The Golden Apple of Discord is probably the tale in Greek mythology that best illustrates how conflict is undesirable and leads to upheaval. The story begins with a divine banquet that Zeus organized to celebrate the marriage of Peleus and Thetis (e.g., Graf, 1996). A banquet is a pleasant event and Zeus decided to avoid trouble by not inviting Eris, the goddess of discord. But, as often happens, exclusion leads to frustration and aggression: Eris crashed the party and threw in the middle of the invitees a golden apple with the inscription καλλίστῃ (kallistēi, ‘for the fairest one’). Note that the use of the superlative adjective made it clear that only one was entitled to receive the apple, and three goddesses started disputing such privilege, namely Hera, Athena and Aphrodite. Soon it was clear that no negotiation was possible, that there should be only one winner, and the goddesses resorted to require the judgment of a mortal: Paris the Trojan. Upon bestowing the coveted award to Aphrodite, Paris received both the gratefulness of the goddess of love—under the form of the most beautiful woman on Earth, Helen—and the hatred of the other two, especially Hera, as well as that of all the Greeks, who waged war to Troy at once. An apparently mundane conflict led to bloodbath and destruction in the most famous war of ancient times.

Gabriel Mugny, Conflict and Social Influence

Gabriel Mugny, throughout his long and prolific career, has embraced quite a different view of conflict, and worked relentlessly to uncover the social-psychological mechanisms that lead conflict not only to negative outcomes, but also to positive and constructive consequences. Right from the beginning of his work as a researcher in the early 1970s, Gabriel devoted his famous experiments to point out that conflict is a powerful motor that engages cognitive processes, and that has the potential to elicit intra-individual, inter-individual, intragroup, intergroup and ultimately societal change. Or to impede change. Such an endeavor resulted in two major lines of research that have attracted an impressive number of researchers and—after more than 40 years—are still lively and generating new ideas and new experiments.

The first line of research stemmed from the then-arising field of minority influence, aiming at demonstrating that apparently powerless groups may yield some social influence to the extent that they manage to create some conflict and keep it alive through consistent action (Moscovici, 1976). Gabriel Mugny contributed to this endeavor by devising a theoretical model in which minority sources were represented as having in fact two sets of conflictual relationships, one with the power-holders in a given society (a relation of antagonism) and one with the population (a relation of influence). The importance of such model was to point out that conflict is not related to a uniform behavior and that it can be induced in different manners as a function of the target; in the present case in a rigid, intransigent manner with power-holders and in a flexible, negotiating manner with the population (Mugny, 1982).

Not only can conflict be related to multiple behaviors, but it also results in social influence as a function of rather different socio-cognitive mechanisms. In later work conducted with Juan Antonio Pérez, Gabriel elaborated Dissociation Theory to explain when and how minorities can or cannot have some influence in a complex social reality made of several groups (Mugny & Pérez, 1991). This theory, and its related work, revealed that social comparison with a minority source often leads targets to feel threatened as they may appear too close to a negatively connoted group, which interferes with the validation process that should prompt a close scrutiny of the minority’s message. Thus, when social comparison and validation are non-dissociated, social influence is less likely to occur. However, if social comparison is less threatening, for instance because comparison with the source is less relevant, the two mechanisms are dissociated and conflict may focus targets on message validation, which might result in latent influence. The fundamental contribution of this theory is to make it possible to predict that outgroup minorities—with which social comparison is less threatening—may be more likely to induce influence than ingroup minorities. Again, Gabriel’s work insisted on the importance of studying how conflict is processed in a multiform social space, which contributed to clarifying the differences between ingroup and outgroup minority influence (see Butera, Falomir-Pichastor, Mugny, & Quamzade, 2017, for a recent account).

The second, parallel line of research in which Gabriel Mugny engaged is the one that emerged, also in the early 1970s, from the work on the social development of the intellect carried out with Willem Doise (cf. Doise & Mugny, 1984). This groundbreaking field aimed at showing that social interaction is a crucial factor in the development of children’s cognitive schemes. Central to such development is again conflict, in particular socio-cognitive conflict: Social interaction creates a disequilibrium in the child’s cognitive schemes that requires to reconsider the knowledge at hand, which may result in some progress. Otherwise stated, conflict can trigger cognitive development, which argues for an understanding of cognitive development as a form of social influence. Importantly, a longstanding stream of research has shown that conflict sometimes leads to progress and sometimes not. Over the years, Gabriel has stimulated an impressive number of studies that pointed out how conflict regulation is the crucial factor that determines what the outcome will be (e.g., Mugny, 1985). It is not sufficient to consider the emergence of conflict in order to predict a positive effect on cognitive processes, but one must also take into account how conflict is regulated. Indeed, if conflict is regulated in an epistemic manner, by focusing on the conflicting points of the task that is being discussed, then cognitive progress is likely to ensue. If, on the contrary, conflict is regulated in a relational manner, by focusing on the relative status of the conflicting actors, then cognitive progress is less likely to ensue (see Butera, Sommet & Darnon, in press, for a recent synthesis of these mechanisms).

