Les comportements sociaux coopératifs sont longtemps restés un obstacle aux modèles de choix rationnel, obstacle qu'incarnent des dilemmes sociaux où un individu suivant son intérêt personnel est incité à exploiter la coopération d'autrui à son seul avantage. Je détaillerai tout d'abord comment la coopération peut apparaître un choix sensé lorsque elle est envisagée dans un contexte naturel et réel. Un regard à travers l'anthropologie, la psychologie et la neurobiologie conduit à appréhender la coopération davantage comme une adaptation et un apprentissage que comme un défaut de rationalité. Les émotions jouent un rôle essentiel dans ces processus, et je présenterai en quoi les exprimer aide les êtres humains à se synchroniser et à coopérer. Le sourire est souvent invoqué comme exemple d'un signal universel de coopération et d'approbation, une propriété intimement liée à son expression répétée lors de tâches collaboratives. Malgré tout, on en sait encore peu sur la manière précise dont le sourire et les autres expressions interviennent dans la prise de décision sociale, et en particulier sur le traitement des situations d'incongruence où un sourire accompagnerait une défection. Ce point est le cœur de l'étude expérimentale que je rapporte dans ce manuscrit. J'ai réalisé deux expériences confrontant les participants à un dilemme social dans lequel ils pouvaient investir une somme d'argent auprès de différents joueurs informatisés susceptibles de se l'accaparer, ou, au contraire, de la rétribuer avec intérêts. Les joueurs virtuels étaient personnalisés par un visage dont l'expression pouvait changer après le choix du participant: certains affichaient ainsi des émotions incongruentes avec leur ``décision'' subséquente de rétribuer ou non l'investissement du sujet. Malgré les différences méthodologiques, ces deux expériences ont montré que les expressions incongruentes altéraient la capacité des participants à jauger la propension des joueurs virtuels à rétribuer leurs investissements après une ou plusieurs interactions. Cet effet s'est manifesté tant au travers de rapports explicites que dans les investissements effectués. Dans leurs détails, les résultats de ces expériences ouvrent de nombreuses perspectives expérimentales, et appellent à la construction d'un modèle unifié de la décision sociale face-à-face qui intégrerait les nombreuses connaissances apportées ces dernières années par l'étude des grandes fonctions cognitives, tant au niveau expérimental, théorique que neurobiologique. / For few decades, rational choice theories failed to properly account for cooperative behaviors. This was illustrated by social dilemmas, games where a self-motivated individual will be tempted to exploit others' cooperative behavior, harming them for his own personal profit. I will first detail how cooperation may rise as a reasonable --- if not rational --- behavior, provided that we consider social interactions in a more realistic context that rational choice theories initially did. From anthropology to neurobiology, cooperation is understood as an efficient adaptation to this natural environment rather than a quirky, self-defeating behavior. Because pertinent information is often lacking or overwhelming, too complex or ambiguous to deal with, it is essential to communicate, to share, and to trust others. Emotions, and their expression, are a cornerstone of humans' natural and effortless navigation in their social environment. Smiles for instance are universally known as a signal of satisfaction, approbation and cooperation. Like other emotional expressions, they are automatically and preferentially treated. They elicit trust and cooperative behaviors in observers, and are ubiquitous in successful collaborative interactions. Beside that however, few is known about how others' expressions are integrated into decision making. That was the focus of the experimental study I relate in this manuscript. More specifically, I investigated how decisions in a trust-based social dilemma are influenced by smiles which are either displayed along a cooperative or defective behavior (``congruently'' and ``incongruently'', resp.). I carried out two experiments where participants played an investment game with different computerized virtual partners playing the role of trustees. Virtual trustees, which were personalised with a facial avatar, could either take and keep participants investment, or reciprocate it with interests. Moreover, they also displayed facial reactions, that were either congruent or incongruent with their computerized ``decision'' to reciprocate or not. Even if the two experiments presented some methodological differences, they were coherent in that they both showed that participants were altered in remembering a virtual trustee's behavior if the latter expressed incongruent emotions. This was observed from participants' investments in game, and from their post-experimental explicit reports. If many improvements to my experimental approach remain to be done, I think it already completes the existing literature with original results. Many interesting perspectives are left open, which appeal for a deeper investigation of face-to-face decision making. I think it constitutes a theoretical and practical necessity, for which researchers will be required to unify the wide knowledge of the major cognitive functions which was gathered over the last decades.

