Sabrina Scherer
email: scherer@uni-koblenz.de

Maria A Wimmer
email: wimmer@uni-koblenz.de

Conceptualising Trust in E-Participation Contexts

Keywords: e-participation, participation, trust, trust model

des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

Several studies have unveiled the importance of trust in e-participation (see e.g. [START_REF] Coleman | Bowling Together: Online Public Engagement in Policy Deliberation[END_REF][START_REF] Grimmelikhuijsen | Effects of Transparency on the Perceived Trustworthiness of a Government O organisation: Evidence from an Online Experiment[END_REF][START_REF] Im | Internet, Trust in Government, and Citizen Compliance[END_REF][START_REF] Kim | E-participation, transparency, and trust in local government[END_REF][START_REF] Seligson | Trust, efficacy and modes of political participation: a study of Costa Rican peasants[END_REF][START_REF] Uslaner | Inequality, trust, and civic engagement[END_REF]). Resulting from the interdisciplinary nature of e-participation [7, p.415], no clear overview of theories and methods applied as well as results achieved so far exist. The complexity of understanding and describing trust in distinct research disciplines [START_REF] Blind | Building Trust in Government in the Twenty-First Century: Review of Literature and Emerging Issues[END_REF][START_REF] Luhmann | Vertrautheit, Zuversicht, Vertrauen: Probleme und Alternativen[END_REF][START_REF] Luhmann | Vertrauen: Ein Mechanismus der Reduktion sozialer Komplexität[END_REF][START_REF] Mayer | An Integrative Model of O organisational Trust[END_REF][START_REF] Mcknight | Trust and Distrust Definitions: One Bite at a Time[END_REF] makes it even more difficult "to follow and [...] to compare [results in trust research] with each other" [12, p.28]. To overcome these challenges, the usefulness of a conceptualisation of trust to form a comprehensive understanding is e.g. argued in [12, p.29, 13, p.974ff, 14, p.36]. This work, being motivated by a research grant by the State Rhineland-Palatinate 1 , aims at building a theoretical model for scoping trust in e-participation contexts with the purpose of investigating the various phenomena of trust from distinct perspectives. The ultimate goal is to derive a trust model for e-participation and to identify the various trust factors in this context. Such a model will help to systematise existing and future studies of trust in e-participation contexts to enable better comparability and better identification of interdependencies of study results and the methods applied thereby from distinct disciplines. This model, together with the systematisation and comparative analysis of existing studies, paves the way for a better understanding of the importance of factors that influence trust in e-participation, which in turn can also inform the design and implementation of e-participation initiatives.

The remainder of the paper is as follows: Section 2 reviews literature to provide the foundations of our research. In section 3, two trust models are exemplified to demonstrate how far they can provide a foundation for a conceptualisation of trust in e-participation. The analysis also shows, which characteristics of e-participation are not represented with these models, and where the trust models need to be extended or adapted for e-participation contexts. As no comprehensive conceptualisation of trust in e-participation could be identified, a trust model for e-participation is proposed in section 4. The model is derived from the findings of exemplifying existing trust models for e-participation. We conclude by arguing the applicability of the proposed model to scope trust in e-participation contexts and by identifying research needs.

2

Literature review

Trust definitions and existing trust models

Due to the complexity of trust as an 'interpersonal and organisational' [8, p.3] as well as multidimensional construct [13, p.976], various attempts of defining [START_REF] Blind | Building Trust in Government in the Twenty-First Century: Review of Literature and Emerging Issues[END_REF][START_REF] Luhmann | Vertrautheit, Zuversicht, Vertrauen: Probleme und Alternativen[END_REF][START_REF] Luhmann | Vertrauen: Ein Mechanismus der Reduktion sozialer Komplexität[END_REF][START_REF] Mayer | An Integrative Model of O organisational Trust[END_REF][START_REF] Mcknight | Trust and Distrust Definitions: One Bite at a Time[END_REF][START_REF] Lewis | Trust as a Social Reality[END_REF][START_REF] Bannister | Trust and transformational government: A proposed framework for research[END_REF][START_REF] Hartmann | Die Praxis des Vertrauens[END_REF][START_REF] Petermann | Psychologie des Vertrauens[END_REF][START_REF] Seligman | The problem of trust[END_REF] and modelling [11-13, 15, 19] trust exist -both originating from diverse disciplines as e. g. sociology, psychology, political science, economics [15, p.138]. Not only between, but also within the diverse disciplines, no congruent definition of trust exists [12, p.31]. Luhmann criticises that the notion of trust would be often used incorrectly, carrying in his criticism, for example, reference to "the research on trust or distrust in politics" [9, p.143]. Following Luhmann, 'issues of trust' might be confused with positive or negative attitudes towards the political leadership or the political institutions, with alienation, with hopes and fears, or with confidence [9, p.143]. The need of one party to trust is defined as a result of some vulnerability to another party; and making oneself vulnerable would mean to take a risk [11, p.712]. Hence, Mayer et al. see trust as "a willingness to take risk" [11, p.712] or a solution for specific risk challenges [9, p.144] in difference to other terms as 'cooperation', 'confidence' and 'predictability' by their definition [12, p.712ff]. Another way of explaining the meaning of trust is by using models to conceptualise the scope of trust [12, p.28]. In this regard, two trust models are presented in this section: (1) Integrative Model of Trust in es. The project is divided into distinct sub-projects, where "mPart -mobile participation of citizens with privacy protection" focuses on the role of trust in e-participation. More information is available at https://www.uni-koblenz-landau.de/komepol/ (access 2014-05-28).

Organisational Settings [START_REF] Mayer | An Integrative Model of O organisational Trust[END_REF] [11, p.711]. The model presents trust as "an aspect of relationships" that "varies within persons and across relationships" [20, p.344]. The model involves "a trusting party (trustor) and a party to be trusted (trustee)" [11, p.711], and it introduces dynamic trust relationships between both parties. Trust is explicitly differentiated from the activity as a result from risk (i.e. Risk taking in relationship -RTR). The decision to take this relationship depends on a function comparing the level of trust to the level of perceived risk in a situation [11, p.726]. The outcome of a risk taking relationship influences factors of perceived trustworthiness (ability, benevolence, integrity) in the next feedback loop -i.e. entering the trust relationship again. Mayer et al.'s model of trust in an organisational setting is visualised in Fig. 1. For details, the reader is referred to [START_REF] Mayer | An Integrative Model of O organisational Trust[END_REF][START_REF] Schoorman | Editor's forum -An integrative model of organisational trust: past, present and future[END_REF]. The complexity of the examined relationships of trust in e-participation makes it necessary to consider the term 'trust' not only from "interpersonal, intergroup, or interorganisational levels of analysis" as it is done in the Mayer et al. model [20, p.345]. Trust in "big ideas, programs, parties, political systems, social changes" as suggested in [17, p.11] To complement these understandings, next subsection reviews definitions and trust models as emerging in e-government research.

