M F Valax

E Tremblay

F Sarocchi

What month is it ? The process of temporal orientation on a unit of the year scale

The process of temporal orientation was studied in 977 subjects. They had to respond to one of the following questions : "What is (was, will be) the current (previous, next) month?", and to explain "how" they had come to answer as they did. In the majority of cases, temporal landmarks justifying the responses referred to the present, whatever the context of the question. The use of Future Landmarks increased from the beginning to the end of the month, and from the Previous Month question to the Next Month question.

Response times varied with the type of temporal landmarks, and with the question context.

On average, users of a Future Landmark responded faster. Results are discussed in relation to results of other studies using a "days of the week" scale. The different use of past, current and future landmarks supports a hypothesis that response identification depends on the functional importance of the landmarks underlying a spreading activation process.

Introduction

To coordinate their actions in line with the dynamics of their environment, individuals have to find their bearings in time. They must be able "to determine the current time and the relative times of other events with respect to some temporal framework" (Friedman, 1990, p.68). The few studies addressing this theme [START_REF] Koriat | What day is today? An inquiry into the process of temporal orientation[END_REF] ; [START_REF] Koriat | An inquiry into the process of temporal orientation[END_REF][START_REF] Shanon | Yesterday, Today and Tomorrow[END_REF][START_REF] Friedman | About time: Inventing the fourth dimension[END_REF] fit in with a functional perspective on memory for time [START_REF] Friedman | Memory of past events[END_REF]. With regard to the "week" time scale, they show that temporal orientation is based on constructing a location in time.

Several studies have shown that days of the week are easier to identify at the weekend and around the weekend than on weekdays (e.g., [START_REF] Koriat | An inquiry into the process of temporal orientation[END_REF][START_REF] Shanon | Yesterday, Today and Tomorrow[END_REF]. These findings are compatible with the ones obtained in a study on the organization of memory for the time of events, in which subjects had to remember on what day of the week an interview was held 7 to 75 days prior to the test [START_REF] Huttenlocher | Memory for day of the week: A 5+2 day cycle[END_REF]. The authors note that errors in remembering a day of the week tend to be displaced towards the middle of the week, and that errors are infrequent for the two days of the weekend. The temporal representation of days of the week thus appears to be hierarchically organized. At the first level representations consist of a "weekday" unit and two distinct units corresponding to the two days of the weekend. For the "weekday" unit a second level represents the individual days. Within this framework, problems regarding temporal orientation for days of the week mainly will occur for weekdays. Weekend days, each having a specific representation, can be matched directly.

However, some findings cannot be explained with such a hierarchical matching process. When subjects fail to identify a weekday, they tend to give a response that is close to the correct one. In most cases, this is the previous day [START_REF] Koriat | What day is today? An inquiry into the process of temporal orientation[END_REF]. If errors were due to a comparison between the temporal unit of "weekdays" and day content, the responses should be spread evenly over the weekdays. The results, however, seem to indicate an error in the updating of a previous orientation.

Such updating may depend on a spreading activation process among the units forming a network (e.g., [START_REF] Anderson | A spreading activation theory of memory[END_REF][START_REF] Rumelhart | Learning internal representations by back propagation[END_REF][START_REF] Shanon | Yesterday, Today and Tomorrow[END_REF]. Activation may depend on both external stimulation, and internal stimulation, i.e. activations spreading from neighboring cognitive or temporal units to the unit under consideration.

The main argument in favor of such a process hinges on the necessity of (almost) continuous temporal orientation. In order to adapt to the dynamics of his environment, a constant orientation of an individual is necessary. Although this may not be accurate, he/she must have an idea of "place in time". In this perspective, elapsing time is thought to be an essential factor in identifying a particular location in time. In a study investigating judgements about yesterday, today and tomorrow, [START_REF] Shanon | Yesterday, Today and Tomorrow[END_REF] found, for instance, that the accessibility of the past decreases as the accessibility of the future increases.

A number of different sources of information are likely to take part in a dynamic and constantly evolving representation of the location in time. Examples are actions and events in progress, short-term and long-term anticipations of actions and events [START_REF] Valax | Aides à l'organisation du travail dans les ateliers : problèmes du décalage entre prévision et réalisation[END_REF][START_REF] Boudes | Temporal Landmarks in dynamic situations, Second International Workshop Interuniversity Pole of Attraction on "Temporal reasoning and behavioral variability: Time and the dynamic control of behavior[END_REF], and temporally located recollections (e.g., [START_REF] Friedman | Memory of past events[END_REF][START_REF] Huttenlocher | Memory for day of the week: A 5+2 day cycle[END_REF][START_REF] Lieury | Le rôle des repères dans la récupération et la datation des souvenirs [The rôle of landmarks in the recovery and dating of memories[END_REF].

Moreover, some studies dealing with everyday work situations (e.g. [START_REF] Leplat | Les représentations fonctionnelles dans le travail [Functional representation in work[END_REF][START_REF] Weill-Fassina | Représentation pour l'action [Representation for action[END_REF] lend support to the role of intentional and contextualized representations of location in time.

The above-mentioned studies do not really enable a choice to be made between the two processess. One way of solving the problem would be to analyze the evolution of time identification for a single unit of time. [START_REF] Koriat | What day is today? An inquiry into the process of temporal orientation[END_REF] found that subjects having already mentioned today give a faster response than those who have not. In terms of a matching process, it could be assumed that the result of the identification of a particular "day" unit is stored in memory. In this case, at the beginning of the time unit studied (i.e., when it has to be identified for the first time), errors should be numerous and response times long, subsequently (i.e., when it has been identified before) decreasing and stabilizing until the end of the time unit. In terms of a spreading activation process, variations in performance would depend less on the moment within the time unit, and more on the state of the subject's representation when he is asked. In this case, time of testing would have an effect on performance only through factors determining the activation state of the target representation. We will test these processes by studying answers and response times to questions regarding the months of the year. A month is a unit of time that is long enough to justify several successive orientations. A month also has methodological advantages over a day. Firstly, physiological rhythms that may cause performance to vary during the day should not interfere over a month. Secondly, since human subjects generally sleep at night, they are inaccessible at such times. Conversely, over a month, data collection can be spread out homogeneously throughout the whole unit of time under study.

Method

Subjects

Nine hundred and seventy seven adults participated in the study. They were recruited by two experimenters in public places (public gardens, exits of cultural and social events, campus grounds, etc.), the even days of February and March 1994. Passers-by were requested to participate in a short experiment, then asked after agreement. The experimenters had approximately to balance the factors of age (20 to 60) and employment/unemployment. An attempt was made to obtain 36 subjects (18 males and 18 females) each of the 29 experimental day. This was possible each day, except on the February 8th, March 2nd and 4th (18 Ss each), on the March 6th (24 Ss) and 20th (35 Ss).

Procedure

Each subject was asked two questions, a neutral question at first ("Could you quote the name of a country whose first letter is A ?"), then one of the following experimental questions : "What was the last month ?" (PsM question), "What is the current month ?" (CM question), "What will be the next month ?" (FtM question). Each of these experimental questions was investigated three times per day, in the morning (7-9 a.m.), at midday (12 noon-2 p.m.) and in the evening (9-11 p.m.). The response time was measured using a stop-watch, triggered at the end of the question and stopped at the beginning of the (correct or incorrect) response.

After producing a response, the subject was freely asked to describe how he/she had determined the identity of the month in question. These descriptions were noted, and classified afterwards according to their temporal features as explained below.

Results

The effects of three factors were analyzed : Question Type, Date of the Month and Temporal Landmark. Levels in the first factor correspond to the three questions asked. For the Date of the Month factor, the fifteen even days analyzed were reduced to 3 categories of 5 days each, so that three levels were defined : "Beginning", "Middle" and "End" of the Month. The Temporal Landmark factor corresponds to the justification of the response.

First, we will discuss the Temporal Landmarks. Then we will analyze the results as a function of all three factors.

Temporal Landmarks

In order to justify their response to the test question, 92% of the subjects referred to landmarks (events or dates). These were classified as past, current or future. Past Landmarks refer to previous months, Current Landmarks to the current month and Future Landmarks to the following months. Current Landmarks were the most frequent (60.5%), followed by Past Landmarks (19.4%) then by Future Landmarks (12.1%).

For Past and Future Landmarks, we defined a measure for distance from the present, i.e. the deviation between the current month and the month the subject refers to.

For example, if the question "What month is it ?" is answered correctly by a subject: "This is March because next month I will be on holiday", then the distance from the present is equal to +1. Generally the distance from the present was small. The range was [-2, +5], and distances equal to + or -1 represented 86,8% of the cases. Error rate.

The error rate was 5,6%, and this was about the same for all Question Types. The number of errors depends on the interaction between the Date of the Month and the type of Temporal Landmarks used ( c2 [6]=23.8, p<0.0006). Table 1 shows that errors are frequent when subjects use Past Landmarks at the beginning of the month and when they use Future Landmarks at the end of the month. In the first case, errors are negative (responses deviated towards the previous months), and in the second case, errors are positive (responses deviated towards the following months). Relatively few errors occur in the middle of the month.

