The Evolutionary dimension of Trust and its effects on cooperation

Abstract

Human social life is sustained by cooperation in a different way with respect to other species. Scientists have investigated human cooperation from different points of view (Trivers, 1971; Dawkins, 1976; Axelrod y Hamilton, 1981; Axelrod, 1984; Caporael et al., 1989; Boyd & Richerson, 1990; Wilson & Sober, 1994; Bergstrom, 2002; Boyd et al., 2003; Gintis et al., 2003; Bowles & Gintis, 2004; Gintis et al., 2008; Boyd et al., 2010) but many questions about the evolution of cooperation remain open. In this dissertation the cooperative relationships are analyzed emphasizing its intrinsic link with trust relationships. Why do we cooperate? What is the influence of trust on cooperation and which role does human evolutionary history play in this puzzle? Considering the social forms our ancestors lived by, it is possible to think in certain cognitive and psychological traits that might have a key importance in order to understand the relationships of cooperation and, in a wider sense, the social relationships it made possible. The goal is, in short, framing social relationships in an evolutionary framework in order to explain the social behaviors of nowadays. Content of research This work attempts to answer these questions firstly on the basis of the relation between the evolution of human sociality and cognition, as a hypothesis to be tested in the following studies. From this perspective and using a multidisciplinary methodology including Sociology, Psychology and Anthropology, a research plan was designed in order to further examine these topics. This dissertation starts with a critical review of some previous studies that relate the social behavior in primates to the evolution of the neocortex –Dunbar’s Social Brain Hypothesis (Dunbar, 1992; Dunbar, 1998; Dunbar & Shultz, 2007; Shultz & Dunbar, 2007; Dunbar, 2010). This review shows the need for a more nuanced approach in order to explain this dependence because of the enormous complexity of human social relationships. To achieve this goal, the analysis of the psychological mechanism of trust offers a huge interest. However, Dunbar’s studies, especially those that relate human social groups to cognitive ability, are continuously in the background throughout all this work. Next, a theoretical framework is introduced to characterize trust and the factors that influence it (Parsons, 1970; Barber, 1983; Good, 1988; Yamagishi, 1998; Glaeser et al., 2000; Uslaner, 2002; Six, 2005; Bjørnskov, 2006; Hardin, 2006), as well as their possible configuration in an evolutionary environment. On the basis of this theoretical framework the subsequent empirical work is designed, always keeping in mind the assumption that humans have a social behavior widely influenced by a context of relationships within small groups. They are the social configuration humans lived most of their evolutionary history. In the theoretical framework the elements that make up trust, its typology and its possible configuration in the evolutionary history are explained. This work is the substrate used to groundthe analysis of trust and cooperative behavior carried out in the following empirical works. These empirical studies follow an original plan, grounded in a literature review (Fey, 1955; Rosenberg, 1957; Wrightsman, 1964, 1974; Rotter, 1967; Survey Research Center, 1969; Christie & Geis, 1970; Johnson-George & Swap, 1982; Rempel et al., 1985; World Values Survey Association, 2009), which involves the development of new questionnaires to measure the level of general and personal trust in a group. In addition, an experimental game –a prisoner's dilemma with some variants– is included in order to show the effective cooperative behavior of participants. The game is played in conditions of trust and non-trust among the members of the group. The pilot study is initially conducted in two different groups. The results already show the influence of close relationships of personal trust in cooperation and the interest of analyze trust networks (Radcliffe-Brown, 1940; Barnes, 1954; Milgram, 1967; Mitchell, 1969; Wasserman & Faust, 1994; Molina, J.L., 2001; White & Harary, 2001; Newman et al., 2003; Freeman, 2004; Eguíluz et al., 2005; Fowler & Christakis, 2010) more deeply. The results of this work are confirmed in a subsequent similar study with other more numerous and more comparable groups. The new results show how cooperation relates largely to an affective commitment of reciprocity that comes from personal trust, as adaptive element towards a more successful cooperation, even in conditions of anonymity, and despite the possibility of causing a cost in individuals in the short term. In addition, the study includes an analysis in depth of these groups’ trust networks to analyze the importance that certain topologies of trust networks can have on the general cohesion of a group. The last part of the dissertation shows a more anthropological perspective with the completion of fieldwork in two areas characterized by a great ethnic diversity: Northern Ghana and Oaxaca, in Mexico. These locations allow study how groups interact and why they keep their ethnic identities despite a history and a territory in common. To examine whether the personal trust mechanisms present at an individual level can be also extended to larger groups or societies is aimed. In this case, in addition to the direct observation of groups and the inclusion of its historical, social, economic and political context, interviews and personal networks of cooperation are used. The work of Ghana (Rattray, 1931, 1932) Syme, 1932; Tait, 1961; Hilton, 1962; Hart, 1971; Drucker-Brown, 1975, 1992; Primmirat, 1979; Laari, 1987; Awedoba, 1989, 2001; Wilks, 1989; Assimeng, 1990; Kotey, 1995; Schlottner, 2000; Oppong, 2002; Tonah, 2005) shows the context of groups and the features of their trust networks of trust and cooperation are explained . In this work, the effectiveness of ethnic diversification as a means to create small groups more resilient when face with difficult environments is shown. The adoption of cultural forms that allow extend personal trust in larger collectives is also presented. The last work compares the Ghana results with those of Mexico (Chance, 1979; Zeithin, 1990; Campbell, 1993; Oseguera, 2004; Queen Aoyama, 2004; Barabas, 2006, 2008; Trejo Barrientos, 2006; Spores, 2008; Joyce, 2010; Nahmad Sitton, 2013), in a cross-cultural analysis to identify possible "universal" elements in trust and cooperation networks, and also cultural influences. Conclusions The previous works show that trust is a cognitive and psychological mechanism anchored in human evolutionary history. Their evolutionary origin is supported by the results of this dissertation: to demonstrate the higher influence of personal trust than general trust in fostering cooperation. Close relationships are needed for personal trust and they require small groups for its emergence –given the cognitive and temporal constraints required in order to keep such relationships with a larger number of people. Close relationships also involve an emotional dimension –a most primitive mechanism in humans. In fact, small group dynamics was found both in experimental games and in fieldwork. Personal trust also plays a role in large scale societies, where individuals continue to create their small groups in all areas of their life. However, in those societies where survival is more difficult and resources scarce certain cultural tools (such as values or norms) appear whose function is to extend personal trust to a greater number of people: groups such as ethnic groups, clans, lineages, families, commonalities, municipalities (as in the Oaxaca case). Thus, culture provides the necessary mechanisms to create strong bonds of cohesion based on emotional elements beyond the small group. Greater cohesion and a more open attitude of trust arising from such cultural tools help at time to face environments more efficiently. Thus, it could be predicted that more difficult environments show a greater group diversification. In addition, the comparison of Ghana and Mexico results allows a deeper analysis of the common elements of trust and cooperation networks -their universal aspects-: small groups and different levels of emotionality implied in the bonds of trust; and cultural elements that are suited to the historical context and the economic situation of groups, to create a more or less cohesion of its members according to their needs. Thus, in addition to identify in the field several indicators to measure trust, more effective cultural forms to foster cooperation is also identified: the values and the sense of identity of group membership, instead of formal regulations and authority.