Gaël Plumecocq
email: gael.plumecocq@toulouse.inra.fr

The second generation of ecological economics: How far has the apple fallen from the tree?

Keywords: Discourse analysis, Ecological economics, Environmental economics, Editorial choices, Textual data processing

The paper analyzes 6,237 abstracts of articles published in four journals since 1989. -I have examined how scientific discourse produced in Ecological Economics has evolved.

-Ecological economics discourse is converging toward environmental economics.

-The valuation of ecosystem services discourse has become central in ecological economics.

-The prevalence of pragmatism in the field and in the editorial boards explains this trend.

Introduction

In recent years, articles have been published envisaging the future of ecological economics [START_REF] Spash | Social ecological economics: Understanding the past to see the future[END_REF][START_REF] Anderson | Does ecological economics have a future? Contradiction and reinvention in the age of climate change[END_REF][START_REF] Spash | New foundations for ecological economics[END_REF]. These articles have echoed and increased the large number of publications analyzing ecological economics. In this line of research, we can distinguish historical analysis and reports from personal experience [START_REF] Spash | The development of environmental thinking in economics[END_REF][START_REF] Pearce | An intellectual history of environmental economics[END_REF][START_REF] Costanza | The early history of ecological economics and the International Society for Ecological Economics (ISEE)[END_REF][START_REF] Røpke | The early history of modern ecological economics[END_REF][START_REF] Røpke | Trends in the development of ecological economics from the late 1980s to the early 2000s[END_REF][START_REF] Spash | The state of ecological economics: A decade of European experience[END_REF] and from more normative works defining the goal of ecological economics [START_REF] Costanza | What is ecological economics?[END_REF][START_REF] Norgaard | The case for methodological pluralism[END_REF][START_REF] Van Den Bergh | Ecological economics: themes approaches, and differences with environmental economics[END_REF][START_REF] Özkaynak | Whither ecological economics?[END_REF]Gowdy and Erickson, 2005a;[START_REF] Spash | New foundations for ecological economics[END_REF]Martinez-Alier, (forthcoming)). Although both kinds of research aim at finding common ground for the community of researchers, they also employ discourse on the reasons why we should adopt an ecological economics approach towards environmental problems [START_REF] Luks | The rhetorics of ecological economics[END_REF]. As a result, from individual researchers' perspectives, they define what 'good' ecological economists should be.

The purpose of this paper is to analyze this discourse produced by ecological economics since the emergence of the field in 1989, and examine the relationship between the second generation of ecological economics and the origins of the movement. Evidence of these discourses can be found in academic journals of the ecological economics community, and in particular, Ecological Economics (EE hereafter). Of course, the discourse of ecological economics is not exhaustively summarized in the articles published in EE, and the authors published in the journal are often distantly related to the community if at all. Yet, EE articles can be used as representative of the discourse prevailing in the field because EE has institutional rules and organizational structures ensuring that the articles published, in addition to meeting academic standards, are also consistent with the paradigms prevailing in the field. To a certain extent, the principles and procedures of decision-making for publication in EE complies with the normative requisites prevailing in the field. For instance, when selecting new members for the editorial board in 2009, the Editor-in-Chief wrote, "These individuals were selected to provide service opportunities to new members of the ecological economics community, taking into account the journal's evolving intellectual focus and the increasingly international scope of our field. Selections were made by the Editor-in-Chief in close consultation with the publisher and the leaders of the International Society for Ecological Economics" (Howarth, 2009, p. 593).

Analyzing scientific discourse requires considering that the production of knowledge is about defining narratives. The second section of this paper investigates the ways in which articles published in academic journals can be considered as discourses and analyzed as such. The third section then questions the discourses produced in ecological economics through textual analysis of abstracts by (i) comparing the evolution of environmental and ecological economics discourses and (ii) studying the evolution of the semantic content of the EE publications. Abstracts of articles published in EE, in the Journal of Environmental Economics and Management (JEEM), in Environmental Values (EV), and in Environmental and Resource Economics (ERE) between 1989 and 2013 have been processed with innovative methods of textual data analysis, namely Alceste [START_REF] Reinert | Une méthode de classification descendante hiérarchique : application à l'analyse lexicale par contexte[END_REF][START_REF] Reinert | ALCESTE : Une méthodologie d'analyse des données textuelles et une application : Aurélia de Gérard de Nerval[END_REF] and Iramuteq [START_REF] Ratinaud | IRaMuTeQ : implémentation de la méthode ALCESTE d'analyse de texte dans un logiciel libre[END_REF] software. Results presented in the fourth section suggest that ecological economics discourse is evolving towards convergence with environmental economics discourse. Following [START_REF] Illge | A matter of opinion-How ecological and neoclassical environmental economists and think about sustainability and economics[END_REF], there are some common points between ecological and environmental economics (Gowdy and Erickson, 2005b;[START_REF] Spash | Economic schools of thought on the environment: investigating unity and division[END_REF]. Results in this study particularly point to the increasing importance of the evaluation of ecosystem services in ecological economics discourse. Finally, I discuss this trend and interpret it as the prevalence of an academic convention supported by (i) the ambition to improve EE's success and (ii) the justification of a pragmatist paradigm (Section 6). I conclude by questioning the kind of transdisciplinarity promoted by ecological economics.

Talking about Discourse in Ecological Economics

Post-modern science not only follows from the need to address complex issues in a fast-changing world, it also acknowledges the fact that research must address urgent societal issues (Funtowicz andRavetz, 1991, 1994). The aim of this section is to clarify the ways in which research can be considered as a collective discourse. Such clarification leads to considering the power issues that arise in the production of discourse.