Bakgrunden för denna studie är problematiken kring beslutsfattande. Tidigare forskning visar att en individ dagligen fattar en mängd medvetna och omedvetna beslut. Dessa beslut faller sig olika utefter vilka erfarenheter, preferenser och känslor individen har och hur detta påverkar individen vid köp av dyra sällanköpsvaror. Syftet med studien är att identifiera faktorer och personlighetstyper som influerar köparens beslut gällande dyra sällanköpsvaror. / The aim of this study is to identify factors and personality characteristics influencing the buyer's decision regarding expensive durable goods. The findings suggest how to apply knowledge and awareness of the decision process in on-site presentation to improve the efficiency of the selling process from the sellers’ perspective.

Made available in DSpace on 2016-03-15T19:39:36Z (GMT). No. of bitstreams: 1 Camila Campanha.pdf: 2234537 bytes, checksum: 330a99b6a7ecb7751a711132a17ecb0b (MD5) Previous issue date: 2010-12-14 / Fundo Mackenzie de Pesquisa / Decisions engage careful consideration of the risks and benefits involved in a particular choice. As we live in society, these choices are not only related to our personal interests. Therefore, social interaction has an important role, because the other is part of the context in which we evaluate decisions. Previous studies show the importance of trust and empathy in decision-making processes. In fact, Boudreau, McCubbins and Coulson (2009) showed that trust in another person interferes with behavioral response and also in event related potentials recorded during the test. However, as in other studies, trust was studied by the instruction given to participants that they will base their choices by reports made by another human being - unknown person. The use of an unknown person limits the interpretation of the role of trust involved in decision making processes. Thus this study aims to investigate the decision making processes in a task in which the participant brought to the lab a person (a trusted friend) that act as reporter. In addition, there are few studies investigating event-related potentials in tasks of social decision. Therefore, this study aim to understand the role of trust in decision-making by analysis of behavioral performance in an adapted version of the Ultimatum Game task and also investigate the event related potentials collected simultaneously. Among the main findings, we found a change in the perception of fairness (in fact there was no difference) and, consequently, a change in decision-making with more acceptance of proposals on the condition of interaction with the trusted person than other proposers. Moreover, the P3, FN and LPC potential were modulated by the impact of trust, and by moral internalization, and differed between genders. This study may increase knowledge about the neurobiological bases of behavior and decision making processes involving social interaction, trust and empathy. / Decisões envolvem considerações cuidadosas sobre os riscos e benefícios envolvidos em uma determinada escolha. Por vivermos em sociedade, estas constantes escolhas estão relacionadas não só aos nossos interesses pessoais. Nesse sentido, a interação social tem um importante papel, pois o outro faz parte de um contexto no qual avaliamos possíveis decisões. Estudos prévios mostram a importância da confiança e da empatia em processos de decisão. Nessa direção, Boudreau, McCubbins e Coulson (2009) mostraram que a confiança no outro interfere na resposta comportamental e também nos potenciais cognitivos registrados durante o teste. Entretanto, assim como em outros estudos, a confiança foi estudada pela orientação ao participante de que este estaria sendo orientado por outro ser - humano uma pessoa desconhecida). O uso de uma pessoa desconhecida limita a discussão a respeito do papel da confiança envolvida em processos decisórios. Dessa forma este estudo busca investigar os processos decisórios em uma tarefa na qual o participante levou ao laboratório uma pessoa (amigo de alta confiança) que funcionará como propositor. Além disso, ainda são poucos os estudos investigando potenciais relacionados a evento em tarefa de decisão social. Com isso, este estudo buscou compreender o papel da confiança em processos de decisão analisando o desempenho comportamental em tarefa adaptada do teste Ultimatum Game e também os potenciais cognitivos coletados simultaneamente. Entre os principais achados, encontrou-se uma alteração na percepção de justiça (o que na realidade não havia diferença) e, por conseqüência, uma alteração na tomada de decisão com maior aceite de propostas na condição de interação com a pessoa de confiança em comparação com os outros propositores. Além disso, os potenciais P3, FN e LPC foram modulados pelo impacto da confiança, pela interferência da internalização moral e apresentaram diferenças entre gênero. Este estudo pode aumentar o conhecimento sobre as bases neurobiológicas e comportamentais de processos decisórios envolvendo interação social, confiança e empatia.