For many years, these two lines of research developed in parallel directions, although they accumulated convergent results on the essential role of conflict in social influence, be it minority influence or learning in interaction. But at the middle of the 1980s, Gabriel Mugny started to build, with Juan Antonio Pérez, what later would be known as Conflict Elaboration Theory (Pérez & Mugny, 1996). The basic goal of such an endeavor was to account for the massive amount of diverse results that accumulated in the literature on social influence through the notion of conflict elaboration. Indeed, the theory proposed that, when confronted with different influence sources (majorities or minorities, experts or non-experts, ingroups or outgroups) on different tasks (facts, problems, opinion, preferences), people elaborate conflict in different ways. This theory provided scholars with a systematic model that allows to predict the type of influence that would result from a wide array of combinations of sources and tasks, thereby achieving a unitary view of how conflict, once elaborated, leads to change, and what type of change. Or how it leads to no change. The theory also provided a framework that pointed to the unity of the lines of research that Gabriel Mugny had investigated in the past.

The two authors of the present editorial have been fortunate enough to start working as researchers in such a stimulating and vibrant atmosphere. The work accomplished in Geneva in those years, with the close collaboration of a great number of researchers—many of whom are contributing to the present special issue—resulted in a collective volume (Pérez & Mugny, 1993) that has shaped the landscape of the study of social influence in the Geneva School, and has durably influenced our thinking and our way to do research.

From then on, the very notion of social influence has been expanded, and encompassed an ample range of phenomena that involve change, or lack thereof, following a social encounter that requires conflict elaboration. Conflict elaboration has been used to account for a number of important social issues (Butera & Mugny, 2001), to understand the structure of societal influences (Falomir-Pichastor & Mugny, 2004), to explain the emergence of learning in educational settings (Darnon, Butera & Mugny, 2008), and to tackle such fundamental issues as the development of knowledge (Quiamzade, Mugny & Butera, 2013, 2014). The goal of the present editorial is not to retrace Gabriel Mugny’s abundant production—and indeed most of his contributions were not mentioned—but to point out a common feature in the work he has conducted in social psychology: The ability to model and test the importance, role, varieties and functioning of conflict in social influence. Hence, the title of the present Festschrift in honour of Gabriel Mugny. A Festschrift in the International Review of Social Psychology, where Gabriel has served as Editor-in-Chief during two terms.

Structure and Content of the Special Issue

Two articles are concerned with conflict occurring in aptitude tasks, tasks such as problem solving that signal the existence of a correct, or more appropriate answer to reach (e.g., learning tasks). Buchs, Filippou and Pulfrey (2018) study the emergence of competence threat in cooperative learning and the ability of decentering (emphasizing the complementarity of multiple viewpoints) to reduce such threat. Their results showed that students working with decentering, versus not, reported less competence threat, and tended to have a better learning performance. Sommet, Quiamzade and Butera (2017) tackle the question of the representation that people may have of conflict, which is believed to be negative in nature. In fact, their results revealed that conflict can be positively valued by people as a function of its regulation.

Many of the other articles are concerned with opinion tasks, tasks such as the confrontation of opinions whose validity often depends on social consensus and group belonging—i.e. whether the influence source represents a majority vs. a minority, or an ingroup vs. an outgroup (e.g., political opinion, attitude toward refugees, etc.). The debatable nature of opinion tasks makes communication strategies particularly important, and five articles address that. Perez and Molpeceres (2018), discuss a new category of minorities that has emerged in society, namely victimized minorities. These groups, such as for instance Gypsies, convey a moral representation of persecuted minorities and, contrary to active minorities, induce direct but not indirect influence. Papastamou and Prodromitis (under review) present a set of results that point to the importance, when studying social influence, of the evaluation made by targets on the consensus communicated by influence sources. Politi, Gale and Staerklé (2017) integrate models of minority influence with categorization and social identification processes. They aim to understand how members of a national majority become willing to actively challenge political authority by showing solidarity with the refugee minority. Chryssochoou (2018), in a study with Greek participants, showed that in times of crisis and instability of the social order, people who believe in the core values of the system and who are frustrated by its disintegration support more extreme right-wing beliefs and violent practices than both those who challenge the system and those who are supporting it. Finally, Gardikiotis (2017) focuses on people’s perceptions and explanations of majority and minority influence, and on the socio-cognitive processes that underlie them. He showed that thinking as an explanation of influence is more important for a majority (vs. a minority) message and this does not depend on actual cognitive elaboration but rather on self-serving processes.

Opinion tasks, as noted above, involve reflection on identity processes, especially in terms of group belonging, and three articles tackle these important dynamics of social influence. Alvaro and Crano (2017) discuss the relationship between Pérez and Mugny’s (1987) work on the distinction between in-group and out-group minority influence sources, and their model of leniency contract on these same issues. They outline similarities and differences, and ways forward. Sanchez-Mazas (2018) focuses on the very identity of minorities who struggle for recognition. Building on Axel Honneth’s (1996) philosophical theory of recognition, she argues that assuming the very possibility of outgoup influence emphasizes the role of the “voice”, in particular of minorities, as chance to enter into processes of persuasion. Finally, Gabarrot and Falomir-Pichastor (2017) study ingroup loyalty conflict and reveal that the relationship between ingroup identification and intergroup differentiation (stereotyping and prejudice) is a function of distinctiveness threat and ingroup norms.