Post-normality, Norms, and Constructivism

Ecological economics was first created as a forum providing space for criticizing 'normal science,' i.e. science based on an oversimplification of complex issues and aiming at predictions. It also sought to propose an ambitious scientific project by re-embedding science into society, challenging technological paradigms, and seriously considering the issue of the size of the economic scale [START_REF] Costanza | Toward an ecological economics[END_REF]. This ambition required a paradigm shift, that is, a revolution in the way knowledge is constructed [START_REF] Kuhn | The structure of scientific revolution[END_REF]. In this sense, the scientific revolution described by Kuhn is a process through which the norms of producing scientific theories or knowledge are questioned and replaced by other norms. For instance, ecological economics considers that knowledge is useful as long as it produces operational solutions, while traditional, positivist science judges the usefulness of knowledge in regard to the accuracy of its predictions [START_REF] Friedman | The methodology of positive economics[END_REF].

If we accept the premise that theories are a way to simplify complex realities, then we have to acknowledge that the acceptability of theories or knowledge claims depends on: (i) the ways in which they are communicated within and/or outside the scientific sphere [START_REF] Luks | The rhetorics of ecological economics[END_REF] and (ii) the pre-analytical choices and problem-structuring of a given issue [START_REF] Özkaynak | Whither ecological economics?[END_REF][START_REF] Giampietro | Multi-scale integrated analysis of agroecosystems[END_REF]. To address these two aspects, we must ask a decisive question regarding ontology, i.e. the status that researchers grant to reality. Reality can be either perceived as a something that exists (realism) or something that is constructed (constructivism) -or any blending of these extremes. Answers may vary across disciplines, the subjects under study, or even by researchers. 1 Constructivists either emphasize the equipment the scientific production process requires [START_REF] Latour | Laboratory life: the social construction of scientific facts[END_REF], the historical determinants of science [START_REF] Hacking | Historical ontology[END_REF], or the social effects induced by knowledge production [START_REF] Hacking | The social construction of what?[END_REF][START_REF] Daston | Objectivity. Zone Books[END_REF]. For constructivists, the structuring of the problem, e.g. establishing categories for analysis, means formatting reality. Moreover, since complexity implies non-equivalent perspectives, choices of narratives have to be made [START_REF] Allen | Narratives and transdisciplines for a post-industrial world[END_REF]. Therefore, theories only tackle a limited set of facets of 'reality.' Yet moving beyond the split between realism and constructivism, the ways in which science is communicated is also a matter of importance, not only because of the conception of reality it reflects or because of the socio-political effects it induces, but because controlling perceptions about rightness is an issue of power (Martinez-Alier, 2001).

What is Academic Discourse (also) About?

Identifying who (e.g. which peer community) has the ability to design such norms and to which extent they have the power to impose them is therefore crucial because these norms influence the magnitude of theories' acceptance. Indeed, according to Kuhn, the willingness to accept a new scientific theory is not only a question of formal logic. It also depends, maybe to an even greater extent, on its emotional effects and resonance within peer communities (Kuhn, 1957, p.40). In this sense, paradigms not only refer to sets of concepts, theories, and accepted practices within a field of inquiry, but also encompass the entire worldview that this set entails [START_REF] Kuhn | The structure of scientific revolution[END_REF]. It follows, then, that arguing about truth entails arguing about much wider representations of the world. Hence, scientific discourses are not only about producing valid knowledge, but also about power relationships. In other words, discourses not only reflect power relationships or are conceived as a way to make a statement be accepted as truthful, but are also a means to control commonly accepted representations on how the world functions. In this sense, academic discourse, and in particular ecological economics discourse, is rhetoric [START_REF] Luks | The rhetorics of ecological economics[END_REF][START_REF] Shi | Ecological economics as a policy science: Rhetoric or commitment towards an improved decision-making process on sustainability[END_REF].

In ecological economics, some studies have already highlighted questions of power and influence within the field [START_REF] Røpke | Trends in the development of ecological economics from the late 1980s to the early 2000s[END_REF][START_REF] Spash | Social ecological economics: Understanding the past to see the future[END_REF]. For instance, [START_REF] Røpke | Trends in the development of ecological economics from the late 1980s to the early 2000s[END_REF] documented the following event at the 1996 conference of ecological economics at Versailles St. Quentin University: during the conference, David Pearce (who at the time was associate editor of the journal Ecological Economics) claimed that ecological economics was a sub-discipline of environmental economics. The result was that he had to leave his position on the board of the journal [START_REF] Spash | Social ecological economics: Understanding the past to see the future[END_REF], also refers to this event, but noted that "Pearce was not separated from the journal for another two years", p.353). The same sort of censure arose when Cutler Cleveland took over as editor of the journal in 2002. Clive Spash, who had been appointed board member few months before, was dismissed along with others [START_REF] Røpke | Trends in the development of ecological economics from the late 1980s to the early 2000s[END_REF]. In some cases, it remains difficult to sort out the reasons why some people were excluded from the field of ecological economics. What we can say with certainty is that not every discourse is (or has been) admissible within ecological economics.

Sources of Scientific Discourse

As these two examples highlight, academic discourses are found primarily in conferences and in academic journals. Such a distinction refers to what [START_REF] Luks | Post-normal science and the rhetoric of inquiry: Deconstructing normal science?[END_REF] called internal and external rhetoric: internal rhetoric aims at persuading a specific audience (within a scientific community) while external rhetoric aims at convincing a more universal audience (science as a whole, or even the whole world) (Perelman, 1977 introduced this distinction between "persuasion" and "conviction" in the line with the tradition established by Kant and Pascal). 2 The present study is concerned exclusively with the external discourse of ecological economics for two reasons: (technical and practical reasons are discussed in the next section):

-First, articles present arguments in the most scientific way. They respond to certain codes and norms of presentation [START_REF] Collins | The structure of knowledge[END_REF], while debates in conferences are often more open and may drift to discussing normativity and even the ways science is/should be done. In this study, the purpose is to highlight the differences between fields of scientific production over time, starting with the most 'neutral' method of expression. Journal articles, therefore, enable us to control for the biases of style to some extent. -Second, the production of articles is much more institutionalized than the debates occurring during conferences. Journals are equipped with a set of rules validating knowledge claims (e.g. articles are examined through the peer-review process). Moreover, there are rules and norms that authors must comply with: the journal's aims and scopes define the admissible topics and the research positioning to be adopted, citing the journal's previous publications is encouraged, final decisions on publication are made by editorial boards, etc. These rules are not only about assessing the truthfulness of papers, but also judging whether or not they comply with the discourse the journal wants to produce. In this regard, they are institutions aiming at controlling discourse.