Made available in DSpace on 2016-03-15T19:41:23Z (GMT). No. of bitstreams: 1 Camila Campanha.pdf: 2524288 bytes, checksum: 55de5a887b8f719667a31b6b080b9b55 (MD5) Previous issue date: 2014-06-16 / Fundo Mackenzie de Pesquisa / Because we live in society, constantly choices are relate not only our personal interest. Recent study (CAMPANHÃ et a, 2011) was verify that he participants realize your friends as more fair than an unknown, showing a unreleased information in the social decision making studies. Preview studies demonstrated the relation between an event-related potential, the Medial Frontal Negativity (MFN), in the unfair offers to unknown proposers, however not by friends. Beside this, the sLORETA analysis revealed a significant difference in the medial prefrontal cortex region - related to empathy and metallization - in the unknown condition when compared the unfair offers with the fair offers, however, not in the friend condition. The difference in the unfair perception related to the proposer introduces a new question about the widely accept altruistic punishment concept. Therefore, the present study aimed (i) to investigate the empathy and gender impact as modulators factors in the Ultimatum Game (UG) when the interaction is with a trustworthy person (friend) and an unknown; (ii) to investigate the behavior characterized as altruistic punishment in the adapted UG in two different interaction context. Thus, was realized two experiments. The first one, similar the anterior one, the participants played the UG with a friend and an unknown. Therefore, we controlled the empathy level (low and high) and gender. In the second experiment, beside the gender and empathy level control, the participants had to decide whether accept or reject the share proposals the R$120,00 reias between three persons: the proposer, the participant and a third person ( dummy ), that was a friend and a unknown in the first part of the game. In the second part of the game, the participants only decide whether accept or reject in the place of the friend and an unknown and don´t had any earnings and any loss involved. As results, was observed large rate of rejection the unfair offers proposed by an unknown than by the friend. The friend was judged as more fair. Also, was observed that the men reject more offers made by an unknown. The participants with high level of empathy rejected more unfair offers that was made by an unknown and presented the MFN amplitude more negative for unknown proposer and more positive for friend proposer. The men with high level of empathy presented the MFN amplitude more negative for the unknown. In the second experiment, the participants rejected more unfair proposals for both kind of third part. The MFN amplitude was more negative when the proposals were unfair for both (the participant and the third part). As well as women and for high empathy level participants. In the second part of the experiment two, the participants benefited more the friend. The MFN amplitude was more negative for the men in the interaction unknown proposing to the friend. The women presented more large P3 amplitude in the interaction unknown proposing to the friend. Taken together, the results suggest that the empathy and gender impact when a friend is involved. Beside this, the personal gains and losses involvement also was an important factor in the fairness perception. The present study corroborates with preview studies that showed the fairness perception modulated the trust and that he empathy and gender are factors with more or less impact in different context. / Por vivermos em sociedade, constantes escolhas estão relacionadas não somente aos nossos interesses pessoais. A diferença na percepção de injustiça em função da Amizade em estudos utilizando o jogo Ultimatum Game (UG) introduz uma nova questão com relação ao conceito amplamente aceito de punição altruística. Dessa forma, a punição altruísta e o impacto dos fatores gênero e nível de empatia como moduladores da percepção de injustiça precisam ser investigadas nas relações interpessoais. Nesse sentido, o presente estudo teve como objetivo (i) investigar o impacto da empatia e do gênero como fatores moduladores do comportamento na tarefa Ultimatum Game (UG) na interação com uma pessoa de confiança (um amigo) e um desconhecido; (ii) investigar o comportamento caracterizado como punição altruísta no UG adaptado em dois contextos diferentes de interação (com ou sem custos pessoais envolvidos). Para isso, foi realizado 2 experimentos. O experimento 1, semelhante ao estudo anterior, os participantes jogaram o UG com o amigo e um desconhecido como os propositores. Mas com o controle de nível de empatia (alto e baixo) e gênero. No experimento 2, além do controle do gênero e do nível de empatia, os participantes tinham que decidir se aceitavam ou rejeitavam propostas de divisão de R$120,00 entre três pessoas: o propositor, o participante e um terceiro ( dummy ) que parte do jogo foi o amigo