Response Times (RT)

All the correct Response Times were analyzed in a 3X3 ANOVA with Question Type and Date of the Month as between subject variables. There was no main effect of Date of the Month (F[2,913]=2.5 p<NS). Question Type, however, showed a highly significant effect (F[2,913]=40, p<0.0001). This effect is modulated by Date of the Month as is clear from the interaction between these factors (F[4,913]=14, p<0.0001). Figure 2 shows that the CM question is associated with the shortest global mean RT which is stable RT's associated with different types of Temporal Landmarks given (Past, Current, Future) were also determined. The mean RT associated with Past Landmarks is the longest (mean=1.8, SD=0.9), followed by the mean RTs associated with Current Landmarks (mean=1.53, SD=0.9). The shortest is associated with Future Landmarks (mean=1.36, SD=0.7). These means all differ significantly (F[2, 821]=5.2, p<0.006).

Discussion

The findings will be discussed from two points of view presented in the introduction section. On the one hand, we will show that, for the "month of the year" time scale unit studied, most of the obtained findings seem to be in line with a spreading activation process. On the other hand, we will use the analysis of the effect of Temporal Landmarks on performance to look at how this process can assimilate results hitherto explained by a matching process.

Previous studies on temporal orientation refer to two distinct processes : the matching process and the spreading activation one. The matching process presupposes comparing a representation of a "temporal script" (e.g., [START_REF] Huttenlocher | Memory for day of the week: A 5+2 day cycle[END_REF]) with information about the present time. In the unit of time studied here, this process should be expressed by a faster and more accurate identification of the current month in the middle or at the end of the month than at the beginning of the month, and by a homogeneous distribution of errors over the preceding and following months. According to a spreading activation process, activation is spread through a network made up of cognitive units that determine the building of a dynamic and evolving representation. It should be expressed, not through the relationship between the time of the month and performance, but through the effect of contextualized thinking on the activation state of the target representation.

Predictions derived from the matching model are not confirmed. The speed at which the Current Month is identified remains constant throughout the month with response accuracy increasing in the middle of the month and decreasing again at the end of the month. Moreover, at the beginning of the month, wrong responses refer to previous months whereas at the end of the month they refer to following months. However, although our findings do not support a matching process, the script for the months of the year, or at least the juncture between December and January probably plays a part in the process. The transfer of wrong responses to the Previous Months question does not go beyond January. Moreover, the furthest landmark in the past is the "December 31st", which is quoted by one subject alone. Thus, on the "month of the year" scale, the juncture between December 31st and January 1st seems to act as a "boundary" [START_REF] Huttenlocher | Memory for day of the week: A 5+2 day cycle[END_REF], in the same way as the weekend does on the "days of the week" scale.

As far as the spreading activation process is concerned, our findings globally agree with those obtained for the day of the week. Generally, the Current Month is identified The findings discussed so far suggest that temporal orientation is updated continuously in elapsing time. Experiences in time offer the subject memorized or anticipated landmarks that govern a dynamically evolving cognitive structure on which temporal responses are based. From such a process it may be inferred that the availability of temporal landmarks would make it easier to identify a response. In other words, the speed at which the Current Month is identified, at any time of the month, may be linked to the constant availability of Current Landmarks stored in the memory. In the same way, at the beginning of the month, the Previous Month may be identified faster than the Future Month because, at that time, Past Landmarks are more readily available. Conversely, at the end of the month, the Future Month is identified faster than the Previous Month because Future Landmarks are more readily available at that time. Although the role of this compatibility is not to be dismissed, the results suggest that the actual situation is more complex.

The compatibility between Temporal Landmarks and responses is confirmed for Future Landmarks. The closer one gets to the Future Month and the more the question focuses on the future, the more these Future Landmarks are used. Moreover, Future

Landmarks are associated with faster responses. For Current, and especially for Past Landmarks, this compatibility is less clear. In identifying the Previous Month, Past

Landmarks are used with the same frequency throughout the month, and subjects using a Past Landmark respond less quickly than the others. For these subjects, the speed of identification remains constant whatever the Date of the Month and Question Type.

We suggest that the most likely explanation of these results is that use of Past, Current or Future Landmarks does not have the same significance for the experience of time, and that subjects differ in their use of particular types of landmarks. Professional, social or even individual activities will require time to be marked out to a greater or lesser extent. A person who is subjected to considerable temporal constraints (appointments, deadlines, etc.) has a great many events located in the past, present and future, the most important of which, from the point of view of adapting to constraints, are in the future.

Conversely, for a person who is more free to manage his time, his/her activity will provide fewer events located in time, and these events will mainly concern what he has just done or experienced or what he is doing or experiencing at the moment. Because there is no obligation to adapt to time constraints, future landmarks are relatively less important. An individual would thus appear to have a sense of location in time that is more accurate the more the individual is subject to future time constraints.

  The frequency of landmarks as a function of Question Type and Date of the Month is shown in figure1. From this figure, it can be inferred that the frequency of Future Landmarks increases from the beginning to the end of the month and from the PsM to the FtM question.

Figure 1 .

 1 Figure 1. Frequency of Landmarks as a function of Date of the Month and Question Type. The relationships between Question type and Date of the Month with Past Landmarks are less clear-cut. Globally speaking, the frequency of Past Landmarksdecreases from the beginning to the end of the month. This evolution, however, depends upon the questions asked. For the PsM question, the frequency remains constant throughout the month. For the CM question, it decreases steadily from the beginning to the end of the month. For the FtM question, the frequency of Past Landmarks decreases at the end of the month. It can be noted that, at the end of the month, the FtM question favors the appearance of Future Landmarks, but it is the PsM question that most favors the appearance of Past Landmarks.Current Landmarks clearly form the majority and they seem to be independent of the Date of the Month and the Question Type.

  from the beginning to the end of the month. The mean RTs of the FtM question decrease, and the mean RTs of the PsM question increase from the beginning of the month towards the end. Subjects responded faster at the beginning of the month to the PsM question than to the FtM question ((F[1]=3.3, p<0.007). Conversely, at the end of the month, subjects responded faster to the FtM question than to the PsM question (F[1]=57.1, p<0.0001).

Figure 2 .

 2 Figure 2. Variation of Mean RT's as a function of Date of the Month and Question Type.

  faster than Previous and Future Months. At the beginning of the month, the Previous Month is identified faster than the Future Month and, conversely, at the end of the month, the Future month is identified faster than the Previous Month. Also the use of Temporal Landmarks justifying the response confirms the validity of this process. The Temporal Landmarks were studied as indicators of the events guiding the spreading activation process. This choice seems justified by the correspondence between Temporal Landmarks and the type of errors made. All subjects making a negative error (transferring the response to a previous month) cited a Past Landmark, and almost all the subjects who made a positive error (transferring the response to a future month) cited a Future Landmark.Additionally, the results suggest that the activation of representations adapts to elapsing time and to the problem posed. A majority of subjects used Current Landmarks, whatever the Date of the Month or Question Type. Moreover, the use of Future Landmarks increases towards the end of the month, and from the Previous Month question to the Future Month question. This increase is counterbalanced by a concomitant decrease in the use of Past Landmarks.

Table 1 :

 1 Number of error types related to Temporal Landmarks and Date of the Month

	Date of the Month

*Error Type

Negative : Response deviated towards a previous month. Positive : Response deviated towards a following month.


Yanni Zhou
email: yanni.zhou@insa-lyon.fr

Florin Hutu

Guillaume Villemaud

Full Duplex Spatial Modulation System Performance Depending on Self-interference Cancellation Accuracy

Keywords: Full Duplex, Spatial Modulation, Selfinterference, Channel Estimation, Bit Error Rate

Spatial modulation (SM) as a new Multiple-Input Multiple-Output (MIMO) technique is based on transmitting part of the information by activating different emitting antennas. SM increases spectral efficiency and uses only one radio frequency chain. For full-duplex (FD) communication systems, self-interference (SI) is always a central problem. Therefore, combining FD and SM can drastically reduce the difficulty of Self-interference Cancellation (SIC) because of the single SI chain. A Full Duplex Spatial Modulation (FDSM) system is proposed and an active analog SIC is highlighted in this paper. Moreover, the impact of SIC accuracy on the system performance is studied. The results demonstrate that the accuracy requirement will increase as the INR (Self-interference-to-noise Ratio) increases. The FDSM system is less sensitive than the FD system in presence of high estimated error value. Furthermore, an SI detector is presented to resolve the influence of the number of detect symbols.

I. INTRODUCTION

With the development of mobile communication technology, the number of users and data traffic in wireless communications is overgrowing. Moreover, due to the limitation of electromagnetic wave propagation characteristics, the wireless spectrum resources used to support the mobile environment can not be increased endlessly. One of the solutions to overcome this problem is the FD technology. Compared to traditional Frequency Division Duplex (FDD) or Time Division Duplex (TDD), FD can double the spectral efficiency. However, FD will bring strong SI, which severely affects the communication quality. For this reason, SIC has always been the core issue of FD development.

SM was introduced as a new MIMO technology in [START_REF] Renzo | Spatial Modulation for Generalized MIMO: Challenges, Opportunities, and Implementation[END_REF] that uses the active state of antennas as a support for the transmission of information. The superiority of the FDSM system has been theoretically studied in [START_REF] Jiao | Spatial modulated full duplex[END_REF][3] [START_REF] Koc | Two-Way Full-Duplex Spatial Modulation Systems With Wireless Powered AF Relaying[END_REF]. Since SM uses a single antenna for the transmission, there is only one data stream of SI for the receiving antenna. The implementation complexity is much lower than that of the multi-stream MIMO. Besides, the spectral efficiency can be improved compared to the FD-SISO (Single-Input Single-Output) system. As the core difficulty of FD communica-tion, SIC can be divided into passive suppression and active cancellation. Active cancellation includes analog SIC and digital SIC. Passive suppression maximizes the attenuation of the SI signal by adjusting the transmitting/receiving antenna direction or antenna position, coupling, etc. Recent research [START_REF] Bharadia | Full Duplex Radios[END_REF][6] has reduced the strength of SI to an acceptable level by combining the passive suppression and active cancellation, which makes it possible to implement a real FD radio. The key to analog cancellation is SI estimation. More precisely, a signal is transmitted as a cancellation signal, which is inverted with SI in the same frequency. The amplitude and phase of the cancellation signal are adjusted by SI estimation. After SIC in the analog domain, there is still a residual SI, which can be further reduced by using algorithms implemented in digital domain. However, digital SIC is optional. For the single SI channel as in the FDSM system, if SI estimation can be exact, analog cancellation can reduce SI to the noise level. Therefore, the SI estimation results in different accuracy of SIC, which indeed affects the performance of the whole FDSM system.