An interesting feature of the journal Ecological Economics (EE) is that its institutional organization has experienced very few changes since its creation. It is worth noting that the aims and scope of the journal have remained almost unchanged since 1989. 3 In the same vein, very few changes have occurred among its editors: Costanza was Editor-in-Chief from 1989 to 2002, Cleveland from 2002 to 2007, and Howarth from 2007 to the present. Moreover, the associate editors have remained almost the same through each handover (they remained exactly the same when Howarth took over).

The only change of importance that can be noted in the editorial organization of the journal was in 2009, when 19 members were reappointed to the board [START_REF] Howarth | Welcoming new board members[END_REF]. 4 At that time, Stefan Baumgärtner and Sharachandra Lélé replaced Mike Young as Associate Editors (the latter remained in the Editorial Advisory Board of the journal). Finally, another important feature concerns the reviewing process, which is single-blind. In this case, reviewers have access to the identity of the authors. Sometimes, in particular in the early days of the journal, reviewers could choose to reveal their identity, either by signing their reviews or upon the author's request. No clear justification emerges for this choice (Howarth and Spash, personal communication).

Research and Methods

Discourse analysis is a useful method for investigating scientific knowledge claims, not only through utterances, that is, the meaning of what is actually written or said [START_REF] Habermas | On the pragmatics of communication[END_REF], but also concerning the socio-institutional context in which those utterances were made [START_REF] Harris | L'analyse du discours[END_REF]. It enables us to compress the information contained in large numbers of texts and also to situate utterances in regard to the broader context of knowledge production. This section (i) presents the samples used to bring to light EE discourses as well as the encoding variables chosen to tackle the institutional context of discourse production; and (ii) exposes the method used for analyzing the ways in which this discourse has evolved. This method is interdisciplinary by nature and involves blending hermeneutics with the genealogy of discourse production. Textual data treatment facilitated this process, while ensuring the replicability of results.

3.1.

Data Collection and Sampling The first hypothesis was that the distance between environmental and ecological economics was decreasing and that disciplinary barriers were tending to fade (Gowdy and Erickson, 2005b;[START_REF] Illge | A matter of opinion-How ecological and neoclassical environmental economists and think about sustainability and economics[END_REF][START_REF] Spash | Economic schools of thought on the environment: investigating unity and division[END_REF]. A study by [START_REF] Spash | Economic schools of thought on the environment: investigating unity and division[END_REF] suggests that EE has now become a reference shared by both ecological and environmental economists. Yet, how has the discourse in EE developed in relation to the one prevailing in the environmental economist community? The journals selected for this study cover both communities. In addition to EE, the Journal of Environmental Economics and Management (JEEM) has been identified as the most authoritative outlet for the environmental economist community [START_REF] Spash | Economic schools of thought on the environment: investigating unity and division[END_REF]. There have been many studies comparing the two journals [START_REF] Ma | Environmental and ecological economics: a citation analysis[END_REF][START_REF] Hoepner | Environmental and ecological economics in the 21st century: An age adjusted citation analysis of the influential articles, journals, authors and institutions[END_REF][START_REF] Spash | Economic schools of thought on the environment: investigating unity and division[END_REF]Spash, 2013a).

EE and JEEM are comparable in terms of impact factor. 5 From the standpoint of discourse production, this means that the discourses produced have similar academic prestige. Nevertheless, there are some significant differences in the number of articles published each year, in particular since the number of issues published per year by EE increased in 2006 (see Figure 1). These differences may cause biases in the discourse analysis. Discourse from EE and JEEM has been complemented with peripheral journals: Environmental Values (EV) for the former and Environmental and Resources Economics (ERE) for the latter, as suggested in [START_REF] Spash | Economic schools of thought on the environment: investigating unity and division[END_REF]. To some extent, adding journals to the core journals of the two communities also enables us to distinguish between the discourse produced by ecological economics as a community and the discourse produced within the journal EE (Spash, 2013a).

Abstracts were collected through the Thomson Reuters Web of Knowledge® database for all the years available (1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013). Before 1994 and for the last issues published but not yet referenced in the database, or when the journal was missing from the Web of Knowledge® database, abstracts were collected via the concerned journal's website. The time frame was set from 1989 when the journal EE was created up to December 2013. Recurring errors have been detected in the abstracts of ERE between 2000 and 2004 (4 to 8 spaces were missing in some of the words in the abstracts). These errors have been manually corrected.

Abstracts were then compiled into a single textual corpus (see Appendix A). Variables have been added in order to identify the year of the journal's publication (variable PY, subvariables are the years from 1989 to 2013) and the name of the publication (variable SO, categories EE, JEEM, EV, and ERE). 6,237 abstracts were analyzed. Over the entire period, 58% of the abstracts were from ecological economics and 41% from environmental economics. Figure 1 displays the number of abstracts analyzed for each journal between 1989 and 2013.

3.2.

Methods and Results Analyzing discourse produced while accounting for its complexity requires using multiple methods [START_REF] Norgaard | The case for methodological pluralism[END_REF]Costanza et al., 1997a). Of course, these methods need to share the same basic ontologies [START_REF] Ahmed | When multi-method research subverts methodological pluralism-or, Why we still need single-method research[END_REF][START_REF] Spash | New foundations for ecological economics[END_REF]. Here, I combine a hermeneutic of statistical treatment of texts with an historical approach to discourse production. These methods used in this way are consistent with the constructivist perspective of science endorsed in Section 2. Indeed, scientific discourses are not produced in a vacuum. On the one hand, they take place in a context of editorial choices and are influenced by prevailing social conventions of what valuable knowledge production is for a journal (e.g. knowledge that will increase the Impact Factor of a given journal). On the other hand, academic discourse evolves over time, which means that valuable knowledge is also influenced by socio-historical factors and contingent societal concerns (e.g. climate change, ecosystem services).