e outra parte do jogo um desconhecido, na primeira parte do jogo. Na segunda parte, os participantes apenas decidiam se aceitavam ou rejeitavam no lugar do amigo ou de desconhecidos não tendo ganhos e nem perdas envolvidos. Como resultados, foi observado maior taxa de rejeite de propostas injustas realizadas pelo desconhecido do que pelo amigo e estes foram julgados como mais justos. Também foi observado que homens rejeitaram mais propostas realizadas por um desconhecido e os participantes com alto nível de empatia rejeitaram mais propostas realizadas por um desconhecido. Em relação aos potenciais cognitivos, os participantes com alto nível de empatia apresentaram a amplitude do MFN mais negativa para o desconhecido e amplitude positiva para o amigo. Homens com alto nível de empatia apresentaram amplitude mais negativa do MFN para o desconhecido. Já no segundo experimento os participantes rejeitaram mais propostas injustas para ambos. A amplitude do MFN foi mais negativa quando as propostas foram injustas para ambos, assim como para as Mulheres e para as pessoas com alto nível de empatia. Na segunda parte do experimento 2 os participantes beneficiaram mais o amigo. A amplitude do MFN foi mais negativa para homens na interação desconhecido propondo para o amigo. As mulheres apresentaram maior amplitude do P300 na interação desconhecido propondo para o amigo. Tais resultados apontam para o impacto da empatia e do gênero quando o amigo está envolvido. Além disso, o envolvimento pessoal de ganhos e perdas também foi um fator importante na percepção de justiça. O presente estudo corrobora com estudos prévios de que a confiança modula a percepção de justiça e que a empatia e o gênero são fatores com maior ou menor impacto dependendo do contexto e do grau de confiança para com o outro.

Social attitude is the approach of a person displayed towards other individuals or groups. Social attitude comprehensively affects the way we perceive, behave in, and interact with, the surrounding world; it is simply not possible to understand complex social behaviour such as strategic thinking without first knowing the attitude of the parties involved. Several disciplines contribute to the complex study of social attitude (social preferences in economics, social value orientation in psychology), but only recently have these disciplines started to communicate and develop comprehensive definitions and models. In particular, the current research debate focuses on pinpointing the nature of social attitude (e.g., what its defining components are), the factors that influence it (e.g. context, other individuals), as well as its consequences (e.g., its relevance for self-image representation). This thesis aims to answer to some of the open questions in the literature by testing and comparing the proposed competing explanations. The studies presented are based on a series of behavioural experiments coupled with established but also newly developed measurement tools concerning social norms and personal preferences. In addition, we try to uncover the mental processes underlying decisions with the help of computational models. The thesis is structured as follows. In Chapter 1, We outline a brief summary of the theories on social attitude from the economic and psychological literature, and describe the main tasks and models employed in the thesis. Chapter 2 explores how social attitude is influenced by others’ behaviour. We conduct a systematic comparison of the possible mechanisms driving attitude conformity using various experimental conditions, computational models, and control tasks (e.g., norm elicitation). We find that participants conform due to both peer influence (by learning from others about how salient a norm is) and compliance to authority (i.e. experimenter demand effects). Chapter 3 studies the effect of context in a task eliciting social attitude. We specifically test the effect of unavailable choices, that we call ”meta-context”, on participant’s decisions. We find that participants’ concerns about social norms, as well as their choices, depend on the currently available options, but also on meta-context. In Chapter 4, we study whether individuals tend to selectively forget about their morally questionable choices, and information related to it, such as the context in which the choice was made. We find that participants recollect less correctly selfish or anti-social choices compared to pro-social ones, but we find no memory bias concerning the context of the choice. Moreover, we uncover some potential evidence of a second memory bias related to choice frequency: people are generally more pro-social than antisocial, which means antisocial choices are more rare and thus more difficult to remember correctly. Finally, in chapter 5 We summarise the main findings of the thesis and present some conclusions. We try to integrate the various results to propose an empirically-informed model of social attitude to be applied in future research on the topic.