Previous studies [7][8] analyze the performance of the FD system based on analog cancellation. The performance analysis of the FD system with imperfect SIC has been presented in [START_REF] Zhan | On Design Concept For Full-Duplex Based Flexible Radio Transceivers[END_REF] [START_REF] Cagatay Cirik | Achievable Rates of Full-Duplex MIMO Radios in Fast Fading Channels with Imperfect Channel Estimation[END_REF]. However, to the authors best knowledge, few publications are available in the literature that discusses the issue of the bit error rate (BER) performance of the FDSM system. The article [START_REF] Koc | Full-Duplex Spatial Modulation Systems Under Imperfect Channel State Information[END_REF] highlights the better performance of the FDSM system compared with the SM system under imperfect channel estimation. However, it analyzes BER performance by merely defining the constant λ (0 ≤ λ ≤ 1) which represents the quality of the channel estimation.

In this paper, we propose a FDSM system over the Rician fading channel with an SI detector. More precisely, Advanced Design System (ADS) -Matlab system co-simulation will be performed in order to study the performance of the proposed system under different accuracies of SIC. Furthermore, the performance of the FDSM system will be compared with that of the traditional FD system.

The remainder of this paper is organized as follows. In Section II, the system is presented in detail. The channel model, the SI, together with the cancellation strategy, are mentioned. Section III shows the ADS-Matlab co-simulation results. Section IV summarizes the results of this work, draws conclusions, and points out future research directions.

II. SYSTEM MODEL

In this section, we describe a 2 × 2 FDSM system over a Rician fading channel with a correction module and a SIC module. Two nodes (namely Node A and Node B) with the same functions are considered. As a FD system, each node has both transmitting and receiving capabilities. The antenna used for emitting or receiving is determined by the input bit stream. The diagram of this system at Node A is presented in Fig. 1.

As we can see, the two antennas of node A will be used for transmitting and receiving respectively and simultaneously according to the input bit sequence. The system will be presented in three main parts as follows: Modulation and Demodulation part, Channel model and Channel Correction module part, Self-interference and Cancellation module part.

A. Modulation and Demodulation

Firstly, the input bit sequence is divided into N groups. Each group has log 2 (N t ) + log 2 (M ) bits, where N t is the number of antenna at each node, M is the number of distinct symbols that the transmitter is able to send. The first log 2 (N t ) bits of each group are used to select the transmitting antenna and the remaining log 2 (M ) bits are used for the QPSK modulation. We can achieve the desired spectral efficiency by using different modulation methods and configuring different numbers of antennas. In our model, N t =2, M =4, hence three bits are transmitted for each output time step. An example is given in Fig. 1, the first 3 bits of the input bitstream is 000. In this case, we active the first antenna for transmitting, and the other is connected to the receiving end. The symbol we transmit is 00, which is in the first quadrant of the constellation schema.

The demodulation process we are here talking about is the process of recovering the received bit stream after the SIC module and the channel correction module. Since we use QPSK modulation, we have only four possibilities for demodulated symbols. We calculate the minimum distance between the receiving symbol and four possibilities in order to discover the more possibly passing channel and determine the transmitting antenna. A 2 × 2 FDSM system has a total of 4 possible channels, where the receiving antenna at each node occupies two channels. The two possible demodulated corrected symbols will be compared to the four possible symbols to find the minimum difference.

Pi = min{| Yi -S1 |, | Yi -S2 |, | Yi -S3 |, | Yi -S4 |} T = min{Pi} i = 1, 2 (1)
Where S 1,2,3,4 is the QPSK symbol, Y i is the received corrected symbol, P i is the minimal difference between the 4 possible QPSK symbols and the corrected symbol which is transmitted by the i th antenna. For example, if T= P 1 , we detect that the first antenna transmits this symbol, and the first bit of this group is 0.

This detection method has already been applied in a SM system in [START_REF] Zhou | Analysis of a Spatial Modulation System over Time-varying Rician Fading Channel with a CSI Detector[END_REF]. However, the complexity is half in this FDSM system compared with that in the SM system. The reason is that only one antenna is used for receiving at each node, which reduces the number of the possible passing channels.

B. Channel model and Channel Correction module

A time-varying Rician fading channel model H is considered between two nodes. Additionally, an AWGN noise η is considered.

H = K K+1 • A + 1 K+1 • V (2)
y = H • x + η ( 3
)
where A is a deterministic matrix, V is a stochastic matrix, K is the Rician factor. More in details, K represents the ratio of the energy in the deterministic Line-of-Sight (LOS) component to the power in the aggregation of the remaining multi-paths.

Our efforts have already focused on the performance of a SM system over this channel model in [START_REF] Zhou | Analysis of a Spatial Modulation System over Time-varying Rician Fading Channel with a CSI Detector[END_REF]. It demonstrated that a lower Rician factor does not degrade the performance of the system. Instead, it increases the accuracy of the detection due to the distinct difference between channels, which brings better BER performance. Therefore, a lower Rician factor can be applied under the premise of including a channel correction module.

The function of the channel correction has also been studied. The perfect chanel state information (CSI) can be obtained under the condition that the detection symbols are enough. We already have the experience to build a SM system as well as a FDSM system with a CSI detector. However, in order to more intuitively see the impact of SIC on the system performance, we assume that CSI of the Rician fading channel can be sufficiently obtained for the channel correction module.

C. Self-interference and Cancellation module

Here, we define the power ratio of the received SI signal to the receiver thermal noise as INR. The equation that describes the received SI signal P SI is as follows:

PSI(dBm) = PS + INR -E b /N0 (4)
where P S is the power of the received signal which is emit from the other node, E b /N 0 is the signal-to-noise ratio per bit.

The SI estimation is based on the Least-Squares (LS) algorithm. The specific method is that we shield the transmitting signal from the other node. There is only one self-interference channel at a single node, from the transmitting end to the receiving end, which significantly reduces the channel estimation difficulty. The different numbers of detection symbols result in different accuracy of estimation. We can analyze the relationship between these two factors to select the best amount of detection symbols. According to the LS algorithm, the matrix of SI channel H SI is:

H SI = 1 N 2 • x t • x t H -1 • y t • x -1 ( 5
)
where x is the modulated symbol sent by the transmitting end at each node, y is the symbol received by the receiving end at the same node, N is the number of detection symbols. After estimating the CSI of the SI channel, the amplitude and phase of the SI signal can be estimated. Then, we create a signal with the same amplitude but the inverse phase as the estimated signal to perform the active analog cancellation.

III. SYSTEM PERFORMANCE

A FDSM simulator based on Keysight's ADS and Matlab software is built in order to study the BER performance. At the same time, the FD system is also simulated in order to compare its BER performance with the FDSM system. Three different scenarios will be simulated. Firstly, the effect of SI on system performance without SIC is analyzed. Secondly, we study the impact of the accuracy of SIC in the case of imperfect SI estimation. Finally, a complete FDSM system is constructed by introducing an estimated SI. A time-varying fading channel environment with K = 1 is considered in simulation. The remaining simulation parameters are gathered in Table I.

A. Without SIC

The BER performance of the FDSM system and the FD system without SIC are given in Fig. 2 and Fig. 3. We observe that the BER of the FD system is better than that of the FDSM system, which is normal because of the errors caused by detecting the transmitting antenna. When INR = -20 dB, the performance of the FDSM system can be basically equivalent to the performance of a 2 × 2 SM system. The performance of the FD system is theoretically consistent with the performance of a conventional QPSK modulation. When INR ≥ 10 dB, due to the larger SI, the BER of the two systems are maintained at approximately 0.5 while Eb/No is at a low level. In addition, we also find that the FD system is more sensitive than the FDSM system. From a poor BER to an acceptable BER, the FD system only needs a small range of Eb/No changes.

B. With different accuracy

Two factors are defined for evaluating the errors that occur in the SI estimation. The factor σ represents the difference of the amplitude between the actual SIC and the perfect SIC, expressed in dB. The factor θ represents the difference of the phase between the actual SIC and the perfect SIC, expressed in degrees of angle. We also note that although the FD system performs better than the FDSM system when there is no error or little error, as σ and θ increase, the BER performance of the FDSM system can reach the same level than the FD system, and even better. Fig. 6 shows the difference of the BER value between FDSM system and FD system for INR=40 dB under Eb/No=10 dB. The area with a value greater than zero (yellow area) represents that the BER of the FDSM system is below the BER of the FD system. This finding makes sense because it is impossible to avoid errors in the SI estimation. The FDSM system not only improves the spectral efficiency but also has a performance that is not lower than the FD system as errors increase.