Trust definitions and models in e-government research

In e-government research, definitions that base on the perception that some party 'is exploited' by another party are criticised e.g. by Bannister A model differentiating types of trust relevant in e-government is described by Blind [START_REF] Blind | Building Trust in Government in the Twenty-First Century: Review of Literature and Emerging Issues[END_REF]. This model differentiates between political, social, technological, moral, and economic trust as well as trust in government. Another synthesis of trust objects, i.e. the objects towards which trust is directed in a situational context is conducted by Papadopoulou et al. [START_REF] Papadopoulou | What is trust in e-government? a proposed typology[END_REF]. The forms of trust defined there reflect a more detailed differentiation of the model proposed by Blind in regards to technological trust, as trust objects by Papadopoulou et al. are categorised into the following types of trust [19, p.10ff]: trust in stored data, service, information, system, transaction, government organisation, and institution-based trust.

In Korea, a study analysing the implications of Internet usage on trust in government reveals a negative relation of Internet usage in general towards trust in government [START_REF] Im | Internet, Trust in Government, and Citizen Compliance[END_REF]. The authors argue further that the use of e-government could "reduce the negative impact of the Internet on trust in government" [3, p.16]. It is to be tested, whether this also applies to e-participation.

Next subsection provides insights into the status of research on trust in e-participation.

Trust in e-participation research

Current research in trust and (e-)participation consists mainly of studies concentrating on particular aspects, e.g. trust in government or considering the use of electronic tools for political participation. Literature can be separated among researching trust in participation and trust in e-participation.

Trust in participation.

Uslaner & Brown differentiate e.g. the objectives of people for taking part in their communities by types of participation (volunteering, giving to charity, voting, signing petitions, and working for a political party) [START_REF] Uslaner | Inequality, trust, and civic engagement[END_REF]. The authors conclude that "trust plays an important role in participation levels, but contrary to more traditional models, the causal relationship runs from trust to participation" The conclusion from studies is that the systematisation of the full scope and notion of trust in e-participation appears to be difficult. We therefore return to the trust models presented in section 2.1 and exemplify relevant aspects of these models for e-participation with the purpose to analyse their applicability and restrictions and, therewith, to identify amendments of these models to conceptualise trust in e-participation in a more comprehensive way.

Exemplifying e-participation in trust models

The context for exemplifying the models is defined as follows: The trustor is a person interested in taking part in an e-participation initiative. E-petitioning and participatory budgeting were selected for the exemplifications as these are famous and successful e-participation areas, where we gathered a deeper understanding through earlier research. The next two subsections expose the Mayer et al. and McKnight & Chervany models to e-participation. Subsequently, we discuss and reflect the applicability of the models to the e-participation context and derive requirements for a revised model.

Integrative model of trust in organisational settings

The main Risk Taking Relationship (RTR) in our context of study is that the trustor (the participant) takes part in an e-participation initiative. Various individual relationships may be entered as activity of a participation process e.g. to comment, to take part in a poll, to sign a petition, etc. To analyse Perceived Risk, the motivation of the participant for participating needs to be considered (as context information). Here, the motivation is to change a legal/political situation because of personal interests of the participant. Possible direct Outcomes of the RTR are that e.g. a petition may have been refused or accepted. Indirect outcomes are for example satisfaction or dissatisfaction with the process, with the democratic system or the influence achieved, with the institutions and groups involved (e.g. government), with the contributions of others, with the ICT from an emotional point of view, etc. For negative outcomes, potential risks need to be identified. For the aforementioned negative outcomes, the following potential risks could be identified for participants (exemplification; further risks may exist):

• Legal/political situation does not change for the participant and therewith everything that the participant has invested (e.g. time) is lost without any benefit. • User data may be utilised by other parties.

• Participant could experience personal disadvantages as a result of non-anonymous participation through different-minded parties.

If and how far these potential risks are perceived by individual participants depend on the persons themselves and the participation initiative (what impact is possible or expected). The decision to participate might not only base on risks identified. Further a type of calculation between possible positive outcomes (such a concept is not included in the Mayer model) and perceived risks (as condition for participation) might play a role. The relation in the trust model between outcomes and factors of trustworthiness is considering implications on trust as a result of participation. For Factors of Perceived Trustworthiness, involved responsible parties influencing the outcomes of the e-participation initiative could be considered as trustees. To all of them, Trust relationships may exist if the participant as trustor is aware of their involvement.

Trustor's Propensity influences trust relationships. Trust in tools or channels is not considered.

Interdisciplinary model of trust constructs

Dispositional, Institutional

Trusting beliefs and trusting intentions are related to trustees of type 'specific others'. The element 'trusting intentions' implies some dependence of the trustor towards the trustee and rates the willingness of the trustor for being dependent. In our context, this means that the trustor depends on trustees in regards to the risks listed in section 3.1. However, it would also be possible to express that the trustor is dependent in terms of reaching benefits from these trustees. Some benefits can be expressed as a risk by negation. Yet at the same time, benefits can only be achieved if the participant participates. Some possible benefits can be summarised as: The political situation changes corresponding to participants' interests. The participant took an active role in the decision making process. In Mayer et al.'s model, these benefits cannot be regarded explicitly. Trust-related Behaviours focuses on the participation activity and that the trustor depends on the other stakeholders "with a feeling of relative security, even though negative consequences are possible" (as it is defined in [12, p.34f]).

3.3

Discussion of the models' applicability to e-participation contexts

The Mayer et al. model considers influencing factors before a trustor enters a trust relationship. It also shows how outcomes influence again trustor's perception of trustworthiness to the trustee. Factors of trustworthiness can be applied in interpersonal trust relationships and on intergroup or inter-organisational levels [START_REF] Schoorman | Editor's forum -An integrative model of organisational trust: past, present and future[END_REF] so that trust in individual stakeholders and in groups could be examined. The model clearly differentiates trust from influencing factors and from the relationship that is then entered by the trustor. The model shows that, both, the outcomes and the satisfaction with these outcomes influence the assessment of trustworthiness and trustor's further propensity. However, such a feedback to trustor's propensity seems to be missing in this model. gives insights into trust in general others, trust in the situation and structures as well as trust in specific others, the links between them and their influence in the decision to participate. These perspectives to trust from psychology, sociology and social psychology are to be considered when analysing trust in e-participation. So both models are complementing each other to some extent.

