PhD defence

Computations in the Social Brain

• Michael Giffin

Date

Wednesday 26 May 2021

Time

15:00 - 15:45 hour

Address

Academy Building
Rapenburg 73
2311 GJ Leiden

Brief summary

This thesis consists of three empirical chapters that investigate elements of human social behavior through the combination of economic games, computational modeling, and neuroimaging. While each empirical chapter uses a different computational model applied to a different economic game, each chapter addresses a specific problem regarding human social living. In this way, each chapter contributes to a greater understanding of how humans are able to socially interact despite the incentives which repel individuals away from commonality.

Through the attacker-defender contest we show that when motives and abilities are asymmetrical such that one party (the attacker) can benefit at the expense of the other (the defender), attackers will utilize high-level recursive reasoning and associated neural circuitry in an attempt to profit at the expense of defenders. Through the trust game we show that reciprocity behavior falls in three simple categories, yet learning these categories occurs suboptimally through a combination of belief and experiential learning—with greater reliance on personal belief being associated with higher monetary outcomes. Through the ultimatum game we show that individuals can be nudged into exhibiting acceptability thresholds that resemble those of different cultures. Learning to adapt to these different “cultures” is impeded by social preferences, which in turn leads to false beliefs about the social environment.

Each study deals with a different collection of social norms and attempts to understand how humans reconcile the associated social dilemmas. Ultimately, each chapter acts as a building block contributing a different perspective to the study of human sociality. Using economic games, computational models based on the principle of utility, and model-based neuroimaging, my research contributes to the scientific endeavor working to crack the “elaborate and secret code that is written nowhere, known by none, and understood by all” (Sapir, 1927, p.137).

Supervisor

• Prof. C.K.W. de Dreu

PhD dissertations

PhD dissertations by Leiden PhD students are available digitally after the defence through the Leiden Repository, that offers free access to these PhD dissertations. Please note that in some cases a dissertation may be under embargo temporarily and access to its full-text version will only be granted later.

Press contact (only for journalists) 

Maarten Muns, Scientific Communications Adviser, Leiden University
[e-mail]
[phone]

Practical questions:

Pedel's office ([phone])

Long summary