Analyzing textual content to such an extent may be difficult, or at least require a large amount of resources (for instance, see [START_REF] Luzadis | The science of ecological economics: a content analysis of ecological economics, 1989-2004[END_REF], for a laborious content analysis of a survey of 200 articles published in EE). The method of textual statistics used here compresses the information contained in large texts in such a way that it can be more easily interpreted [START_REF] Reinert | Une méthode de classification descendante hiérarchique : application à l'analyse lexicale par contexte[END_REF][START_REF] Benzécri | Correspondence analysis handbook[END_REF][START_REF] Lebart | Statistique textuelle[END_REF]. I then used (i) correspondence analysis [START_REF] Benzécri | Correspondence analysis handbook[END_REF], and (ii) a descendant classification [START_REF] Reinert | Une méthode de classification descendante hiérarchique : application à l'analyse lexicale par contexte[END_REF] to obtain visual representations that put the main information to be analyzed into a form. More fundamentally, these two methods allow results to be replicable, which is definitely a problem in qualitative studies [START_REF] Dafoe | Science deserves better: the imperative to share complete replication files[END_REF][START_REF] Ishiyama | Replication, research transparency, and journal publications: individualism, community models, and the future of replication studies[END_REF]. Data processing was facilitated by the use of two tools: Alceste software has been developed along the lines of Max Reinert's research, which initiated the method of descendant classification [START_REF] Reinert | Une méthode de classification descendante hiérarchique : application à l'analyse lexicale par contexte[END_REF][START_REF] Reinert | ALCESTE : Une méthodologie d'analyse des données textuelles et une application : Aurélia de Gérard de Nerval[END_REF]; and Iramuteq, which has recently been developed on a R basis, reproducing the original Alceste algorithm and displaying complementary statistical information [START_REF] Ratinaud | IRaMuTeQ : implémentation de la méthode ALCESTE d'analyse de texte dans un logiciel libre[END_REF]. 6 These two methods (correspondence analysis and hierarchical classification) proceed from conventional statistics applied to the root-words used in texts and in particular to multivariate data processing. Forms of words (such as infinitive forms of verbs or the singular for common names) are characterized as an interrupted chain of signs (i.e. letters, or numbers, but not punctuation) in order to be automatically processed. 7 A supplementary variable has been introduced to distinguish ecological from environmental economics discourse (variable name is Type, and subvariables are Ecol for ecological economics discourse and Env for environmental economics discourse). From this set of variables, two have been created to account for both the arena of discourse production (i.e. the type of journal) and the year of production: the DistType variable refers to the text published by a type of journal at some point in time (subvariables are Ecol1989, Ecol1990, Ecol19991… to Econ2012, and Econ2013, in all, 50 subvariables). The Dist variable refers to the text published in a journal at a given point of time (modalities are EE1989, EE1990…, EV1992, EV1993… ERE1991, ERE1992, to JEEM2012, and JEEM2013, 95 subvariables in all).

Correspondence analysis and hierarchical classification together enable us to link discourses (statistically understood as a group of forms of words) to variables.

Evolution of EE Discourse

The results obtained by correspondence analysis and hierarchical classification are presented in the two following sub-sections. They suggest that (i) ecological and environmental economics have tended to move closer over time and that (ii) ecosystem services valuation methods and debates are increasing over time.

4.1.

How have the Ecological and the Environmental Economics Discourses Coevolved? Correspondence analysis has been used to analyze the entire corpus in regards to the two variables DistType (the evolution of the distance between communities -Figure 2a.) and Dist (the evolution of the distance between journals -Figure 2b.). The aim was to see how the ecological and environmental economics discourses have coevolved since 1989 and how the core journals (EE and JEEM) compared with peripheral journals (EV and ERE) in these trends.

Correspondence analysis proceeds from a matrix where forms of words are placed in rows and variables are placed in columns. Proportions of occurrences of forms in relation to a given subvariable are then evaluated through a chi-square test. The variability of the data assessed as a chi-square value is then statistically explained by inertia. The correspondence analysis graph then displays the distance between the subvariables of a given variable according to the vocabulary that is significantly associated with each subvariable. Figures 2a and2b display the representations for factor 1 (27.01% of the inertia) and 2 (22.60% of the inertia) of the variability in the DistType (the evolution of the distance between communities) and the Dist (the evolution of the distance between journals) variables (respectively). Here, the meaning of the factor provided by the variability of the forms of words making up discourses is not fundamentally relevant. Indeed as the information contained in the 6,308 abstracts is substantially compressed (half of the inertia is explained by two factors), the meaning of the factors is necessarily imprecise (Appendix C displays the distribution of the vocabulary according to the two main axes, which enables us to interpret the factors explaining the variability of discourse and variables: from theoretical-conceptual to methodological concerns for factor 1; from the description of empirical domains to scientific vocabulary for factor 2). The aim is rather to characterize the coevolution of the two fields of ecological and environmental economics and deconstruct this coevolution according to the core journals of these fields.

Figure 2a suggests that (i) environmental economics is evolving from year to year, from assessing preferences through willingness to pay to analyzing market devices for environmental management, in particular in the agricultural sector; (ii) ecological economics is evolving from a very specific position (defining and circumscribing the field of ecological economics) to biodiversity assessment and management; and (iii) that ecological economics is drifting toward environmental economics, while the opposite does not seem to be the case. Figure 2b suggests that (i) environmental economists have a much more unified discourse than ecological economists, (ii) EE explains most of the variability of the evolution in the ecological discourse, and (iii) in the most recent period, EE is relatively close to the environmental economics discourse.