Other aspects of trust in e-participation are not explicitly reflected in the two models: A clear one to one trustor->trustee relationship (on an interpersonal level) is often not existent in e-participation contexts, as there is not only one relationship responsible for the decision of a trustor to participate. Instead, different relationships with different trustees can influence such a decision. Using different instantiations of Mayer et al.'s model or different perspectives with different instantiations of the interpersonal perspective of McKnight and Chervany's model would make it possible to analyse the interplay. As the investigation of these interplays is perceived as important for e-participation, we make an attempt to combine and extend the two models. Considering 'taking some risk' in order to trust and to decide to enter a 'risk taking relationship' is difficult to rate as valuable in e-participation. It remains unclear whether a participant will be aware of risks and whether they would influence participation. Also risk of non-participation might be the same as for participation in the case that the voice is not heard and the political/legal situation is not changed. Here, the key question would rather be, if benefits of participation should be regarded in addition to risks. Introducing considerations of benefits could help thinking positive, i.e. that the trustor would not depend necessarily in a negative way from the trustee. Hence, the Mayer et al. model (as it rather investigates a trust-risk analysis) could benefit from integrating possible benefits. Both models consider in general trust of one trustor in a trustee so that the person is the "object of trust, rather than the person in one situation" [12, p.34]. In the e-participation context, the specific situation needs to be considered -i.e. the particular participation experience. Hence the trust object could be 'the trustee in regards to some situational context'. Table 2 shows such trust objects, which have been derived after outcomes have been identified along the ex-emplification of Mayer et al.'s model. These trust objects limit the dependency of the trustor from the trustee. For example, the trustor does not need to trust the government in general but only in proper processing of the participation input. The synthesis shows that both models can provide an appropriate base to analyse trust in eparticipation. However, it is also necessary to add e-participation specific elements as already described above. Next section therefore proposes a trust model for eparticipation based on the two models studied.

A trust model for e-participation

The proposed trust model for e-participation as presented in Fig. 4 From the lessons of exemplifying the trust models in e-participation contexts, we add the perceived benefit of a participation action. We rename the RTR in participation as the action since we embark on a positivist approach.

Trustor's propensity to trust / disposition to trust as characteristics of the trustor describes that "some parties are more likely to trust than are others" [11, p.714]. It indicates the "general willingness to trust others" [11, p.715] that is further modelled with sub-elements 'faith in humanity' and 'trusting stance' [12, p.38f].

Trustor's trust in situation, structures is based on the concept of 'institutionbased trust' [START_REF] Mcknight | Trust and Distrust Definitions: One Bite at a Time[END_REF] with two sub-elements: (i) 'Structural assurance describing that the trustor "securely believes that protective structures -guarantees, contracts, regulations, promises, legal recourse, processes, or procedures -are in place that are conducive to situational success" [12, p.37]. In Fig. 4 some forms of trust with relevance for e-participation are listed in this element. McKnight & Chervany exemplify it as "Using the Internet would have structural assurance to the extent that one believed legal and technological safeguards (e.g. encryption) protect one from privacy loss or credit card fraud" [12, p.37]. Blind sees trust in the Internet (see also [START_REF] Dutton | Trust in the Internet: The Social Dynamics of an Experience Technology[END_REF]) as one form of technological trust [START_REF] Blind | Building Trust in Government in the Twenty-First Century: Review of Literature and Emerging Issues[END_REF].

Fig. 4.

Trust model for e-participation contexts combining the elements of the integrative model for trust in organisational settings [START_REF] Mayer | An Integrative Model of O organisational Trust[END_REF] (solid lines and boxes) and the interdisciplinary model of trust [START_REF] Mcknight | Trust and Distrust Definitions: One Bite at a Time[END_REF] and insights for e-participation (dotted lines and boxes)

Factors of perceived trustworthiness of stakeholders (individuals, groups, institutions) as an attribute of the trustees aims to provide a means for understanding "why a given party will have a greater or lesser amount of trust for another party" [11, p.716]. Participation means to take part and to be engaged in a process or [7, p.402] (individual level). Yet, it may concern also a membership in a group or community [28, p.14] that usually involves a sense of solidarity (institutional/organisational level). The model proposed indirectly deals with this aspect as groups and organisations involved are evaluated for their trustworthiness in this element, which influences trust of participant. Trustworthiness is seen as 'a continuum'. So the trustee cannot be seen as "either trustworthy or not" [11, p. Trustor's trust in e-participation in the specific context considers all involved stakeholders that might be individual persons (as e.g. politicians) or organisations (as e.g. the particular government). This concept also considers trust in particular tools and processes used in the specific e-participation context. Trust in e-participation is a function of (1) "the trustee[s]' perceived ability, benevolence, and integrity" [11, p.720], (2) "the trustor's propensity to trust" [11, p.720], (3) trustor's trust in situation and structures, and (4) tools and processes perceived as functional, helpful and reliable.

Perceived risk "involves the trustor's belief about likelihoods of gains or losses outside of considerations that involve the relationship with the particular trustee" [11, p.726]. We add Perceived benefit as influencing factor for entering the participation relationship that involves the trustor's belief about advantages and positive outcomes.

Participation describes the action that is taken by the trustor as result of trust. Specifics for e-participation, which need to be included, are e-participation activities. Mayer et al. propose the following function comparing the level of trust to the level of perceived risk in a situation: "If the level of trust surpasses the threshold of perceived risk, then the trustor will engage in the RTR. If the level of perceived risk is greater than the level of trust, the trustor will not engage in the RTR" [11, p.726].

Outcomes is conforming to the corresponding concept in Mayer et al.'s model [11, p.728]: Positive outcomes enhance trustor's propensity to trust in others, in the situation and structures, and in specific others. Likewise, perceptions "will decline when trust leads to unfavourable conclusions" [11, p.728]. The outcome of trusting behaviour can influence different trust elements; in which form is still subject of research. For the analysis, the evaluation framework by Macintosh and Whyte is proposed, which proposes socio-technical, project and democratic criteria for evaluating outcomes [30, p.21ff].