C. With a real SI detector

As mentioned in section II, an essential factor affecting the accuracy of SI estimation is the number of the detection symbols. Fig. 7 gives the BER performance with real SI estimation for the different INR and the different number of detection symbols under Eb/No=10 dB.

As the INR increases, the BER of the FDSM system is slightly reduced due to the better SI estimation. This result corresponds to our previous conclusions on studying the FD system in [START_REF] Zhan | Design and Evaluation of a Wideband Full-Duplex OFDM System Based on AASIC[END_REF]. Besides, one can conclude that increasing the number of detection symbols can improve the performance of the system. However, the lower amount of detected symbols does not make the system perform poorly but at an acceptable level in the case of high INR.

IV. CONCLUSION

In this paper, a study of a FDSM system is presented. The study was performed in simulation, by using an ADS-Matlab co-simulator. We introduced different modules (antenna selection module, modulation, and demodulation, channel correction module, estimation, SIC module, etc.) in order to complete this simulation framework. The impact of SIC accuracy on the BER performance for different INRs was highlighted. We can conclude that an acceptable BER performance needs to maintain the SI estimation error within a small range. The FDSM system performs worse than the FD system when there is no error or are minor errors. However, the lower sensitivity makes the FDSM system maintain a BER performance close to the FD system and even better than the FD system in the case of large errors. Besides, the detector with the different numbers of detection symbols has a lower impact on the performance when INR is large. In other words, it is possible to reduce the number of detection symbols to improve transmission efficiency. Future work will focus on the impact of the receiver non-idealities (for example the local oscillator's phase noise) on the communication quality. Moreover, the development of an experimental setup is envisaged.

Figure 1 . 2 × 2

 122 Figure 1. 2 × 2 Full Duplex Spatial Modulation System: Node A

  The operator [ • ] t denotes the transpose, [ • ] H denotes the Hermitian transpose and [ • ] denotes the complex conjugate.

Figure 2 .

 2 Figure 2. BER performance of the FDSM system without SIC

Fig. 4 andFigure 3 .

 43 Figure 3. BER performance of the FD system without SIC

Figure 4 .

 4 Figure 4. BER performance of the FDSM system with estimation errors for different INRs under Eb/No=10 dB

Figure 5 .Figure 6 .

 56 Figure 5. BER performance of the FD system with estimation errors for different INRs under Eb/No=10 dB

Figure 7 .

 7 Figure 7. BER performance with SI estimation for different INRs and number of detect symbols under Eb/No=10 dB


Muriel Darmon

This paper aims to elucidate some of the similarities between the Bourdieusian and a psychoanalytical approach to understand the individual and the social, and to describe Bourdieu's relation to psychoanalysis. The paper begins by reflecting upon the way a research on anorexia was received and perceived by some psychiatrists and psychoanalysts. Such a case study puts into light several analogies between Bourdieu's theoretical position, his epistemological style and psychoanalysis. Then, some texts by Bourdieu, especially a discussion with the psychoanalyst and sociologist Jacques Maître, are analyzed in order to further explore Bourdieu's position vis-à-vis psychoanalysis and to assess the influence of psychoanalysis on his conception of the individual habitus. Finally, the paper discusses the possible contradictions arising between these borrowings and the principles of Bourdieusian epistemology. The paper thus suggests that the Bourdieusian approach is better analyzed as a 'sociologisation'of psychoanalysis rather than as an approach complementing or integrating psychoanalysis.

Introduction

It is not an easy task to find explicit references to psychoanalysis in Bourdieu's texts. As noted by commentators who broached this topic [START_REF] Fourny | Bourdieu's Uneasy Psychoanalysis[END_REF][START_REF] Steinmetz | Bourdieu's disavowal of Lacan: Psychoanalytic Theory and the Concepts of ''Habitus'' and ''Symbolic Capital[END_REF]) Bourdieu's texts have the specificity of being increasingly peppered with psychoanalytical terms -'unconscious, misrecognition, projection, reality principle, libido, ego splitting, negation, repression, phallonarcissism, compromise formation, and anamnesis' [START_REF] Steinmetz | Return of the repressed: the ''traumatic kernel'' of psychoanalysis in Bourdieusian theory[END_REF] 108) -but without much explicit confrontation or discussion with psychoanalysis as a disciplin. Apart from more lenghty passages in his later books, such as The Weight of the World and Pascalian Meditations, only a few quick notations or implied references can be spotted here or there. Even looking for answers in settings where Bourdieu was clearly asked about his psychoanalytic engagements does not provide the researcher with substantial material to elaborate about the connections of his work with the psy-field.

When Bourdieu participated in 1992 in the renowned workshop organized by long-time followers Gérard Mauger and Louis Pinto 'Lire les sciences sociales', he was asked by Mauger a question about the habitus and the potential resemblance between 'socio-analysis' and psychoanalysis : 'Do you analyze the way socio-analysis can work on the social unconscious the same way Freud analyzes the effects of psychoanalysis on the unconscious?' (Mauger and Pinto, 1994 : 314). Bourdieu answered without refering to psychoanalysis, but with a quick snap at the psychologisation of social problems, using in inverted commas… a psychoanalytic term ('displacement'): '[Socio-analysis] can provide people who suffer with some ways of understanding a little better what is happening to them, instead of ''displacing'' their problems, for example in the psychological direction ' (Mauger and Pinto, 1994 : 318).

Significantly, the one text that among French sociologists interested in these matters is usually thought to convey Bourdieu's position towards psychoanalysis, has not been written by Bourdieu himself and is found hidden in a book by the recently deceased Jacques Maître, both a sociologist from Bourdieu's school and a psychoanalyst, which exact reference reads : Jacques Maître, avec Pierre Bourdieu, 'Avant-Propos dialogué', in Jacques Maître, L'Autobiographie d'un paranoïaque, Paris, Economica, 1994, p. V-XXII Such a -most likely voluntary -ambiguity of position by Bourdieu, calls for clarification. This paper aims to elucidate some of the similarities between the Bourdieusian and a psychoanalytical approach and to describe Bourdieu's position. Commentators have already discussed Bourdieu's relation to psychoanalysis, but from a theoretical perspective [START_REF] Steinmetz | Bourdieu's disavowal of Lacan: Psychoanalytic Theory and the Concepts of ''Habitus'' and ''Symbolic Capital[END_REF][START_REF] Steinmetz | Return of the repressed: the ''traumatic kernel'' of psychoanalysis in Bourdieusian theory[END_REF][START_REF] Fourny | Bourdieu's Uneasy Psychoanalysis[END_REF][START_REF] Muel-Dreyfus | Une écoute sociologique de la psychanalyse[END_REF]. Instead of proceeding in a purely theoretical manner, the paper will begin by an experiment of sort aimed at grasping relations 'in practice' between Bourdieusian and psychoanalytical orientations : I will reflect upon the way my research on anorexia (Author, 2009), inspired in part by Bourdieu, was received by psychiatrists and psychoanalysts. Such a case study will display (and not merely discuss) the affinities between Bourdieu's sociology and psychoanalysis. Then, I will draw from the discussion Bourdieu had with the psychoanalyst and sociologist Jacques Maître to describe Bourdieu's position, and assess the influence of psychoanalysis on his conception of the individual habitus. Finally, the paper will discuss the possible contradictions arising between these borrowings and the principles of Bourdieusian epistemology, especially its definition of a sociological right to scientific imperialism and its repeated claims about the 'social' nature of the conscious and the subconscious at the individual level. The paper suggests that the Bourdieusian approach is better analyzed as a 'sociologisation' of psychoanalysis rather than as an approach subordinated to, complementing or integrating psychoanalysis. The study I wish to present briefly here (since it is not the primary focus of the article, but an illustration of the arguments that follows) is a qualitative research on anorexia. The idea was to propose a consistently sociological way of looking at what is most commonly seen as a 'psychological' and 'pathological' state. As a sociologist, I wanted to study anorexia empirically, through fieldwork. I did not want to limit my scope to the various contexts of anorexia (historical or social), but rather to try and show what a sociological eye could bring to the study of anorexia itself, or anorexia 'in practice'.

In her groundbreaking book on the social history of anorexia, Joan Jacobs Brumberg distinguishes between the questions that can be raised and answered by social scientists (such as the history of the diagnosis, the sociocultural context of the pathology, the analysis of its specific recruitment) and those which could not, namely 'the subsequent "career" as an anorexic [which is] obviously the concern of medicine and mental health professionals ' (1988: 38-40). My study fails to comply with such division of labour between disciplines. Such an approach of 'anorexia in practice' is all the more necessary, given that the vast majority of social sciences or gender studies of anorexia is concerned with the various discourses on anorexia (be that the medical, the popular, or the anorexics' discourses) or with what anorexia 'symbolizes' or 'means' [START_REF] Bordo | Unbearable weight. Feminism, Western Culture, and the Body[END_REF][START_REF] Turner | The Body and Society. Explorations in Social Theory[END_REF], and thus take little interest in the anorexic activity itself, with sometimes no other data than secondhand material. Another way of putting it would be to say that, instead of jumping to posit an anorexic subjectivity or an anorexic ontology, even a socially constructed one, I first want to study sociologically 'what anorexia is' through what anorexics do. This is why I use the notion of (deviant) 'career' to 'turn people into activity' [START_REF] Becker | Tricks of the Trade. How to think about your research while you're doing it[END_REF], and to shift from a definition of 'identity' to one of action: one is not born an anorexic, one must become one, and to 'be' (labelled) anorexic, one has to 'do' certain things.

