] Deroualle | Toward a vestibular contribution to social cognition[END_REF]).

390

Conflicts of interest. C. Lopez serves as an associate editor of Frontiers in Integrative Neuroscience

Response times for the 1PP task and the visual detection task are plotted for the whole sample of patients.