How has Ecological Economics ' Discourse Evolved?

The aim of the descendent classification was to analyze the evolution of the discourse produced in the journal. For this purpose, analyses were conducted on the sub-corpus of the 3,162 EE abstracts only. Abstracts and forms (lemmatized forms of words) were placed in a matrix counting the number of times a form (placed in a row) appeared in an abstract (in columns). The proportions of occurrences of forms in abstracts were then calculated. An algorithm of computation [START_REF] Ratinaud | Application de la méthode ALCESTE à de "gros" corpus et stabilité des "mondes lexicaux"?: analyse du[END_REF] was then applied to the matrix to obtain a grouping of abstracts that were highly contrasted in terms of the repartition of forms (i.e., two groups of abstracts with very few overlapping forms are obtained). A chi-square test was then calculated for every possible subdivision of these groupings. The most significant classification of forms contained in the grouping of abstracts was retained. The chi-square value was calculated on forms, variables, and abstracts. The significance threshold of the chi-square test was set at 3.84, which means that there is a 0.05% chance that a correspondence between forms, variables, or abstracts and a class of words contained in the abstracts is random.

Descendant classifications have been constructed to define a supplementary variable (P was set as a period variable, grouping several years of publication): instead of an abstract, columns exhibited subvariables of the variable (first period, second period) and emphasized the most significant vocabulary for every period. The definition of periods followed a trial and error process. Several classifications were constructed with different groupings of years that were similar in terms of the number of abstracts published. Finally, the most meaningful classification was retained for 7 periods (i.e. 7 subvariables for the variable P). Figure 3 displays the final classification used.

In the classification, a given form is not meaningful in itself, but should be analyzed in terms of the semantic context (i.e. the class of forms) in which it has been used. The other forms of the class can provide indications about the ways in which a given form has been used. Theoretically, if a single form is used in two different contexts, it should appear in two separate classes. This should solve the problem of positive or negative use of a form (e.g. monetary valuation being used as a tool for revealing preferences or being criticized as a concept). Given the level of compression of information (because of the amount of text analyzed), I suspected this condition was not fulfilled, and then collected the most significant abstracts of each period. Representative references (in chisquare terms) are summarized in Table 2 to provide a clearer direction on the use of the terms (for example, when the form wtp was significantly used in a given period, was it used for the same purpose as in other periods?).

Table 1 -Descendent Classification: Evolution of the Ecological Economics Discourse 1989-2013

Note. This descendent classification provides the most representative vocabulary (list of forms) associated to each period for the EE corpus between 1989 and 2013. The chi-squared value assesses the significance of the association between a form (lemmatized words) and the vocabulary used in a given period (chi-squared value 3.84 corresponds to a 0.05% chance of random association). Usually, significance is linked to the presence of the vocabulary in a given period, but rarely a form often associated with a given vocabulary may be associated to the period it is less frequently used in, despite appearing more often in the rest of the abstracts. To account for this phenomenon, the percentage of a form's presence in a given period is provided. For instance, the most representative form in the first period is econom (lemmatized form of economic). 22% of the occurrences of this form appear in the first period. Forms in bold refer to issues valuation and ecosystem services.

The vocabulary used to construct each period and the significant abstracts for each period enable us to interpret EE's contribution to ecological economics discourse over time:

-The first period (1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999): EE contributed to conceptualizing the field of ecological economics (concept, sustainability). 8 This discourse formed the basis of the intellectual influences of the movement. Concepts borrowed from thermodynamics, such as entropy, are the most significantly associated to this period, which is also marked by references to neoclassical economics, to differentiate from it but also to contribute to it (Table 2). -In the second period (2000)(2001)(2002), studies published in EE are most significantly empirical. Here, the goal was not conceptualizing, but applying concepts such as sustainability. In this period, ecological disciplinary views seem to prevail (Table 2), and the need for assessment (valuation) of the role of the ecosystem and in certain areas, environmental regulation, was brought to the fore (km, ha). -In the third period (2003)(2004)(2005), EE's discourse focused on biodiversity issues as representative of the under-representation of the ecosystem in decision-making processes, and in particular in the agricultural sector. It is important to note that economic vocabulary is not significantly associated to the discourse prevailing in this period. -The fourth period (2006)(2007) is oriented towards deciding on methodologies to account for the hidden processes of ecosystems, and in particular to providing scientific measures of natural phenomenon. In this period, no unquestioned criterion on which to base evaluation is imposed, but valuation increases as a conventional tool for management. -In the fifth period (2008)(2009), economic valuation, in particular through wtp, is used jointly with biophysical indicators such as ecological footprint (ef) and net primary product (npp). The most significant issues of the period are water (hydrology, river) and energy (biomass, fossil). -In the sixth period (2010)(2011), market instruments of regulation, such as pes, are analyzed (also from a justice perspective), as well as constructed (Table 2). Preferences are not only assessed through wtp (as was the case primarily in the previous period), but also revealed in actual payment. It is important to note that EE not only analyzed such processes, but also contributed to imposing them [START_REF] Söderbaum | Ecological economics in relation to democracy, ideology and politics[END_REF]. This trend relied on and contributed to the notion of ecosystem_services.

-The seventh period (2012)(2013) is marked by ecological economics concepts (resilience) and very general issues (climate). Though the trend is less obvious than in the previous period, the notion of ecosystem_services is still very present.

Moreover, Table 2 suggests that the significance of the vocabulary displayed in Table 1 may be underestimated. Indeed, the most representative references of the discourse production in the last two periods (since 2011) all discuss and/or apply valuation techniques. Most of them use money as the valuation metric. Note. Table 2 displays the most representative abstracts of each period defined in Table 1. A chi-square test was calculated on the proportion of words contained in the abstracts vs. the proportion of words contained in other abstracts of other periods. The significance threshold was set to a chi-square value of 3.84, for which there is a 0.05% chance that the association between a given abstract and a given period is random.