It focuses on anorexic

I do not, however, stop at the sequencing of the anorexic career, and I try to extend the analysis. To 'do' those things, you have to 'be' someone specific:

what do the people who are doing those things 'have to be' to do what they're doing? In the traditional interactionist use of the notion of career, the social proprieties of the individual are neglected (or even refused) as explanatory, i.e.

as reasons to enter a deviant career. As far as anorexia is concerned, this seems rather problematic, since the recruitment of the pathology is both specific and enduring: the vast majority of anorexic patients are adolescent girls from uppermiddle to upper classes [START_REF] Mcclelland | Anorexia and Social Class[END_REF], as happened also in my own study where I defined class membership based on both parents' and grandparents' occupations and diplomas (Author, 2009) [START_REF] Bourdieu | La Distinction. Critique sociale du jugement[END_REF]. In my perspective, these social properties are indeed taken into account, but in a second step, and as social conditions of possibilities of the anorexic career. The This is why my study of anorexia is structured in two different and successive moments, and combines an approach of the anorexic career with a study of the anorexic habitus (Author, 2009). What is important for my demonstration here, is the fact that the book this study gave birth to, published in 2003, is clearly divided into two parts, related to the 'career', as in the interactionist approach, and to the habitus in social space, as in the Bourdieusian approach.

The first part offers a reconstruction of the anorexic career, based on an interactionist approach of deviance, and describes the anorexic activity as a selfconversion work. The second part of my work (and of the book) on anorexia is the analysis of the anorexic habitus and its social space. The set of practices that constitutes the anorexic career are located in a specific place within the social space. For example, what the interviewees eat and what they don't eat is not chosen randomly, or only according to the calorie intake of each food. Food selections reveal 'dominant tastes' [START_REF] Bourdieu | La Distinction. Critique sociale du jugement[END_REF] for they single out foods that are consumed in greater amounts by upper classes still today in France (fruits and vegetables, fish and seafood, yoghurts…). Anorexia is therefore not only about 'restricting' food: it is about choosing a certain type of food, with certain properties, both caloric and social. And this is done at the expense of other foods, which are strongly associated with working-class tastes, such as bread, charcuterie, or plats en sauces. Anorexia is therefore an extreme but relevant case in point to show the enduring social class distinctions of eating practices, tastes and distastes [START_REF] Wills | The framing of social class distinctions through family food and eating practices[END_REF][START_REF] Rhys-Taylor | Disgust and distinction: the case of the jellied eel[END_REF]. More generally, anorexic food practices, body practices and school practices, however weird or pathological they may appear, echo those of the upper and middle classes from which comes the majority of anorexic patients. They therefore reveal the construction, at the result of the conversion work of the anorexic career, of an anorexic habitus which can be located within the social space of social classes.

This summary of my results aims at showing that the interactionist deviant career orientation and the Bourdieusian one are, to a large extent, separated in the book, and this is also how I am used to present my arguments: in two distinct 'moments'.

Another duality must be mentioned, regarding the settings of the research. It was conducted in France and based on repeated in-depth interviews with 14 anorexic patients from different hospitals and five months of observations of the everyday life and talk therapy sessions in the units they were hospitalized in, together with interviews with some of their teachers (11 interviews), snowball interviews of formerly diagnosed anorexics (three) and comparative interviews on body and food practices with high-school girls (11 interviews).

The persons interviewed as anorexic patients were all adolescent girls, and were all from upper and middle classes (Author, 2009). More precisely, the research was conducted in two different hospitals, representative of two antagonistic 'approaches' to anorexic treatment [START_REF] Luhrmann | Of Two Minds[END_REF] within psychiatry. The first hospital was of a biomedical orientation : in spite of the differences or even conflicts between the members of the medical teams, they believed in a multifaceted explanation of anorexia where biological factors were prominent, had no difficulties in using profusely the official diagnostics and diagnoses manuals, and were used to prescribe drug therapy (combined with a behavioural and cognitive approach) at the core of the treatment. The second hospital was, conversely, of a psychodynamic and psychoanalytical orientation: I shall focus in this paper on the case of the psychoanalysts' responses to the Bourdieusian analysis, linking the 'anorexic habitus' part of my research and the psychoanalytic orientation, because this is a productive means to engage the discussion I wish to develop about Bourdieu's relationship with psychoanalysis. Therefore I will only mention here that the biomedically oriented psychiatrists had many reasons to feel closer to the deviant-career part of my work, which they favoured and spontaneously understood, and to partake in its criticisms of functionalism but also psychoanalysis [START_REF] Becker | Personal Change in Adult Life[END_REF].

On the other hand, psychoanalysts and psychoanalytically-minded psychiatrists clearly favoured the arguments, results and findings of the Bourdieusian part of my book -the anorexic habitus -, both because of what the approach was up against and because of what it stood for, as I will show now.

Psychoanalysts approved my choice of drawing from a Bourdieusian approach in my study of anorexia, first because it meant critizising a 'descriptive' approach of the anorexic career and studying the individual predispositions that make the progression into such a career possible. The description of the anorexic career in the first part of my book was inspired by a

Beckerian definition of a deviant career [START_REF] Becker | Outsiders[END_REF][START_REF] Becker | Tricks of the Trade. How to think about your research while you're doing it[END_REF]: the reasons or causes to enter the career are not to be taken into consideration, the question being 'how' people engage in a particular activity and not 'why' they do it.

Whenever I presented results from my study and the reasons to go from Part I (the anorexic career) to Part II (the anorexic habitus), I argued that the career approach was missing the fact that 'not everybody' had the same probability to enter into an anorexic career or stay on its path, and that the anorexic activity actually presupposes some class predispositions that can account for the specifity of the upper-class recruitment of the pathology (Author, 2009).

This actually loosely resembled how psychoanalysts criticize behavioural Within us lies in various proportions Yesterday's man. And it is even him who is predominant in us, since present is but a very small thing compared to this long past where we were formed and from which we result (…) Yesterday's man is the unconscious part of ourselves. (Durkheim, 1938: 18-19) As Francine Muel-Dreyfus (2003 : 228) puts it, Bourdieusan sociology, as psychoanalysis, 'gives a great deal of room for the uncouscious' and 'must fight against the amnesia of genesis which eternalizes and reifies concepts and categories, thus naturalizing the social'. This is why my quest for 'Yesterday's woman' within anorexic patients and my various invocations of the social past of patients as explaining their conduct -be that the individual past of the socio-genesis of a given habitus, or the collective past of history -always resonated strongly with the psychoanalytical audience. It was the case whenever I threw light upon today's anorexia with a reference to the construction of the modern 'universe of class bodies' (the social hierarchy of bodily shapes and styles) [START_REF] Bourdieu | La Distinction. Critique sociale du jugement[END_REF] Similarly, the interviews displayed a more general ethos of control over social destiny which appears also to be connected with a specific class socialization (Author, 2003(Author, , 2009)). The fact that I did not resort to the usual psychological explanation of the 'urge for control' (supposedly typical of anorexics) did not prevent psychoanalysts to feel familiar and attuned to the idea of explaining such a behaviour within a family past, even if the strong point of my explanation related to a social class past.

To summarize what I want to draw from this account of the presentations of my research to psychoanalytic inclined audiences: my argument is that these manifest preferences both for what a Bourdieusian approach criticized (the epistemological choice of 'description' and the obliteration of the past) and provided (causal explanations of behaviours and attention to individual and group history) are not a coincidence, but proceed from the 'elective affinities' between the Bourdieusian and the psychoanalytical approach, and their respective positions within the fields of sociology and psy-fields or particular branches of medicine. Between the two main sociological orientations I presented -the interactionist deviant career and the anorexic habitus -, the psychoanalytic audience 'chose' the one that most resembled its own (Bourdieu was embraced as a sociologist they could 'think with') and the one that was opposed to a kind of sociology -the interactionist -that resembled a psychiatric position they were up against (Bourdieu was also embraced as a sociologist they could 'criticize with').

A 'pas de deux' between sociology and psychoanalysis

Once experienced and delineated, the proximity I found between Bourdieu and psychoanalysis can appear quite self-evident. This makes all the more surprising the very small number of explicit references to psychoanalysis made by Bourdieu in his books over the years, with the exception of some more explicit engagements in his later writings -The Weight of the World and Pascalian Meditations.

In The Weight of the World, published in French in 1993, the word 'Psychoanalysis' appears twice in the Index -which is rare, the word seldom appears in Bourdieu's other indexes. ii Psychoanalysis is mainly discussed in the last two pages of 'The Contradictions of Inheritance', a text written by Bourdieu, where Freud is quoted once. But we note that this discussion begins with a very striking statement: 'This is not the place to question the relation between the mode of exploring subjectivity proposed here and that practiced by psychoanalysis' (Bourdieu, 1999: 512).

In Pascalian Meditations, published in French in 1997, 'psychoanalysis' does not figure in the Index rerum (Freud is referenced four times in the Index nominum, though), but 'psychological operations', described in explicit psychoanalytic terms (projection, identification, transference, sublimation, etc.) are discussed more extensively in the book and especially in the first pages of Chapter 5, called 'Libido and illusio' (Bourdieu, 1997: 197-201).

I will return to the content of these texts, but let me just note now that, all in all, the explicit discussions of psychoanalysis by Bourdieu do not amount to much given the 'obvious' proximity referred to above and compared, for example, to the way Bourdieu deals with history, or with economics, in his books. Among

French sociologists interested in the connections between sociology and psyfields, the advice given to academics looking for more has always been to read a text, not written by Bourdieu himself, but which is supposed to convey 'his' position on the subject of psychoanalysis. This text is the preliminary section (called an 'Avant-propos dialogué', 'Foreword in the form of a dialogue') of L'Autobiographie d'un paranoïaque by Jacques Maître, published in 1994.

