Using facial cues to produce social decisions. A cognitive and evolutionary approach ; Utilisation des indices faciaux lors des décisions sociales. Une approche cognitive et évolutionnaire

Abstract

Face evaluations are a crucial component of social behavior, influencing a large range of social decisions from mating to political vote. Face evaluations are also susceptible to substantial individual differences. In this thesis, I propose that individual differences in face evaluations constitute a promising tool to investigate social behavior through the analysis of variations in the weight granted to different social signals, and notably cooperation- and power-related cues. I apply this approach in two ways. First, I examine the hypothesis that social motivation can be construed as an adaptation to highly cooperative environments. Across six studies, I confirm a central prediction of this theory, by revealing that highly socially motivated individuals grant a higher importance to cooperation-related signals. Second, I investigate the cognitive mechanisms underlying political choices by examining their responses to different environmental signals. In a study on leader preferences in children and in adults, I show that early exposure to environmental harshness is associated with a preference for stronger leaders. Building on these results, I then develop an original theory on political choices stating that leader preferences are biased towards the candidates perceived as the most competent for succeeding in the current context, independently of their leadership abilities. To summarize, my thesis puts forward a new framework to investigate social decisions based on individual variations in face evaluations and sheds light on the cognitive processes underlying social behavior as well as their evolutionary bases. ; Les évaluations faciales sont un élément central des comportements sociaux, influençant un large spectre de décisions, allant du choix du romantique au choix politique, mais sont également le sujet de grandes variations individuelles. Dans cette thèse, je propose que l'analyse des différences individuelles dans l'utilisation de différents signaux sociaux, notamment ceux de coopération et de pouvoir, ...