E-participation project interventions regard possible e-participation project characteristics that can influence trust. The aim of this element is to provide the possibility to investigate different design decisions in an e-participation project in regards to effects on trust (derived from "Web Vendor Interventions" in [14, p.44]). A starting point for sub-elements can be Macintosh's e-participation key dimensions that are aiming to "capture any political, legal, cultural, economic, or technological factor that stands out so as to make the e-participation a success" [31, p.6].

Concluding remarks

This paper has investigated trust in e-participation contexts. The main aim was to conceptualise an understanding of trust in e-participation contexts. The literature review evaluated models for trust in regards to their applicability to e-participation. Two models have been selected for further examination as these are often cited in literature: a) the Integrative Model of O organisational Trust and the b) Interdisciplinary Model of Trust Constructs. To meet the needs of understanding trust in e-participation contexts, the two models have been combined to 1) investigate trust along the whole lifecycle of e-participation projects with a) and to 2) consider differ-ent trust perspectives (general, system, individual) with b). Some model elements have been revised and amended to better suit the e-participation context. Further research is needed to evaluate the proposed trust model for e-participation contexts and the suggested elements and linkages between them through empirical research and through examination against existing theories in other disciplines as e.g. psychology. In a next step, we will define relevant research questions and categorise them using the elements of the trust model conceptualised for e-participation. As the model is currently only reflecting the participant as trustor, further research will investigate the viewpoints of other roles as e.g. trust of administrative agencies e. g. in the input of the general public necessary for starting an e-participation initiative. Overall, this research is also to be complemented with investigations studying distrust in e-participation and whether the distrust aspect will lead to further revisions of the trust model for e-participation contexts. It needs to be investigated how far people's motivation to participate influences trust and the decision to participate, and if relevant elements should be integrated in the model.

Fig. 1 .

 1 Fig. 1. Mayer et al.'s integrative model of trust in organisational settings[11, p.715]

Fig. 2 .

 2 Fig. 2. Interdisciplinary model of trust constructs[12, p.33]

  [6, p.868]. They further highlight the importance of the economic context for trust in participation. Grimmelikhuijsen & Meijer investigate if and how far prior knowledge and predisposition to trust government influence the relation between transparency and trust[2, p.151]. No support for a general "positive effect of transparency on perceived trustworthiness" was found [2, p.151]: "In sum, "naïve" trustees in government organisations lose their trust if government does not do a good job in creating transparency, whereas being naïve has an opposite effect when it comes to perceived benevolence"[2, p.154]. Another study investigates the hypothesis that public participation enhances public trust. It concludes that "participation affects [public] trust when it produces high-quality services that the public wants" and "enhanced ethical behaviour [integrity, honesty, and moral leadership] on the part of administration"[24, p.276]. Yet, consensus building alone as a result of participation "does not lead to public trust"[24, p.276]. Blind further observed implications of political participation and trust[START_REF] Blind | Building Trust in Government in the Twenty-First Century: Review of Literature and Emerging Issues[END_REF] as demonstrated through a relationship diagram in Fig.3.

Fig. 3 .

 3 Fig. 3. Relationship diagram visualising dynamics of political participation and trust (derived from [8])

  combines the Integrative Model for Trust in Organisational Settings and the Interdisciplinary Model of Trust Constructs. The Mayer et al. model brings in the dynamic relationships in trust and e-participation, i.e. the relationship between trustor and trustee, trust-related behaviour, which results in outcomes, and the assessment of outcomes influencing factors of perceived trustworthiness. The McKnight and Chervany model adds considerations of trust in others, the situation or structures, and the respective relationships.

  721]. Mayer et al. propose ability, benevolence, and integrity as the factors of trustworthiness [11, p.717ff]. The three factors are 'separable' but not unrelated [11, p.720]. Factors of perceived trustworthiness of e-participation tool include electronic and procedural components to the model. In order to consider technology, Plankton and McKnight propose to parallelise "the three technology-related trust beliefs" with "the three most commonly used interpersonal trust beliefs" [29, p.33]. The authors suggest the following analogies: functionality = ability, reliability = integrity, helpfulness = benevolence [29, p.33]. trust in situation, structures Structural assurance, Situational normality of Internet (technological trust) Democracy (political trust) Social context (social trust) Ethics and morality (moral trust) project interventions categorised along e-participation dimensions as e.g. participation level, participation area, technology,…

  is another aspect to be understood. McKnight & Chervany introduce different perspectives in their 'interdisciplinary model of trust constructs' [12, p.31ff], which are: (a) a dispositional perspective regarding trust in general / trust in others, an institutional perspective regarding trust in the situation or structures, and (c) an interpersonal perspective regarding trust in specific others. Five trust types are classified in these perspectives as visualised in Fig. 2: Disposition to trust means the general willingness of trustor to depend on general others [12, p.38]. Institution-based trust means that one believes that favourable conditions exist, which are conducive to situational success in a risky aspect of life [12, p.37]. Trusting beliefs describe "cognitive perceptions about the attributes or characteristics of the trustee" [12, p.36]. Trusting intentions means the willingness of trustor to depend on particular others [12, p.34] i.e. the trustee. Trust-related behaviour describes the act that trustor is depending in a situation [12, p.34]. The arrows indicate how these types of trust influence each other. McKnight and Chervany state that these types of trust are supported consistently by empirical data [12, p.40].

	(b)
	Factors of perceived
	trustworthiness		Perceived Risk
	Ability
	Benelovence	Trust	Risk taking in relationship	Outcomes
	Integrity
	Trustor's
	Propensity
	2 Following Google Scholar, the article has been cited more than 200 times
	(http://scholar.google.de/scholar?cites=904032774768167641&as_sdt=2005&sciodt=0,5&hl
	=de, access 2014-05-20)

Table 1 .

 1 Exemplifying the role of trust perspectives

	Participant trusts in ... Trust perspective
	decision makers.	Interpersonal, Institutional
	platform operator.	Interpersonal
	organiser.	Interpersonal
	tool used.
	other participants.	Dispositional, Institutional, Interpersonal
	democratic structures.	Institutional
	Internet.	Institutional
	others generally.

Disposition to Trust is related to faith in humanity and trusting stance. It is relevant in e-participation to analyse trust in other participants or in the general public. Institution-based Trust, which is related to trust in systems and structures, and which differentiates between 'structural assurance' and 'situational normality', can consider trustor's propensity regarding different forms of trust as suggested by Blind

[START_REF] Blind | Building Trust in Government in the Twenty-First Century: Review of Literature and Emerging Issues[END_REF]

: political, social, technological, moral and economic trust (see section 2.1). Trust in Internet can e.g. be explained with the element 'institution-based trust'

[14, p.43]

. Table

1

exemplifies the roles of different perspectives used in the model for eparticipation (based on an exemplification of the model for e-commerce

[14, p.42]

).