Since this book is not translated into English, let me present in some details the content of its preamble. It is indeed cast as a dialogue between Bourdieu and Maître, of which I will discuss three important themes : the question of the dialectics between instincts and institutions, the difference between 'institution' and 'field', and the affinity with psychoanalysis as an acquired right for Bourdieu's sociology following years of what he calls 'repression'.

The dialectics between instincts and institutions

Bourdieu begins by praising Maître for having chosen to conduct a methodical and scientific enquiry on subjects usually tackled in essays, such as the relationship between sociology and psychoanalysis, and more specifically, the question of the cathexis (investissement) in institutions -Maître had mainly studied the religious institution and Christian mysticism. According to Bourdieu, the various cases studied by Maitre (such as Sainte Thérèse de Lisieux, or Madeleine Lebouc, a patient of the nineteenth century psychologist Pierre Janet) make it possible to see 'how dispositions (as potentialities) are actually related to certain institutions, or, better, certain fields (as array of possibilities); how social agents exploit institutions to satisfy their instincts (pulsions) (…), and how institutions, conversely, make the social agents' instincts serve their own ends' (Maître and Bourdieu, 1994: VI). iii Later in the text, Bourdieu elaborates on the 'general dialectics' between the individual (ie, in this text, his or her dispositions, instincts, personal history) and the institution: 'the investment in the institution and the investment by the institution, coercion and adhesion, etc.' (Maître and Bourdieu, 1994: IX). Social agents, 'depending on their personal history and therefore their dispositions', select some of the meanings offered by the institution. The institution itself offers a 'space of pre-processed possibilities. It regulates dispositions: it constraints and censors them at the same time that it opens routes to them' (Maître and Bourdieu, 1994: VI).

Maitre agrees with Bourdieu's theoretical proposition that a dialectics exists between individual and institutions, and links his own work to Bourdieu's sociology:

In The Rules of Art, you said the field was providing social agents with a legitimate form to fulfill their wishes (désirs), and the phrase got me thinking. When one speaks of 'wish' (désir), one can be on psychoanalytical grounds, but from the moment one speaks of legitimacy, of field, one is on the sociological side. Knowing how this negociation between wishes and legitimacy works for each person is the crux of the matter. (Maître and Bourdieu, 1994: VII) They then discuss some of the cases studied by Maître, as instances of relationships between instincts and institutions, and Bourdieu concludes again by remarking on the dialectical relation between the two. People, who have specific 'interests', 'instincts' and 'wishes linked with their family history', 'choose' some institutions because these institutions can provide them with ways of expressing or satisfying these instincts; but conversely, institutions 'choose' people, redirect and manage their instincts:

In the process through which somebody becomes a professor, for example, [the negociation between the instincts and the institutions] is a very long one; it begins in middle school: the pupil who seats in the first row, who raises his hand to speak, chooses the institution and is chosen by the institution because he chooses it. One can't tell which chooses which, if the institution chooses the individual or if it is the other way round. [START_REF] Maître | Avant-Propos dialogué[END_REF]: VIII-IX) acknowledges that Bourdieu is 'right to criticize [his] excessive use of the term ''institution'' because it gives the wrong idea of monolitism' (Maître and Bourdieu, 1994: XII). Bourdieu concludes this line of discussion by reaffirming the superior value of the 'field':

The notion of ''field'' is useful in that it makes it possible to say that there is unity, within a field, ''in'' and ''through'' conflict. What unites people in a given field is conflict. They agree to disagree over the monopoly of something, and they are therefore bound by what divides them (…) The fields' elasticity is huge, and I think fields end up being much more pervert than apparatuses (les champs sont beaucoup plus pervers que les appareils), because they allow so much more. (Maître and Bourdieu, 1994: XII) As it is clear in this last sentence, the criticism of the psychoanalytical use of the term 'institution' has nonetheless a conciliatory connection with the psychoanalytical characterization of the field as 'pervert'. This move, 'two steps forward, one step back', is, as we will see, a recurrent move used by Bourdieu to temper his objections against psychoanalysis, as soon as he utters themonce again a rare courtesy, which Bourdieu never extended to economics, for example -: the dialogue with Maître is indeed a pas-de-deux iv .

The 'guts to transgress'

This 'affinity' approach, made of conciliation and correspondences between sociological and psychoanalytical terms, is given a new meaning later in the discussion. Bourdieu claims that such an affinity is an acquired right for him, because he had to overcome the 'collective positivist repression', dating back to the nineteenth century, which forbade him, as a sociologist, to acknowledge this proximity :

[In Janet's time], there was this collective repression, with a prevailing scientism. When I read again the Durkheimians -God knows they are still overwhelming, and we wish we would live up to them -it seems to me there is one thing for which we have made huge progress compared to them, and it is in reflexivity (…) The same goes with Marx, who was very good at 'psychoanalyzing' others, but not very reflexive (…). Saying

[in The Weight of the World] that an interview was a spiritual exercize was hard. I have always thought that, I have always felt it. But there was this kind of positivist repression (refoulement positiviste): a questionnaire must be scientific (rigoureux), objective, neutral, there's no cathexis (investissement)… You must also have known this form of masochism, which passes for professional virtue. I had to wait to be the age I am now, and to have the social guts (culot social) that come with it, to be able to transgress like that. [START_REF] Maître | Avant-Propos dialogué[END_REF]: XIV-XVIII)

By refering to his current 'social guts', Bourdieu states that his consecrated position in the field of sociology in 1994 had allowed him to break with old habits, both individual and collective, regarding what was deemed scientifically proper in a field inherited from nineteenth century French sociology.

A thirty years relationship, from repression to transgression ?

The implicit history contained in Bourdieu's last quotation could be understood more precisely as follows: from an adhesion to -or an impossibility to explicitly defect from-a positivist repression, Bourdieu would have been increasingly able, through reflexive work in particular, but also self-confidence, to embrace his inner affinity with psychoanalysis and to call for a 'socioanalysis' as a way to 'trully go beyond the opposition between psychoanalysis and sociology'.

From an imperialist sociology to a call for unity ?

Apart from Bourdieu's reluctance to assimilate 'fields' with 'institutions', and also a short passage to which I will return, the 'Avant Propos dialogué' could be read as bearing witness to the process of bridging the oppposition between sociology and psychoanalysis, and as constituting a decisive shift from Bourdieu's original epistemological stance on this matter.

In Le Métier de sociologue -the building blocks of Bourdieu's epistemology written in collaboration with J.-C. Passeron and J.-C. Chamboredon -a

Durkheimian stance is adopted and defended:

Durkheim's moto [one must explain the social by the social and by the social only] recalls the methodological decision not to prematurely give up the right to sociological explanation, or rather, not to adopt a principle of explanation borrowed from another science, be that biology or psychology, as long as the efficiency of purely sociological methods of explanation has not been fully tested. (Bourdieu et al., 1968: 35) Even if it does not mean that sociology has the 'intention to explain sociologically each and every aspect of human reality' (Bourdieu et al., 1968: 35), such a Durkhemian stance is still very far from a call to go beyond the opposition between psychonalysis and sociology.

Moreover, Le Métier de Sociologue states very strongly that sociological concepts have their own meaning, and that no 'correspondence' between these and others from different disciplines (like the ones used in the dialogue with Maître) is to be made. For example, Bourdieu suggests as 'a good method' never to speak of 'the unconscious' of social agents, but rather of what they do 'without knowing it', 'without being aware of it', 'unconsciously', etc. 'The unconscious' is in the text clearly referred to as psychoanalysis, as 'another tradition', which uses it 'with another meaning', not a sociological one. In Le Métier de sociologue, both Durkheim (who stated the difference between the 'unconscious' as a particular psychic agency and the existence of patterns of behaviour people are not conscious of) and Wittgenstein (who insisted on the difference between saying 'I have a toothache without knowing it' and 'I have an unconscious toothache') are summoned to suggest and to explain the difference -the opposition -between sociology and psychoanalysis as far as this is concerned.

There is no analogy here between psychoanalytical and sociological terms, but a clear distinction is made between 'the unconscious as a specific psychic agency', as assumed by psychoanalysis, and 'the existence of patterns of conduct that people are not aware of' studied by sociology (Bourdieu et al, 1968: 152-153).

Finally, even when Bourdieu quotes an idea by Bachelard of a 'psychoanalysis of the scientific mind', it is not without an immediate affirmation of the need 'to expand' it through the sociology of knowledge and an analysis of the social conditions in which sociological research is conducted (Bourdieu et al, 1968: 14), thus stating clearly sociology's prominence and independence.

Thirty years later in the discussion with Maître, the general tone found in Bourdieu's works is very different. It is also different in the two of his major texts that we have singled out earlier, The Weight of the World and Pascalian Meditations, where he appears to be dealing more explicitly with psychoanalysis.

First, The Weight of the World manifests a different way of relating with 'interviewees' and a different relationships between the interviewees' discourse and the scientific discourse of objectification -this is apparent in the discussion with Maître, where Bourdieu speaks of this book as a transgression regarding the 'positivist repression'. More particularly, one of the short texts written by Bourdieu within it, 'The contradictions of the inheritance' (Bourdieu, 1999: 507-513), makes many references, implicit or explicit, to psychoanalysis, for example when referring to 'transgression' , 'reality principle', 'identification' ('The son's identification to the father's wish to be continued…' ), the 'real' and the 'ideal', 'ideal ego', 'substitute' ('the son or the daughter constituted as the father's substitutes' ), 'projection', 'regression', 'murder of the father' (by social mobility)… The theory of the cleavages of the habitus (see other contributions in this Special Section) is indeed rooted in this extended use of psychoanalytic terms and lines of reasoning.