5. Discussion: How Pragmatism Shapes the Language of Ecological Economics Results drawn from textual analysis seem to indicate (i) a tendency of EE to move closer to the discourse produced in the field of environmental economics (Figures 2), and (ii) the co-emergence of the notion of ecosystem services on the one hand, and the resort to monetary valuation techniques on the other hand (Tables 1 and2). In this section, I present the hypothesis that the adoption of a pragmatic position within the community is causing the double trend described in Section 4.

The Creation of a Favorable Context

Three elements provide a favorable context for this trend to occur: the mechanisms for attracting mainstream economists within the community; the editorial policy of the journal EE; and a shift in the stance of the most influential ecological economist, Robert Costanza.

The first clue lies in the coexistence, within ecological economics, between mainstream economists and heterodox economists. [START_REF] Røpke | The early history of modern ecological economics[END_REF][START_REF] Røpke | Trends in the development of ecological economics from the late 1980s to the early 2000s[END_REF] even emphasizes that in the early 90s, the mainstreaming of ecological economics was a conscious strategy. The latter developed innovative methods, theories and scientific practices in order to develop inventive solutions, while the former had the power to impose a particular political agenda. The results highlighted in the textual analysis in Section 4 reflect this phenomenon. On the one hand, we can see a growing plurality in the concepts, methods (including valuation methods), issue-areas, and so forth appearing in EE discourse (in Table 1, words appearing in one period are often not present in the previous or following periods). On the other hand, the barriers between ecological and environmental economics -at least for some dimensions -seems to become blurred (see Figures 2).

To some extent, the editorial policy of the journal is permeated with this strategy. First, increasing the number of articles published each year (see Figure 1) promoted a diversity of narratives and languages within EE, but also opened the journal more broadly to environmental economists. Røpke (2005, p.271) thus noted that mainstream economists "became increasingly visible in the journal, especially when the number of issues was increased from 1994." Second, by seeking (and succeeding) to increase the academic prestige of the journal, editorial policy opened a wide and attractive space for scholars interested in combining environmental and socio-economic concerns, and for multiple viewpoints and perspectives that have enriched the field over the years. In the 'publish or perish' academic context, publishing in EE appears all the more desirable for an increasing number of scholars. In 2008, roughly 700 papers were submitted (Howarth personal communication), whereas in 2013, more than 1100 papers were submitted to EE (calculated from the acceptance rate published by the Elsevier Website). While the proportion between mainstream and heterodox economists may have remained unchanged compared to the early days of the journal, in absolute terms, mainstream vocabulary appears more significant in the textual analysis (irrespective of how this vocabulary may have evolved over time).

The final clue can be seen in the career-path of Robert Costanza, the leading and founding member of the International Society for Ecological Economics and of the journal Ecological Economics (he was also its first Editor-in-Chief until 2002) and probably the most influential author in the EE field and the journal. He was trained as an Aerospace Engineer (1968)(1969)(1970), received a BA in Architecture (1973), an MA in Architecture/Urban and Regional Planning (1973), and finally a Ph.D. in Systems Ecology, Environmental Engineering Sciences with a minor in Economics (1979). 9 His supervisor was Howard T. Odum, a complex system ecologist who applied entropy flow to account for the energy appropriation of systems (e.g. [START_REF] Odum | Environmental accounting: Emergy and environmental decision making[END_REF]). Costanza's early works [START_REF] Costanza | Embodied energy and economic valuation[END_REF] were in line with energy analysis, but slowly evolved to ecosystem services monetary valuation (Costanza et al., 1997b may be seen as a significant turning point). The congruence of these two trajectories indicates the influence Costanza had [START_REF] Røpke | Trends in the development of ecological economics from the late 1980s to the early 2000s[END_REF][START_REF] Spash | Social ecological economics: Understanding the past to see the future[END_REF] and still seems to have over the editorial choices of EE, and more broadly, on the field.

The Risks of Pragmatism

Costanza's career path can then be used to approach the trends observed in EE (e.g. [START_REF] Anderson | Does ecological economics have a future? Contradiction and reinvention in the age of climate change[END_REF] refer to Costanza's positions in regards to Stern's report on climate change to establish a hypothesis on broader approaches used in the field of ecological economics). Deconstructing the mechanisms by which a system of influence remains in scientific production would take us beyond the scope of this paper -although such a study would be of major interest. Rather, this paper focuses on the justifications behind such choices, which have since been constructed as a social convention among many ecological economists and beyond. The reason for this turn in research, Costanza explained, was to shape a language that would influence political decisions quickly and in a decisive way. Similarly, the notion of ecosystem services was coined as a metaphor to appeal to public opinion [START_REF] Norgaard | Ecosystem services: From eye-opening metaphor to complexity blinder[END_REF]. [START_REF] Spash | The New Environmental Pragmatists, pluralism and sustainability[END_REF][START_REF] Spash | Social ecological economics: Understanding the past to see the future[END_REF][START_REF] Spash | New foundations for ecological economics[END_REF]Spash ( , 2013b) ) termed this approach 'New Environmental Pragmatism': "the most important role for research is to be pragmatic and employ whatever approaches are effective to inform the policy community about environmental problems and their solution" (Spash andRyan, 2012, p.1101, authors' emphasis). Although there is a lack of consensus on this approach at the community level [START_REF] Douai | Economie écologique et économie hétérodoxe : pour une socioéconomie politique de l'environnement et du développement durable[END_REF][START_REF] Spash | Economic schools of thought on the environment: investigating unity and division[END_REF], increasing references to ecosystem services through a monetary valuation perspective can be interpreted as a sign that New Environmental Pragmatism is growing within ecological economics. This idea is further supported by Costanza's justifications of his research orientations, as well as his judgments on the use of neoclassical economics methodologies. [START_REF] Anderson | Does ecological economics have a future? Contradiction and reinvention in the age of climate change[END_REF] thus noted that "Costanza's review of Stern's strategy [of the carbon trade price market] points to a contradiction at the core of ecological economics, a contradiction between mainstream means and heterodox ends, with a confused space in between" (p.39). This "contradictory and confused space" is probably the price of combining pragmatism and pluralism.