  Another aspect that is not clearly considered is how a concrete technology or a medium of communication is reflected in the Mayer et al. model. Assessing the Interdisciplinary Model of Trust Constructs shows some comparable elements with Mayer et al.'s model (propensity to trust, disposition to trust, factors of trustworthiness and trusting beliefs). Beyond that, the McKnight & Chervany model

Table 2 .

 2 Examples of trust objects in e-participation contexts

	Trustee in regards to...	Trustee
	no manipulation of software (external and internal).	platform operator/provider (PO),
		general public
	no manipulation of hardware (internal).	PO
	no software and hardware failures.	PO
	data are secured in a safe and encrypted environment.	PO
	proper processing of trustor's inputs (e.g. no manipula-	organiser,	responsible	political
	tion, processing in compliance with laws and regulari-	stakeholders e.g. government
	ties, conform to descriptions).
	proper moderating.	organiser (moderator)
	no personal disadvantages.	government, general public
	information provided are correct.	PO, information provider
	proper behaviour of other participants.	general public
	transparency is provided.	organiser,	responsible	political
		stakeholders e.g. government

The research grant "Communication, Media and Politics" (KoMePol) investigates, among other aspects, trust in mediation, perception and processing of politically relevant discoursadfa, p.

1, 2011. © Springer-Verlag Berlin Heidelberg 2011

Acknowledgement. This work was partially funded by the KoMePol project, a Research Initiative (Stage II) of the State Rhineland-Palatinate, Germany. The authors acknowledge the contributions of and express their gratitude to KoMePol project partners for the discussions of the Trust model for e-participation, especially to Rüdiger Grimm.


Anna De Liddo
email: anna.deliddo@open.ac.uk

Simon Buckingham Shum

New Ways of Deliberating Online: An Empirical Comparison of Network and Threaded Interfaces for Online Discussion

Keywords: Argumentation, Computer Supported Argument Visualisation (CSAV), Online Deliberation, Collective Intelligence

des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

Online debate through social media is increasingly used to promote citizens' engagement in policy and decision-making. While common social media websites reach increasing number of users all around the globe, and successfully respond to the demand of scaling up citizen access to public debate [START_REF] Shirky | Here Comes Everybody: How change happens when people come together[END_REF], the way in which those tools support discourse structuring, representation and analysis remains quite limited [START_REF] Sunstein | Infotopia: How Many Minds Produce Knowledge[END_REF][START_REF] Klein | Supporting Collaborative Deliberation Using a Large-Scale Argumentation System: The MIT Collaboratorium[END_REF]. This hampers the very quality of citizen participation to the public discourse and undermines the impact of citizen contributions to e-government and e-participation processes. We argue that one of the main barriers to quality e-participation to public debate is the lack of support for discourse reading and understanding. It is hardly possible for citizens to quickly grasp the main issues involved in an online debate, understand the articulation of the arguments presented, and discovering emerging synergies and conflicts.

In this paper we present results of an exploratory study, which suggests that network visualization of arguments can effectively improve the way in which users read and understand online discourse in at least two ways:

• by facilitating higher-level inferences of how the online discourse contents relate; and

• by supporting the identification of argumentation chains, synergies and contrasts within the discourse.

Moreover, we observed that the dynamic animation of networks adds an element of fun and excitement to arguments exploration. This may play an important role in promoting users' engagements with the online debate, especially crucial for motivating younger citizens.

In the following we detail the results of the study, starting from describing background knowledge and motivating the research in the CSAV (Computer Supported Argument Visualization) and Online Deliberation literature (section 2). We describe the research question and method (section 3), report on the user study (design, and experimentation setting), and describe the tool used to investigate the research question (section 4). Finally we discuss the data analysis and interpretation and present main research findings (Section 5). We conclude by outlining potential applications and future research (section 6).

2

Background and Motivation

Background Knowledge: Computer Supported Argument Visualization for Online Deliberation

The rationale and motivation for this work have roots at the intersection of Computer Supported Argument Visualization (CSAV) and Online Deliberation (OD) research, which studies how computer mediated communication can be combined with argumentation theory to enhance public deliberation. We aim to investigate how multidimensional communication flows (between people, environments, time, topics and points of views) can be translated into coherent discourse and eventually lead groups to better understanding "wicked problems" [START_REF] Kunz | Issues as elements of information systems[END_REF]. Wicked problems are undetermined and complex by nature, and they require deliberative discussions and argumentation to be better understood and tackled. Supporting better understanding and deliberating is the first steps toward the development of informed participation to policy and decision-making, and it therefore sits at the art of e-participation research.

Computer Supported Cooperative Work (CSCW) and Computer supported Collaborative Argumentation have been recognized as two major areas of research that provide support for e-consultation (pp 53, [START_REF]OECD: Promise and Problems of E-Democracy: Challenges of Online Citizen Engagement[END_REF]). Many projects prove the extent of interest and research in this area and its relevance to develop new technologies for eparticipation (for a review of argumentation tools for e-participations see [START_REF] Benn | Argument Visualization for eParticipation: Towards a Research Agenda and Prototype Tool[END_REF][START_REF] Gordon | DEMO-net: D5. 2: Argumentation Support Systems[END_REF]).

CSAV tools have proved to encourage debate and deliberation by citizens on public issues and have been applied f.i for policy formulation to provide a visual medium by which citizens can follow and join in public debates on policy issues [START_REF] Renton | Computer-Supported Argument Maps as a Policy Memory[END_REF]. Tambouris et al. even identify CSAV between the key enabling characteristics to consider when assessing eParticipation projects and tools [START_REF] Tambouris | A Framework for Assessing eParticipation Projects and Tools[END_REF]. Computer Supported Argument Visualization (CSAV) aims to augment the personal and collective ability of users to explore complex problems, make sense of difference in viewpoints, discuss options, and reflect on the implication of those by analyzing and constructing arguments.