Made available in DSpace on 2016-03-15T19:40:17Z (GMT). No. of bitstreams: 1 Gabriel Gaudencio do Rego.pdf: 1139897 bytes, checksum: b56f45681ad1b3adb1fbebc620c7562a (MD5) Previous issue date: 2014-08-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Games are useful tools to simulate social interactions of cooperation or competition and can be applied in conjunction with behavioral and electrophysiological techniques, such as Event Related Potentials (ERP) analysis. The Ultimatum Game (UG) is a well-studied game which can be used to investigate how individuals react to injustice. An initial value is divided between a proponent, who suggests a division rate of this value, and a respondent, who may accept or reject it. If the respondent accepts, both players gain the proposed value, and if he or she rejects, they gain nothing. The behavioral and electrophysiological results have demonstrated typical reactions in the game. The Medial Frontal Negativity (MFN), a component associated with the automatic processing of negative social feedback, and the P300, associated with attention and memory process, are two components commonly observed during UG. While the interaction between volunteers and proponents with typical development is well described, the interaction between volunteers and proponents with Down syndrome is still unknown. This research aimed to investigate differences in the behavioral data, MFN and P300 in participants playing the UG with a typical proposer and Down proposer. 32 subjects participated in the experiment. Scales of social desirability, moral identity, self-esteem and an implicit association test about Down syndrome were applied. The results showed similar behavioral patterns among proponents and previous data described in the literature. Regarding ERPs, the MFN was not detected and there was greater amplitude of P200 component for proposals of the Down. There was also greater amplitude of P300 for fair proposals of the typical proponent compared to the fair proposals of the Down, and of these two compared to unfair proposals of both. The amplitude of the P300 for proposals of typical was negatively correlated with self-esteem scores. Together, the results suggest that the presence of a player with Down syndrome might influence the perception and expectation of the participants about the game, and this effect could be extended to the interaction with the typical proponent. The absence of MFN suggests that participants do not perceived the unfair proposals as a social negative outcome and P300 suggests that the interaction with the typical proposer was more relevant to the participants. Moreover, this relevance was modulated due to personal characteristics of self-esteem. Further studies are suggested in this area to confirm the hypotheses suggested in the present research. / Os jogos simulam situações sociais relativamente simples de cooperação ou competição e podem ser aplicados conjuntamente às técnicas de pesquisa comportamentais e eletrofisiológicas como a análise de potenciais relacionados a eventos (ERP). Um jogo muito estudado é o Ultimatum Game (UG), que pode ser utilizado para investigar como indivíduos reagem à injustiça. Um valor inicial é dividido entre um propositor, que sugere uma divisão do valor, e um respondente que pode aceitar ou rejeitar. Caso este aceite os dois ganham o valor proposto, caso rejeite ninguém ganha. Os resultados comportamentais e eletrofisiológicos têm demonstrado reações comuns no jogo. Os ERPs mais comuns é o MFN, associado ao processamento automático de feedbacks sociais negativos, e o P300, associado a processos atencionais e de memorização. Enquanto a interação entre sujeitos de pesquisa com propositores de desenvolvimento típico já é bem conhecida, o efeito desta interação com propositores com síndrome de Down ainda é desconhecido. O presente buscou investigar diferenças no padrão comportamental, de MFN e P300 em participantes jogando UG com propositor típico e com Down. 32 sujeitos participaram do experimento. Foram aplicadas escalas de desejabilidade social, identidade moral, de autoestima e um teste de atitudes implícitas frente às pessoas com Down. Os resultados demonstraram padrões comportamentais semelhantes entres os propositores e a literatura. Quanto