It would be useful to assess the extent to which ecological economists contributed to this context of academic pragmatism beyond the scope of ecological economics itself, and how it contributes to blurring the frontier between mainstream orthodox economists and heterodox economists. Here, I merely point out the fact that there is common ground between environmental and ecological economics, persisting over time in EE, which I interpret as influenced by the increase of the pragmatist approach. This common ground expresses itself by the use (and maybe the co-construction) of a common language. The results presented here seem to suggest that opening up to the language of monetary valuation and ecosystem services serves the pragmatic purposes of academics by weighing on decision-making (Norgaard, 2010, Barnaud and[START_REF] Barnaud | Deconstructing ecosystem services: uncertainties and controversies around a socially constructed concept[END_REF]. However, "the language of the New Environmental Pragmatists is one of the market place, accountants, financiers and bankers" (Spash, 2009, p.256). This may be problematic since the increasing use of a given language outlines the beliefs and representations of a community. Journals are a fundamental tool for shaping this language, as Anderson and M'Gonigle (2012) suggest in the case of climate change. Moreover, the choice of a particular type of valuation can be interpreted as a way to impose a particular representation of the world (Martinez-Alier, 2003). Of course, I am not suggesting that this "implicit acceptance of the hegemony of mainstream economic methodologies," as addressed by Anderson and M'Gonigle in their abstract (2012, my emphasis) is voluntarily shaping language to exclude other ways of framing problems and envisioning solutions. The convergence described in Section 4 may not appear as a convergence of a shared or overlapping problem domain, nor as a tacit agreement on monetary techniques. It can also be viewed as the result of a kind of language imposing itself as a convention enabling communication, debates and even critiques to take place among communities and within ecological economists, but on a register that is far from being neutral.

Conclusions: Where do We Go from Here?

This paper retraces the evolution of EE's publications and concludes that it has drifted toward environmental economics and an increasing use of ecosystem services valuation as a way to influence political decisions. I have suggested that this 'pragmatic' position is largely shared by environmental researchers at large, which is contributing to establishing ecosystem monetary valuation as a social convention among environmental researchers. As a result of the journal's policy to broaden the kinds of articles it publishes, this language is increasing in EE, whether this language is to be applied, to be criticized, or to be questioned. Finally, the primary goals of the community, and in particular that of methodological pluralism, have led the second generation of ecological economists to face the fundamental risk of producing and reproducing a language that, if this trend continues, may reduce the plurality of viewpoints and possibly exclude valuable solutions for environmental problems. The restriction of language may also effect more than ecological economics, since pragmatism can be compatible with both the post-normality set as a foundation of ecological economics and the positivism prevailing in neoclassical economics (and environmental economics in particular). The conundrum we -as ecological economists -have to solve, is that of the extent to which we agree to pursue this path even though it may reduce plurality (and which kind of plurality) within the field, as well as in the production of knowledge for a more sustainable development. This problem also raises the question of the collective identity of ecological economists. I have tackled this collective identity issue by analyzing abstracts published in EE as representative of the evolution of ecological economics discourse. This approach has led to clear results, though it tells us little about ecological economists themselves. For instance, the reasons why authors refer to ecosystem services valuation may differ, and a line must be drawn between research studying or criticizing monetary valuation from those simply applying the valuation of ecosystem services without questioning its methods and concepts.

Paradoxically, one way out of this conundrum lies in the very pragmatism the early ecological economists adopted as a strategy for the community, in bringing together renowned and influential mainstream scholars while encouraging highly innovative niches. The most helpful and effective solutions for sustainability issues may in fact come from these niches. In my view, we should instead support approaches that legitimize new lifestyles that would consume less energy, favor the resilience of ecosystems and preserve worthwhile biodiversity while satisfying the needs of populations. We should also think of new modes of more sustainable development that would be acceptable for emerging countries, which implies questioning the forms of democracies that are best suited to provide for the population, as well as to question issues such as corruption. Research agendas such as the one carried out by the 'degrowth movement,' or on societal metabolism, seem very promising. Yet, they need to question the social desirability of these projects, as well as the institutional, cognitive, organizational, and other lock-in that impede these transitions. My contribution here has been to highlight the risks of adopting monetary valuation of ecosystem services as a privileged way of framing these discussions.

In this line of research, future studies should particularly focus on the ways in which the increase of ecosystem services valuation in the field of ecological economics arises, how it is perceived by ecological economists, and the extent to which this subject is promoted by neoclassical environmental economists. This trend raises important questions about the kind of inter-or trans-disciplinarity we as a community want for ecological economics. If ecological economics has become trans-disciplinary, do we want it to be the discipline of ecosystem services valuation? How do we want to imagine future collaboration between social scientists (in particular economists) and natural scientists (in particular ecologists)? This issue may prove to be extremely problematic in a field that claims to be based on methodological pluralism. Another subject that merits further analysis deals with the ways in which editorial choices are actually made. More attention should be paid to the editorial process as a collective decision-making procedure that results in discourse production. Ethnographical and sociological methods applied to the collective deliberation of editorial meetings would help us to understand the production of discourse and the power issues that arise in the construction of issues specific to EE.

Figure 1 .

 1 Figure 1. Data Sample: Number of Abstracts analyzed by Journal per year between 1989 and 2013

Figure 2 .Figure 2a .