CSAV is a research field which has its roots that span several disciplines, such as Philosophy, HCI, hypertext, CMC, and several domain applications, such as design, education, law and public policy [START_REF] Buckingham Shum | The roots of computer supported argument visualization[END_REF]. The idea that people can augment their human intellect and their capability to "comprehend and find solution to complex-problem solving situations" by manipulating explicit and externalized "concept structures" dates to Douglas Engelbart [START_REF] Engelbart | Conceptual Framework for the Augmentation of Man\'s Intellect[END_REF]. Concept Mapping [START_REF] Novak | Learning, creating, and using knowledge: Concept maps as facilitative tools in schools and corporations[END_REF] and Argument Mapping [START_REF] Conklin | gIBIS: a hypertext tool for exploratory policy discussion[END_REF] have been applied to support education and critical thinking and several authors identified "visualization" as an important but unexploited dimension for refining and communicating one's thoughts [START_REF] Horn | Visual language and converging technologies in the next 10-15 years (and beyond)[END_REF]. Argumentation and the associated technological support for argument analysis and construction, have been widely investigated in the two decades from the 70ies and 90ies, when first class researchers in the hypertext community developed prototype tools (between others NoteCards [START_REF] Halasz | Notecards in a nutshell[END_REF], gIBIS [START_REF] Conklin | gIBIS: a hypertext tool for exploratory policy discussion[END_REF] and AAA [START_REF] Schuler | Author's Argumentation Assistant (AAA): a hypertextbased authoring tool for argumentative texts[END_REF]) and carried out pilot studies to explore advantages and shortcoming of this approach [START_REF] Shipman | Formality Considered Harmful: Experiences, EmergingThemes, and Directions on the Use of Formal Representations inInteractive Systems[END_REF] In design rationale studies several limitations have been identified which highlights the difficulty to use computer supported argumentation for design practice, particularly related to the conceptual and time overheads in fragmenting and structuring thoughts before communication. Fisher and al. [START_REF] Fischer | Making Argumentation Serve Design[END_REF] suggest that there are many limitations that need to be overcome to make argumentation (and argumentation tools) serve design; and these concerns have been echoed in [START_REF] Buckingham Shum | Argumentation-based design rationale: what use at what cost[END_REF]. Nonetheless, in another domains such as Technology Enhanced Learning, Public engagement and e-Participation the interest in argumentation and CSAV has persistently been followed, also encouraged by the recognized advantages of this approach in term of support to reflection, knowledge construction and learning [START_REF] Simon | Enhancing the quality of argumentation in school science[END_REF].

Example tools for large-scale deliberation are currently classified as e-participation, edemocracy or e-government systems [START_REF] Macintosh | The emergence of digital governance[END_REF][START_REF] Macintosh | E-democracy and e-participation research in Europe[END_REF] some of which uses CSAV as a way to structure and facilitate citizens consultation [START_REF] Renton | Computer-Supported Argument Maps as a Policy Memory[END_REF] and large scale participation to public debates [START_REF] Klein | The MIT Collaboratorium: Enabling Effective Large-Scale Deliberation for Complex Problems[END_REF].

An established research literature documents the advantages of making the structure and status of a dialogue or debate more visible [START_REF] Buckingham Shum | The roots of computer supported argument visualization[END_REF]. Scheuer and al. [START_REF] Scheuer | Computer-supported argumentation: A review of the state of the art[END_REF] review the state of the art of computer-supported argumentation, which proves the extensive interest and production of research and technology in this field. Scheuer and al. present a rich overview of both the types of argument representations, as well as the variety of interaction designs and ontologies to support argumentation. Several empirical studies are also presented that have been carried out to assess various argumentation systems in different domains. While many of these systems are aimed to support argumentation in a learning context [START_REF] Suthers | Collaborative representations: Supporting face to face and online knowledge-building discourse[END_REF](e.g Belvedere [START_REF] Suthers | Belvedere: Engaging students in critical discussion of science and public policy issues[END_REF] and ARGUNAUTUT [START_REF] De Groot | CSCL'07: Proceedings of the 8th iternational conference on Computer supported collaborative learning[END_REF]); many others have been designed to support argumentation in other fields such as law (Carneades [START_REF] Gordon | The Carneades model of argument and burden of proof[END_REF] and Rationale [START_REF] Van Gelder | The rationale for Rationale™[END_REF]; science (SenseMaker [START_REF] Bell | Using argument representations to make thinking visible for individuals and groups[END_REF], WISE [START_REF] Linn | WISE design for knowledge integration[END_REF]) and decision making (QuestMap, Compendium [START_REF] Conklin | Designing organizational memory: preserving intellectual assets in a knowledge economy[END_REF][START_REF] Buckingham Shum | Hypermedia Support for Argumentation-Based Rationale[END_REF]). We are interested in this last category of argumentation systems and their Web successors which have been designed to support e-democracy and e-participation by promoting citizen engagements in decision-making throughout online discourse processes. These are specifically designed collective intelligence infrastructures and large-scale argumentation systems to structure informal online discussion as argumentation processes and use CSAV to makes visually explicit users' lines of reasoning and (dis)agreements [START_REF] De Liddo | Collective intelligence as community discourse and action[END_REF]. Naturally, the use of semantic networks to provide computational intelligence has now converged with Web Science, resulting in Web 2.0 Argumentation [START_REF] Buckingham Shum | Cohere: Towards Web 2.0 Argumentation[END_REF] and a semantic web standards-based Argument Web [START_REF] Rahwan | Laying the foundations for a world wide argument web[END_REF].

Research Gap and Motivation

Many of these CSAV tools are now available, exhibiting a wide mix of network visualizations and more conventional threaded renderings. Whereas many systems use a common ontology to represent discourse element (such as IBIS [START_REF] Kunz | Issues as elements of information systems[END_REF] or its more design oriented version QOC [START_REF] Maclean | Questions, options, and criteria: elements of design space analysis[END_REF], when it gets to argument visualization there seems to be no agreement on what is the best interface for argument visualization. Deliberatorium uses a linear-threaded visualization [START_REF] Klein | Supporting Collaborative Deliberation Using a Large-Scale Argumentation System: The MIT Collaboratorium[END_REF], while Cohere [START_REF] Buckingham Shum | Cohere: Towards Web 2.0 Argumentation[END_REF] supports a graph visualization of the online discourse. Debategraph1 and CoPe_it! [START_REF] Karacapilidis | Tackling cognitively-complex collaboration with CoPe_it! International Journal of Web-Based Learning and Teaching Technologies[END_REF] enable linear, threaded and graph views. However, to date, we have not yet found a systematic evaluation of the merits or otherwise of CSAV vs. threaded interfaces.