aos ERPs, o MFN não foi detectado e houve presença de componente P200 para propostas de Down. Houve também maior amplitude de P300 para propostas justas do típico em comparação as justas do Down e destes dois em comparação às propostas injustas de ambos. A amplitude do P300 para propostas do típico apresentaram correlação negativa com escalas de autoestima. Os resultados sugerem que a presença de um jogador com síndrome de Down influenciou a percepção e expectativa dos participantes quanto ao jogo, e que este efeito pode ter se estendido para a interação com o propositor típico. A ausência de MFN sugere que não houve processamento das propostas injustas como respostas sociais negativas e o P300 sugere que a interação com o propositor foi de maior relevância para os participantes. Além disto, esta relevância foi modulada em razão de características pessoais de autoestima. São sugeridos novos estudos no tema para confirmar as hipóteses aqui apresentadas.

Des difficultés sociales sont liées au trouble de la personnalité limite (TPL). Pour les comprendre, le traitement de l’information lors de décisions sociales doit être étudié. Parmi ces informations sociales, les expressions faciales émotives sont moins bien identifiées chez les individus ayant un TPL (Daros et al., 2013) comparativement aux individus sains. Également, une étude rapporte que des participants ayant un TPL acceptent plus d’offres monétaires, indépendamment du degré d’équité, que les individus sains dans une tâche de prise de décision sociale simulant des interactions avec des individus (représentés par des visages joyeux ou colériques) divisant de l’argent avec les participants (Polgár et al., 2014). Cependant, ils rapportent aussi que pour les offres monétaires de 20 à 30 % du montant à diviser les participants sains acceptaient les offres des visages joyeux plus fréquemment, cet effet était absent pour les participants ayant un TPL. L’objectif de cette étude est donc de savoir si les différences de reconnaissance des émotions médient la relation de la sévérité des traits du TPL avec des décisions sociales d’acceptation d’offres monétaires accompagnées d’expressions faciales (joie, colère et neutre). Nos résultats corroborent l’association négative des traits du TPL avec la reconnaissance des émotions (Daros et al., 2013) et l’association positive entre l’acceptation des offres et les traits du TPL (Polgár et al., 2014). Cependant, aucun effet médiateur n’est observé. Ainsi, nous concluons que la reconnaissance des émotions et la prise de décision sociale représentent des aspects indépendants des profils sociocognitifs liés aux traits du TPL. / Social difficulties are linked to borderline personality disorder (BPD). To understand them, the processing of information during social decisions must be studied. A form of social information is emotional facial expressions which are less well identified in individuals with BPD (Daros et al., 2013) compared to participants without a diagnosed mental health issue. Also, one study reports that participants with BPD accept more monetary offers (regardless of the amount of money they were offered) participants without a diagnosed mental health issue in a social decision-making task simulating interaction with individuals (represented by happy or angry faces) dividing money with participants (Polgár et al., 2014). However, they also report that for monetary offers that represented 20-30% of the divided sum, participants without a diagnosed mental health issue participants accepted offers from happy faces more frequently. However, this effect was absent in participants with BPD. The aim of this study is to determine whether differences in emotion recognition abilities mediate the relationship of BPD trait severity with social decisions to accept monetary offers accompanied by facial expressions (joy, anger and neutral). Our results support the negative association of BPD traits with emotion recognition (Daros et al., 2013) and the positive association between offer acceptance and BPD traits (Polgár et al., 2014). However, no mediating effect is observed. Thus, we conclude that emotion recognition and social decision-making represent independent aspects of the sociocognitive profiles related to BPD traits.

