The Cognitive cost of interpersonal closeness in decision making

Uğurlar, Nesibe Pınar
Prior research has consistently demonstrated that prosocial behavior, cooperation, and trust increase with interpersonal closeness. This dissertation suggests a cognitive computational cost as an explanation for prosocial preferences driven by interpersonal closeness. Current hypothesis is based on the inclusion of other in the self approach suggesting that the overlap between the mental representations of the self and the other increases by closeness, which, in turn, makes it difficult to differentiate between the self-concept and the close other. I argue that people require a distinct and separate self-concept in order to process any self-related information during a decision making process, and closeness interferes with retrieving the self-concept from memory. Based on these assumptions, closeness is expected to interfere with the cognitive processing of information. The decision making process should be more cognitively demanding when the decision incorporates information cues related with both the self and the close other. The studies of this dissertation were, thus, concerned with the cognitive performance during decision making. Time taken to complete decision tasks, response accuracy, and self-reported task difficulty were measured in decision tasks. In eleven experiments and one correlational study, I tested how the cognitive performance during interpersonal economic exchange decisions differs depending on the closeness to the given interaction partner. Five of the studies supported the hypothesis that closeness indeed impairs cognitive performance. The findings are the first to demonstrate how interpersonal decision processes are not only motivationally driven but also driven by a cognitive computational cost resulting from the self-other overlap.