Likewise, in Pascalian Meditations, the section 'Libido and illusion' deals with a classical sociological question (the relationships between primary and secondary or 'specialized' socializations) by stating that the conversion of dispositions, when an individual enters a field, has to do with 'a series of imperceptible transactions, semi-conscious compromises and psychological operations (projection, identification, transference, sublimation, etc.).' (Bourdieu, 1997: 197). Freud's analyses about 'compromise-formation' and 'organization of the libido' are explicitly referred to, in order to study a domain where Bourdieu could obviously have used sociological concepts -and Bourdieusian ones, for a start. Even more strikingly, sociology and psychoanalysis are put at the same level:

The original form of illusio is the investment in the domestic space, the place of a complex process of socialization of the sexual and sexualisation of the social. Sociology and psychoanalysis should unite their strengths (but to do so they would need to overcome their prejudices against each other) to analyze the genesis of investment in a field of social relations. (Bourdieu, 1997: 198-199) The symmetry between 'the sexual and the social' seems a recurrent way for

Bourdieu to talk about the relationships between sociology and psychoanalysis, a synecdoche even, since it was already the case in the Avant-Propos dialogué :

The world of mathematics, for an adolescent, is a world of purity, of gratuity, which makes it possible to free oneself from the sexual and the social ; one should do a kind of social psychoanalysis of the choice of hard sciences as a way to distance oneself from existential problems, sexuality, but also everything that is linked with the social. (Maître and Bourdieu, 1994: XIV) Going thirty years ahead, the dissymmetry that Le Métier de sociologue was striving both to manifest and to establish -with its definition of a sociological point of view as specific, or even as transcendent (exterior, and superior) -seems indeed to have given way to symmetry (the sexual and the social, sociology and psychoanalysis…) and correspondences (dispositions are equivalent to instincts, the field is almost an institution…).

Return of the repressed

But such a history -that of a sociologist progressively freed from his prejudices towards psychoanalysis, or rather made free to express his intellectual affinities -is not the whole story. And even the texts studied here can tell a different story if closely scrutinized.

Let us go back first to 'The contradictions of the inheritance', in La Misère du

Monde. The text ends with two pages, displaying a general overtone much different from earlier formulations:

One should be careful not to see the family as the ultimate cause of the distress it seems to cause (…) Behind the story of the most ''personal'' difficulties and of apparently strictly subjective tensions and contradictions are often expressed the deepest structures of the social world and their contradictions. (Bourdieu, 1993: 716) When Bourdieu explicitly defines the relationships between sociology and psychoanalysis, he does so by refusing to see them as alternatives to each other perspective, psychic processes do exist, but what is important for the sociologist is to look at what the social order does to them :

A true sociogenesis of the dispositions that constitute the habitus should be concerned with understanding how the social order collects, channels, reinforces or counteracts psychological processes depending on whether there is a homology, redundancy, and reinforcement between the two systems or, to the contrary, contradiction and tension. (Bourdieu, 1999: 512) Then, even if 'it goes without saying that mental structures do not simply reflect social structures', Bourdieu insists on how the field influences wishes, and converts them into 'specific illusio' and socially approved forms. He thus focuses on one aspect of the dialectics between instincts and fields: the sociological direction of causality. Bourdieu hammers this point in by mentioning Freud's analysis of the family romance, in which daydreams can serve two ends: the ambitious goal and the erotic one, the latter, according to Freud, being often hidden behind the former. Bourdieu then adds : 'It is not up to me to confirm or deny Freud's affirmation. But I would like to recall the complementary affirmation that psychoanalysis overlooks : wishes manifest themselves within each field only under the specific form that the field assigns to them at a given moment in time and which is, more often than not, that of ambition.' (Bourdieu, 1993: 718). The social 'form' of ambition is therefore not a mere smokescreen, or a mask behind which the erotic would be hidden: the The understanding of sociology as a science which may use the same data and objects as psychoanalysis -but is to look at what psychoanalysis overlooks, pushes aside as details or smokescreens, or fails to grasp -is therefore much closer to the epistemology of Le Métier de Sociologue. The idea that the social 'forms' given to psychic or psychological processes are indeed part of these processes, make them exist in a certain way and not only shape them, is similarly a strong sociological standpoint.

Such a standpoint suggests that the Bourdieusian approach vis-à-vis psychoanalysis is better understood as a sociologisation of psychoanalysis -an 'annexation [of psychoanalysis] through the sociological treatment of certain of its concepts' (Fourny, 2000: 103) -rather than as a complementary or integrated approach. To exemplify such a position, I will briefly go back to my own research on anorexia and show the way some of its results are in line with it.

First, such a sociologisation means that objects are to be chosen and constructed within the sociological approach itself, even when they seemingly 'belong' to another disciplinary realm. For example, my focus on 'anorexic practices', on what young girls labelled as anorexics actually do, comes from a sociological interest both in individual activity and social practices (as situated in social space), which can be opposed to the psychological or psychoanalytical tendency to overlook such practices as mere symptoms.

Second, the sociological stance detailed above entails explaining, as Durkheim's moto goes, 'the social by the social' and therefore looking at the chosen objects with our own sociological gaze. This is where I depart strongly from George Steinmetz's views regarding Bourdieu's position but also more generally about the relationships between sociology and psychoanalysis. For George Steinmetz (2006: 453) -who calls upon Vincent de Gaulejac -Bourdieu 'did not recognize that Freudian/Lacanian theory could help him to avoid the problem of « sociologism », that is, of reducing the process of the « incoporation » of the social into the individual to (…) logics of social power'.

With the 'first' Bourdieu of the Craft of Sociology, but even also, as I have tried to

show in this article, with the 'late' Bourdieu of the 1990's, I fail to see where the problem is for sociologists to be sociologists and to practice 'sociologism' -a criticism often uttered against Bourdieu by rational choice sociologists. For example, anorexic patients are well-known for their 'non compliance' to the hospital's requirements and point of view, and for their 'resistance' within the psychological or psychoanalytical sessions. This resistance is generally interpreted as psychological and is linked to mental pathology. Without endorsing this view, I tried to look at such resistance as a social will and way of acting, made possible by distinctive class resources. I showed that the specific ways in which anorexic patients resist medical power is not absent of social class dispositions and attitudes, such as self-assurance, a sense of entitlement, familiarity and connivance with the medical world, or a relation to 'speech' and discourse that comes with a high level of cultural capital (Author, 2003(Author, , 2009)).

Similarly, instead of trying to answer the question of gender the way it is framed by psychology (as a refusal or a denial of femininity, for example), I

showed that anorexic practices are extreme forms of typical practices of women from the middle and upper classes, and that hospital work can be interpreted as an enduring work on patients destined to 're-feminize' them, which is oriented by and towards a specific definition of middle-class (and not upper-class) femininity (Author, 2003(Author, , 2007)).

More generally, I showed that the anorexic career is both made possible by the social properties of the young girls who engage in it and oriented towards the upper regions of social space and a specific definition of social excellence (Author, 2003(Author, , 2009)). In Bourdieu's terms, quoted above, this comes down to showing that 'wishes manifest themselves within each field only under the specific form that the field assigns to them', or that fields 'constitute' and 'create' wishes and not only offer them possibilities of expression. In all these instances, what we see is the way the social world, as a space of possibles, 'socializes libido', even in its 'pathological' forms. To me sociology has much to gain from this kind of confrontation with 'unusual' objects, as long as, to paraphrase Spinoza, it strives to persevere in its disciplinary and epistemological being. But such studies can also benefit the general knowledge of these objects, as an 'unusual' way to look at them, which can possibly bring out new elements.

Conclusion

A sociological analysis of Bourdieu's relationships to psychoanalysis would require, most evidently, an analysis of their relative positions within the academic field, together with a sociological account of Bourdieu's trajectory, position, dispositions and stances. As much as I acknowledge that this would be most desirable, this paper never had such an intention. Its aim has been to address some very particular questions: (1) What could account for the discrepancy between the blatant elective affinities between socioanalysis and psychoanalysis and the very few explicit discussions of psychoanalysis by Bourdieu ? (2) How can we characterize Bourdieu's few explicit claims about the connections between these two fields of academic enquiry over the years ?

(3) Do they tell a specific history of connection between these two fields, from When sociology tackles realities that psychoanalysis also considers, it should, therefore: (1) choose its own objects: for example, look at aspects of realities which psychoanalysis deems unimportant or considers as mere defenses, (2) look at them with its own gaze: for example, not look for the sexual behind the social but for the social behind the sexual, decipher the social structure that lies under family past, and more generally hold that the 'social' is not a mere form, or language, or smokescreen, but that it is, within a sociological approach, the stuff that reality is made of. In contrast to the psychoanalysation of sociology that socioanalysis often involves, such a sociologisation of psychoanalysis seems beneficial to sociology, but it would also ensure a more fruitful, equal and complex pas-de-deux between sociology and psychoanalysis.

depiction of the phenomena and even hint at its strategic and very conscious dimension -Bourdieu being well-known for his disciplinary reflexivity and the constant strategic maneuvers in his texts (quoting and not quoting, elevating, ridiculing or ignoring, expliciting alliances and oppositions or keeping them implicit…) (Encrevé, Lagrave, 2003).