Das Konzept der interpersonellen Fähigkeiten bezieht sich auf Leistungsaufgaben der sozialen Kognition. Diese Aufgaben messen die Fähigkeiten Gesichter zu erkennen und sich diese zu merken sowie Emotionen zu erkennen und diese auszudrücken. Ziel dieser Dissertation war die Untersuchung des Einflusses von interpersonellen Fähigkeiten auf soziale Entscheidungen. Ein besonderer Fokus lag auf der Quantifizierung von individuellen Unterschieden in zugrundeliegenden neuronalen Mechanismen. Studie 1 erweiterte bestehende Evidenz zu Beziehungen zwischen psychometrischen Konstrukten der Gesichterkognition und Ereigniskorrelierten Potentialen, welche mit den verschiedenen Stadien der Gesichterverarbeitung (Enkodierung, Wahrnehmung, Gedächtnis) während einer Bekanntheitsentscheidung assoziiert sind. Unsere Ergebnisse bestätigen eine substantielle Beziehung zwischen der N170 Latenz und der Amplitude des frühen Wiederholungseffektes (ERE) mit drei Faktoren der Gesichterkognition. Je kürzer die N170 Latenz und je ausgeprägter die ERE Amplitude, umso genauer und schneller ist die Gesichterkognition. Studie 2 ergab, dass die Fähigkeit ängstliche Gesichter zu erkennen sowie die generelle spontane Expressivität während der sozialen Interaktion mit prosozialen Entscheidungen korreliert. Sensitivität für das Leid anderer sowie emotionale Expressivität scheinen reziproke Interaktionen mit Gleichgesinnten zu fördern. Studie 3 bestätigte das Modell der starken Reziprozität, da Prosozialität die negative Reziprozität im Ultimatum Spiel beeinflusste. Unter der Verwendung von Strukturgleichungsmodellen entdeckten wir, dass Menschen mit ausgeprägter Reziprozität eine größere Amplitude der relativen feedback-negativity auf das Gesicht von Spielpartnern zeigen. Insgesamt sprechen die Ergebnisse dafür, dass die etablierten individuellen Unterschiede in den Verhaltensmaßen der interpersonellen Fähigkeiten zum Teil auf individuelle Unterschiede in neuronalen Mechanismen zurückzuführen sind. / The concept of interpersonal abilities refers to performance measures of social cognition such as the abilities to perceive and remember faces and the abilities to recognize and express emotions. The aim of this dissertation was to examine the influence of interpersonal abilities on social decisions. A particular focus lay on the quantification of individual differences in brain-behavior relationships associated with processing interpersonally relevant stimuli. Study 1 added to existing evidence on brain-behavior relationships, specifically between psychometric constructs of face cognition and event-related potentials associated with different stages of face processing (encoding, perception, and memory) in a familiarity decision. Our findings confirm a substantial relationship between the N170 latency and the early-repetition effect (ERE) amplitude with three established face cognition ability factors. The shorter the N170 latency and the more pronounced the ERE amplitude, the better is the performance in face perception and memory and the faster is the speed of face cognition. Study 2 found that the ability to recognize fearful faces as well as the general spontaneous expressiveness during social interaction are linked to prosocial choices in several socio-economic games. Sensitivity to the distress of others and spontaneous expressiveness foster reciprocal interactions with prosocial others. Study 3 confirmed the model of strong reciprocity in that prosociality drives negative reciprocity in the ultimatum game. Using multilevel structural equation modeling in order to estimate brain-behavior relationships of fairness preferences, we found strong reciprocators to show more pronounced relative feedback-negativity amplitude in response to the faces of bargaining partners. Thus, the results of this dissertation suggest that established individual differences in behavioral measures of interpersonal ability are partly due to individual differences in brain mechanisms.