In addition to this, the suitability of graphs as medium to support argumentation has been questioned by some, for three main reasons: complexity of the ontology, number of participants and domain of application. Some researchers argue that the bigger the number of participants to the discussion, and the higher the complexity of the discourse ontology, more clumsy and less usable graph visualizations become (pp.53 [START_REF] Scheuer | Computer-supported argumentation: A review of the state of the art[END_REF]). In addition, there seems to be resistance to the use of graph visualization of arguments in certain domains of application. Hair [START_REF] Hair | LEGALESE: a legal argumentation tool[END_REF] reports on a study in the legal field in which lawyers have expressed a strong preference in favour of linear-threaded text representations of arguments compared to network visualization. It therefore remains unclear what are the advantages and affordances of different graphical representation of arguments to support online discussion and large-scale deliberation. This motivates the research presented in this paper.

An exploratory user study was carried out to compare network visualizations and threaded discussions as the two most commonly used interfaces for argument visualization. We aimed to assess which one of these two visualizations better support online discourse in two main tasks: argumentation reading and understanding. Argumentation reading and understanding are at the cornerstone of effective participation to online discourse, and they also consist of the most prominent users interaction modality. In fact, the internet usage pattern of "participation inequality" [START_REF] Hill | Edit wear and read wear[END_REF] confirms that typically, only a very small percentage of users contributes to a website, compared to vast majority who consume. So, while browsing, searching, reading and writing clearly cannot be divorced from each other, the focus of the study reported here is not on the authoring process, but on the experience and performance of the majority of users who will be reading and searching the online deliberation platforms.

RESEARCH QUESTION AND METHODOLOGY

Does an interactive, self-organizing network visualization of arguments provide advantages over a more conventional threaded interface for reading and search? The following research questions was formulated: RQ: What are the recognized advantages of threaded and network visualization of arguments for supporting online discourse reading and understanding? A grounded theory analysis has been conducted to study the use of different graphical interfaces for the representation of arguments, and to assess to what extend these affect the way in which users read and understand the online discourse. Grounded Theory is a qualitative research method which has been widely used in HCI to provide insights on people's views, behaviors, understanding and experience with technology [START_REF] Glaser | The discovery of grounded theory; strategies for qualitative research[END_REF]. Very recently the discussion has been revamped on what are the nuances and innovation to the method that may help to respond to the increasing request and diffusion of qualitative research studies in HCI [START_REF] Brown | A grounded investigation of game immersion[END_REF].

We took a 'constructivist' stance to grounded theory which aims at creating a description of the context rather than discovering a description of it (objectivist approach). We started by keeping a Glaserian approach to data analysis and applied open coding of the data trying not to be influenced by prior ideas or extant theories. The initial open coding phase was performed on transcripts of the screencast video of users' interaction in the experimentation. Video clips and transcripts were analyzed and coded in an unfocused manner. While reiterating the coding from one user experimentation to the following, we moved progressively to a more focused coding in which specific concepts and themes started emerging. From this analysis several categories emerged which provided the building blocks of our findings, and the main pillars of our narrative of the analyzed phenomenon. The coding process generated over 350 codes, which have been edited and merged in several revising cycles, and then have been grouped into main sub-categories (23 in total) and higher-level categories of analysis (9 in total). The main higher-level categories emerged provided a taxonomy of the main components/variables which effect users capabilities to read and comprehend online argumentative discussion. The 9 categories have then been ordered on the base of what were more significant in terms of three metrics: number of quotations per code (N. of Videoclips/Quotation), number of participants who experienced the event captures by the code (N. of People affected), and time of interaction per code. As a result three main higher-level code categories emerged as key factors affecting users interaction and these have been used

as metrics to access users performance with the two interfaces (see section 5). We then developed a narrative around these 3 emerging themes, but also around events and findings, rooted in the in depth observation and analysis of the interaction. This allowed us to draw some conclusions on what are the recognized advantages of threaded and network visualization of arguments to support online discourse reading and understanding.

User Study

Goal, Design and Participants

We studied an heterogeneous group of researchers and practitioners in Higher Education engaged in the use of a collective intelligence tool for collaborative argumentative discourse and knowledge construction. An exploratory user study was run to observe users' performance under three information-seeking tasks, and compare their performances using two different user interfaces for arguments visualization (threaded vs network visualization of arguments). Participants were divided in two groups of 5 (Group1 and Group2). The 10 subjects were drawn from the members of different Open University departments, so with widely mixed IT expertise. They were randomly allocated to the two different groups, but we verified post-hoc that IT expert/non ex-pert ratio in each group was approximately the same. The median age was 40 (with range from 32 to 48) with the majority of users being either native or near-native English speakers.

Online Environment: The Evidence Hub

The online discussion tool used throughout the study was the Evidence Hub system [START_REF] De Liddo | The Evidence Hub: harnessing the collective intelligence of communities to build evidence-based knowledge[END_REF]. The Evidence Hub is a collective intelligence and online deliberation tool to support argumentative knowledge construction by crowdsourcing contributions of issues, potential solutions, research claims and the related evidence in favor or against those. The Evidence Hub is particularly oriented to support community of practitioners to build evidence-based knowledge about specific key challenges that are set up to the community. This key challenges can then be addressed by tackling specific sub issues, that the community contribute to add to the system. Each sub issue can then be tackled by proposing solutions to it, or by sharing specific research claims that can help tackling the issue. Finally potential solutions and research claims can be debated by the community by advancing evidence in favor or against those and by providing relative resources backing them up. By scaffolding users contributions in this way, the Evidence Hub aim to effectively crowdsource and support large-scale deliberation in e-democracy and decision-making processes. To allow comparison between users interaction with two graphical representations of arguments, two different versions of the Evidence Hub have been set up which used different user interfaces for arguments visualization. The two versions of the Evidence Hub pointed at the same database to ensure that participants in the two groups would receive the same quantity and type of information.

The Linear-threaded Interface for Arguments Visualization

The linear-threaded interface was used by Group1 (Figure 1). This interface for arguments visualization is similar to the most common threaded online discussion interfaces to support argumentative discourse activities. It consists of a classical threaded visualization in which issues set the focus of discussion (title of the page in Figure 1), and then potential solutions are listed below (light bulb icons are placed before each solution). Each solution can then be expanded on demand. The progressive indentation of text shows the supporting and challenging evidence for a solution, and the re-sources supporting evidence (Figure 1).