5 For a different interpretation of this sentence -Bourdieu failing to see that sociology and psychoanalysis 'were not alternatives, but that psychoanalysis filled some of the lacunae in his own theoretical approach'see (Steinmetz, 2006: 459-460).

  a clarification of the terms of engagement of Bourdieusian thinking about psychoanalysis through a reading of Bourdieu's texts, I introduce my argument empirically by focusing on the ways in which a sociological study I conducted was received and perceived by a group of psychoanalysts to whom I presented it. Such a tiny and, except for me, unimportant experience is indeed a way to put into light the 'hooked atoms of the field' i between Bourdieu's theoretical position, his epistemological style and psychoanalysis.

  day-to-day practices and representations, on what happens during anorexia, on what anorexics actually do, and not on what they represent or symbolize.

  interviewees' habituses, which I study, is both what makes the anorexic career possible and what is modified along the various phases of the career, as a result of a specific work of self-transformation performed by the anorexics.

  the teams looked for causes of anorexia in the patients' past, family past and family dynamics, medics were reluctant to use official diagnostics classifications, interpreted the biological and practical manifestations of anorexia as mere symptoms, and used talk therapy as the main and most recognized course of treatment. Over the years, I presented my study in both institutions, as well as in a dozen of other medical settings, broadly belonging to one or the other of the two therapeutic orientations. It is from these presentations of two different kinds of sociology to two different kinds of psychology, that I draw the 'impressions' and the data -or 'quasi-data', since I cannot claim to have performed a real sociological study of reception -that I use here.To put it in a nutshell, each part of my research -which I labelled according to their main sociological allegiance as the 'anorexic deviant career'

  psychology and biological approaches, as only focused on a 'symptom', and as lacking historical depth in the study of the individual. Psychoanalytical audiences also approved of the epistemological shift entailed by moving from Becker to Bourdieu, because they perceived it as switching from description to explanation, from the given to the hidden, from a pragmatically-viewed present (what people are doing) to a deterministic and enduring past (what people are, or have to be, to do what they do). As I argued that social conditions of possibilities were necessary to enter the anorexic career, and that statistics showed that two-thirds of the patients come from the upper classes, they heard that 'studying the symptom ' without taking into account the psychic construction of the individual during childhood and adolescence leads to only a partial apprehension of the anorexia phenomena.In a more positive manner, the psychoanalytic audiences often exhibited interest in the core Bourdieusian idea of the influence of primary socialization, of the persistent making of the individual within the first years of his or her existence. The Bourdieusian approach evidently shares with psychoanalysis a principle summarized in a sentence by Durkheim often quoted byBourdieu (1980: 94) :

  at the end of nineteenth century, when thinness and emaciation went from stigma of poverty to status symbols and attributes of the 'leisure classes'(Author, 2003). It was also the case whenever I took into account the individual past of the socio-genesis of a given habitus. The anorexic patients I interviewed displayed social dispositions that could be related to their middle-and upper-class upbringings. Manifestations and proofs of the weight of the social past of their class socialization on their present behaviour were always welcome by the psychoanalytic audiences, both as familiar and as complementary with their own point of view. This was for example what happened whenever I presented my analyses of the anorexic ethos of 'control' over corporeal destiny -the body can and will be transformed -and showed it was characteristic of middle and upper classes and in contrast with a more fatalist body acceptance in the working classes.

  social context -the field -is what makes wishes manifest themselves in a particular way and exist at a given moment of time and in a given individual.A small passage of the 'Avant-Propos dialogué' seems to pick up exactly where 'The contradictions of inheritance' stops. It asserts not only an influence of fields on wishes and desires, but stresses the very production of wishes by fields:Wishes are constituted as they are expressed. [When a field] offers possibilities of expression to wishes, it gives them raisons d'être, it legitimizes them and therefore creates them (…) If you change the space of possibles and legitimate expressions of wishes, you change wishes themselves (…). And isn't this a reproach that could be made to psychoanalysis, which often stops looking when the social begins to work on wishes, by providing them with opportunity to express themselves, but also principles of structuration and raison d'être (…).[Freud] did not have a sophisticated enough vision of the social world as a space of possiblesas a keyboard with which wishes can play and constitute themselves -to have a theory of the socialization of libido.(Maître and Bourdieu, 1994: XVI-XVII)

  criticism to embracing, refusal to acceptance, repression to transgression ? I have tried to show that even if such a repression-to-transgression interpretation has been suggested by Bourdieu himself, the fundamentals of his position spelled out in Le Métier de Sociologue remained the same. I, for one, do not regret this consistency. The 'scientific' and 'positivist' roots of French sociology may appear as rigid constraints and a heavy tradition, but those roots are what made French sociology what it is, in its specificity and also its contribution. It could be argued that the richness of sociology could indeed be lost in a 'socioanalysis' that would blur the specificity of the sociological eye because of a too close proximity with psychoanalysis -at the risk, highlighted by Bourdieu, of combining 'pop psychology' with soft sociology. This is why the epistemological stance outlined in some passages of 'The contradictions of the inheritance' and in some parts of the 'Avant-Propos dialogué' seems more desirable. A 'sociologisation' of psychoanalysis, which is what Bourdieu sought, consists in the acknowledgement of both the specificity and the sovereignty of sociology.

Acknowledgements

I want to thank Elizabeth Silva for having invited me to join, as a latecomer, the 'Psyche and habitus' project, and for her relentless help through different versions of this article. I am also particularly indebted to the editors and the anonymous reviewers of the article for their very detailed, challenging and generous comments.

This two-way street between wishes and institutions is finally defined by Bourdieu as the specific objet of a new discipline: 'socioanalysis'.

A socioanalysis which would truly go beyond the opposition between psychoanalysis and sociology should focus both on the way institutions work on wishes and on the way wishes work on institutions. (Maître and Bourdieu, 1994: XIX) 'Institutions or, better, fields…'

As far as this central theme of the dialogue is concerned, the discussion between Maître and Bourdieu (and implicitly between psychoanalysis and sociology) often uses correspondences. For example, they speak indifferently of 'social agents', 'individuals' or 'persons' (sujets), and of 'dispositions', 'instincts' or 'wishes', as if there were no distinction about the epistemological connotations of these terms. From the beginning, however, Bourdieu seems more cautious about one such correspondence, nevertheless often used in the text both by him and Maître: the one holding between the Bourdieusian notion of 'field' and the psychoanalytical use of the term 'institution'. At its first occurrence, Bourdieu speaks of 'the institution or, better, the field', and he elaborates on this more appropriate notion of field later in the discussion: 'One must not forget the elasticity of the institution; that's why I prefer to say ''field'', because there is always a space of possibles' (Maître and Bourdieu, 1994: X). Maître (one could argue that such an 'alternating' vision is that of Le Métier de Sociologue) v :

It is necessary to guard against thinking of these relationships as alternatives to each other. Sociology does not claim to substitute its mode of explanation for that of psychoanalysis. (Bourdieu, 1999: 512) But Bourdieu does not resort to dichotomous symmetry. He states that sociology is concerned '… to construct differently certain givens that psychoanalysis also takes as its objects, and to do so by focusing on aspects of reality that psychoanalysis pushes aside as secondary or insignificant'. The specificity of sociology is also to take very seriously and to study for themselves realities that psychoanalysis 'treats as defenses that have to be breached to get to the essential element (for example, academic or professional disappointments, job conflicts, etc.).' (Bourdieu, 1999: 512). Moreover, Bourdieu does not call here for a unification of the explanations of sociology and psychoanalysis and he seems rather skeptical about the possibility of escaping 'eclectic rapprochements of pop psychoanalysis and soft sociology' when trying to built a 'socioanalysis' (Bourdieu, 1999: 512).

Here, rather than alternative, symmetrical or united disciplines, sociology and psychoanalysis appear as complementary ways of looking at -sometimes the same -things. And Bourdieu's point of view is clearly sociological. In his Notes 1 Paraphrasing Lucretius and his theory of atoms, Bourdieu used this expression ('les atomes crochus de l'habitus') to talk about the not so mysterious and socially constructed affinities between habituses.

2 Indexes were closely monitored by Bourdieu, and they can be used as indications of what he actually wanted to signal as important in his books.

3 All excerpts from the Avant-Propos dialogué are translated by me. To translate technical psychoanalytical terms, I used the Freudian glossary provided by http://www.psychanalyse.lu/articles/Glossaire.htm, consulted in April 2013. 4 Jean-François Fourny (2000: 104, 107) already depicts such 'oscillation' and 'hesitations' in Bourdieu's relation to psychoanalysis, but refers Bourdieu's 'ambiguity' to a 'potentially destabilizing conflict' and an 'uneasy relationship with psychoanalysis'. George Steinmetz describes also vividly these moments when Bourdieu 'takes back with one hand what he has given with the other', but likewise tends to describe them in psychological or even pathological terms, for example as a 'characteristic defensive move ' (2006: 447), as a 'disavowal' which has an 'obsessive quality ' (2006: 452), as an 'allergic relationship' (to Lacan) (2006: 459), as an 'affliction'(2013 : 128), a 'problem', a 'failure' or an 'error', 'because so many of Bourdieu's ideas are based on, or require integration with, psychoanalysis (especially the Lacanian version) ' (2006: 448). By using the phrase 'pas-de-deux' I would like on the contrary to offer a more neutral