 22a Figure 2. Coevolution of the Discourses in Ecological and Environmental Economics, 1989-2013

Table 2 -Most Significant References Published in Ecological Economics for each Period between 1989 and 2013

 2

Acknowledgements

A preliminary version of this paper was presented at the ESEE 2013 Conference in Lille (18-21 June 2103), at the LEREPS seminar in Toulouse (4 October 2013), and at the EcoEco seminar in Barcelona (16 October 2013). I thank all the participants for their remarks. I also express my gratitude to Tiziano Gomiero, Clive Spash, and Franck-Dominique Vivien who read this text and provided suggestions for its improvement. I also benefited from discussions with Pedro Lomas and Erik Gómez-Baggethun. I am also grateful Pierre Ratinaud and to the members of the Iramutequsers mailing list for their support. Acknowledgements finally go to Cynthia Johnson who edited this text in English.

Appendix 1. Preview of the analyzed corpus Appendix 2. Encoded Forms

1 This question is philosophical and is beyond the scope of science because of the autopoïetic system paradox (also known as chicken-egg paradox): producing truthful knowledge already requires having preconceived what is truth… which follows from the production of truth itself (see [START_REF] Hacking | The social construction of what?[END_REF], for a clear and still current report on debates between realism and constrictivism). As a result, ontological positioning is a matter of a priori scientific positioning. 2 The difference between conviction and persuasion has long been the subject of intense debate. For Pascal (1670), conviction is based on reason, whereas persuasion is based on passion, while for Kant (1781), the former is objective, while the latter is subjective. 3 New topics have been added to the list relevant issues for the field: "alternative principles for valuing natural wealth, integrating natural resources and environmental services into national income and wealth accounts, methods of implementing efficient environmental policies, case studies of economic-ecologic conflict or harmony, etc". 4 Most of them were dismissed in 2002 when Cutler Cleveland was appointed Editor-in-Chief. 5 Respectively, 2.855 and 1.969 for the two-year Impact Factor and 3.732 and 2.970 for the 5-year Impact Factor as of December 2013. The Impact Factor estimates the reputation and reach of an academic review. The index is calculated as a measure of the number of cities an article from the journal gets on average compared to other journals during a two-year period or a five-year period (5-Year Impact Factor). So for year N, the value of the Impact Factor for journal X equals the number citations by other journals of the articles published in X during N-1 and N-2 of N, divided by the number of articles published in journal X in the years N-1 and N-2. 6 There is a fundamental difference between the two tools: Alceste is payware, while Iramuteq is freeware.

Although no user's manual for the latter exists yet, the software can be downloaded on the website of its creators, Pascal Marchand and Pierre Ratinaud (http://www.iramuteq.org/telechargement). 7 Signs are defined as letters (a, b, c), numbers (1, 2, 3), or underscores (_). Every other mark, such as dashes or quotation marks, drops out (e.g. "willingness-to-pay" is processed as "willingness to pay"). However, the association of certain words may have a different meaning than each one separately (as was the case in this example). To solve this problem, every occurrence of the expression is either replaced by an acronym ("wtp", in this case), or linked with underscore (e.g. in the case of "contingent_valuation"). The list of encoded forms is displayed in Appendix B. 8 In this section, the words in italics refer to the words highlighted in the descendent classification. 9 See Costanza's CV:https://crawford.anu.edu.au/sites/default/files/cv/2013/53/costanza_long_cv_6.13.pdf Appendix 3. Correspondance analysis : The two factors explaining the variability of discourses.

Note. This figure represents the variability of the vocabulary used in the discourse of the two fields of environmental and ecological economics. 27.01% of the inertia (first factor) explains the variability on an theoretical/methodological axis. 22.60% of the inertia (second factor) explains the variability of discourses on a empirical domain/scientific perspective axis.


Christian Mühl

Reinhold Scherer

Anatole Lécuyer

Lorraine Perronnet

Moritz Grosse-Wentrup

Fabien Lotte

Which factors drive successful BCI skill learning?

Introduction

• Solving the poor reliability of current BCI requires new research directions, other than signal processing alone • Optimizing BCI training protocols so that users can learn BCI control mastery could be one of them [START_REF] Lotte | Flaws in current human training protocols for spontaneous BCI: lessons learned from instructional design[END_REF] • This poster presents a set of factors which could influence the learning process, and thus could be considered to improve BCI performance of BCI • These factors are based on Keller's theory of motivation, volition and performance [START_REF] Keller | An Integrative Theory of Motivation, Volition, and Performance[END_REF] Challenges and open questions

• Is BCI control similar to any other learning or performance task?

• Which other components we may need to be considered in BCI? Conclusion: While often ignored, motivational and cognitive factors may positively impact BCI performances

• Do these factors apply to BCI as well?

• How to manipulate those factors in BCI?

Increase perceptual arousal by stimulation characteristics

Increase inquiry arousal by task characteristics

Vary stimulation to maintain attention

Attention, a person's curiosity and focus, can be guided by perceptual/intellectual arousal, and the variation of stimulation.

Emphasize the goal in instruction and feedback

Match instructions to the learner's motives and learning style

Increase the familiarity of the learning problem

Relevance, the perceived value of the to-be-learned skill, depends on its compliance with a person's motives or values.

Present clear performance requirements

Enable success opportunities Enable feeling of personal control

Confidence, a positive expectancy for success, depends on the learner's initial mind-set and (the attribution of) success/failure.

Intrinsic rewards by enjoyment of the learning experience

Extrinsic rewards by positive and motivational feedback

Maintain equity with consistent standards and consequences for success

Satisfaction, about accomplishments and learning experience, helps to maintain motivation for current and future efforts.

Make relevant information salient

Mental activities refer to the fact that humans are not passively receiving information, they actively process it (selection, organization and matching to prior knowledge), based on its relevance and saliency.

Match to-be-learned to prior knowledge and skills

Long-term memory is providing prior knowledge and acquired skills for the organization and integration of the learned information.

Cognitive load, the burden on the limited resources of working memory, can be reduced regarding the instruction and presentation of information.