The Network Interface for Arguments Visualization

The network interface was used by Group 2: This consists of an argument map built by following the modified IBIS, PHI model of arguments [START_REF] Mccall | PHI: A conceptual foundation for design hypermedia[END_REF]. Each statement added to the discussion is here represented as a node in a semantic graph structure (Figure 2). In this visualization, node icons and colors represent the rhetorical role of the statement in the discussion: issues are characterized by a red question mark icon in a dark turquoise node (yellow in Figure 2 because the node is selected); solutions are distinguished by a light bulb icon (see light green nodes), while pro and con are characterized by purple nodes and are connected with a green link or red link to respectively indicate "supporting" or "challenging" relations.

The network visualization of the Evidence Hub is build with a Java Applet, which lays out the nodes dynamically, and following a gravitational algorithm. This adds a specific animation component to most common argument network visualization tools.

Data Analysis and Results

The experimentation design aimed to provide an answer to the RQ by focusing on three specific information-seeking tasks (for issues of space we skip detailed description of the tasks):

1.

Identifying solutions to an issue (Task1) 2.

Identifying synergies between solutions (Task 2) 3.

Identifying contrasts in the wider debate (Task 3) The tasks lasted about 2 to 3 minute and required users to scan 1-3 Webpages (about 1500 -4000 words) depending on the task. The three higher-level class of codes emerged from the grounded theory analysis of the user-interaction videos were used as metrics to compare the user's performance across the three tasks. The metrics are: Task Accomplishment; Data Model Interpretation and Emotional Reactions to the two interfaces. From the grounded theory analysis, these metrics have been found to represent the most relevant factors affecting interaction and therefore have been used to assess users' performance with the two interfaces. In the following we analyze and compare users' performance by focusing on each of these metrics and providing users code to motivate our understanding.

Task Accomplishment

Four main sub-categories of accomplishment emerged form the coding: Accomplished easily, Accomplish but incorrect, Not accomplished, and Give Up the task. From the analysis of the quotations and of the screen capture video of the interaction we found that the main reason of failure was task's understanding. Most interaction events coded as "Accomplished but incorrect" were reported in Group 1. The linear structure of the interface is not designed to help interconnecting and comparing content and this has proved to be a burden to the user. As a consequence of this limitation, users who interacted with the linear interface focused more on issues of content's style and validity, rather than on the argumentation process, which lead to digressions and incorrect responses. On the contrary the interaction events coded as "Accomplished easily" were mainly experienced in Group 2. This is mainly due to the visual hints provided by the network representation. Specifically, links labels and colours seemed particularly predominant in determining success. We noticed that, the users who accomplished the task easily usually relayed on links colours and label, and paid less attention to the iconography of the nodes. The number of links (connections density) also proved to be a very effective way to provide answers to the task.

Comparing Data Model Interpretation

In order to compare linear and network visualization of arguments in term of how they supported Data Model Interpretation (DMI) we first identified the emerging codes related to DMI and merged them under the following 5 main classes (1. get the model right, 2. get the categories right, 3. get the model but is unsure, 4. misinterpret categories, 5 does not get the model at all). We then analysed the interaction events and quotations for each main class.

Results show that DMI was better supported by network visualization of arguments. Category misinterpretation and uncertainty in data model interpretation tend to occur more frequently in Group1 than in Group2, while network visualization of arguments seems to support a complete and correct understanding of both categories and data model. Findings suggest that one possible motivation for this is that argument maps provides examples of how the content of discussion is interpreted in the data model supported by the Evidence hub. In this way users can learn by example ("let's see what other people have put under this category" -P8) and at each exploration of a new argument map they reinforce their understanding of the data model ("this is my solution and this evidence support the solution, and these two nodes challenges it...the clue is the red "challenges" link -P7)".

Comparing Emotional Reactions

Emotional reaction to the graphical representation of arguments is another emerging category that we used to measure users satisfaction and emotional attitude toward the two proposed interfaces. Results show that a general sense of surprice and positivity toward the network visualization was recorded, which easily sparks into linkeness and even exhitment ("ahhh so fabulous!"-P7; "wow this is amazing!"-P6). This postive emotional reaction also seems to be associated to an increase of user' s confidence with the tool ("I feel confident, I'm pretty sure this is the answer"-P7). The main object of positivity toward the network visualizations was the self-arranging graph applet. The Applet presents argument maps as floating nodes and edges, slowly moving and arranging on the screen ("it is like a jelly, it is so fantastic!"-P7; "it is all shifting! It is interesting… I quite like that!"-P8). Movements provoked surprise and excitement and it was also recognized as a useful information feedback. By looking at the floating network, users understood that the map was not static and they could move nodes around and play with it. Users reported that they mostly enjoy this feature. In summary, findings suggest that: moving arranging, zooming and pinning are the network features which most augment users confidence and satisfaction with the tool. On the contrary emotional reactions to the linear interface for arguments visualization were general skepticism and dissatisfaction, and sometime also decayed to confusion and feeling lost ("I think I am lost"-P1; "I am now really annoyed.. because I haven't worked out how to do it" "that is the all page I am looking at?…ohhh ok I give up!"-P5). Some users explicitly identified the cause of their frustration and said that they needed "too many clicks" to seek information and frequent "change of context" which often provoked disorientation.

Contributions and Future Research

The grounded theory analysis of the experimentation's video showed that different graphical interfaces for the representation of arguments strongly affect the way in which users read and understand the online discourse. Network-like representations and visual hints such as network structure, iconography, links' labels and colors seem to facilitate the identification of argumentation chains, thus supporting indirect connection and higher-level inferences of how the content connects. The results show that data model interpretation is also improved by argument visualization. Notably, exposing the data model in form of argument maps appears to enable learning-byexample mechanisms, whereby users reinforce their understanding of the data as they navigate through the user interface. Finally there is an element of fun and excitement associated to dynamic network visualization of arguments. This may suggest that this type of arguments visualization could be useful for e-participation processes in which the element of "play" and positive emotional reaction are key factors to success. This paper shows promising results on the capability of network visualization of arguments to support reading and sensemaking of online discourse activity. Of course the challenge for e-participation is: how can we move from lab experiments to real world setting and scale the use of CSAV from small group to collectives. Future research will be devoted to explore the use of CSAV and other form of visual analytics to improve users' engagement and sensemaking of large-scale online deliberation processes.

Figure 1 .

 1 Figure 1. Linear-threaded Interface for Arguments Visualization

Figure 2 .

 2 Figure 2. Screenshot of the Network Interface for Arguments Visualization

DebateGraph

2013: Web tool for the visualization of idea and debates http://debategraph.org

Acknowledgements

The authors thank the support of Catalyst (FP7 program -grant agreement #6111188) under which this work has been finalised.