Year: 2025
Type: dissertation
Abstract: The overarching aim of this dissertation was to elucidate the computational and neural mechanisms underlying approach-avoidance conflict resolution in social and non-social contexts, with a particular focus on the potential of financial incentives to reduce avoidance biases. The first project explored how financial incentives modulate pre-existing social biases, specifically the tendency to approach ingroup members and avoid outgroup members. Using a newly developed social approach-avoidance learning task, participants’ trial-by-trial behavior was assessed to investigate how financial incentives might reduce these biases. The results of our linear mixed models analyses replicate a pre-existing ingroup approach bias that is reduced by learning experiences in which outgroup approach was rewarded by financial incentives. Results from a Bayesian mixed model analysis, however, show that the underlying impressions towards the social groups remained unchanged. Computational modeling revealed that learning in social contexts is best explained by models that differentiate between positive and negative feedback, whereas learning in non-social contexts can be captured by a simpler model. These results highlight the capacity of non-social rewards to influence social behavior without affecting the underlying attitudes. The second project investigated how financial incentives affect avoidance of pain and the neural substrates involved, particularly focusing on the midbrain periaqueductal gray (PAG), a region which has been associated with conflict resolution in rodent studies. Participants performed another newly developed approach-avoidance conflict task involving potentially simultaneous prospects of appetitive monetary rewards and risk of aversive painful stimulation, while we were measuring their brain activity using ultra-high field (7T) functional magnetic resonance imaging. The results showed that higher probabilities of both reward and pain increased response times, reflecting increased conflict. On the neural level, the results of our parametric modulation analyses revealed that the dorsomedial PAG was specifically engaged during approach decisions made despite increasing risk of pain compared to avoidance decisions made despite increasing probability for money. Providing translational evidence, these results suggest that the PAG brain stem circuits established in rodents play an important role in conflict resolution in the human brain as well. Together, these projects demonstrate that financial incentives can significantly shape approachavoidance conflict resolution in social and non-social domains. Moreover, this dissertation provides novel evidence that brainstem circuits, particularly the PAG, play a crucial role in mediating these processes in humans, extending insights from animal models to human neurobiology.
DOI: 10.25972/opus-43072
Author: Bischofberger, Jasper Amadeus
Language: English
Subfield: Cognitive Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
Funder: Deutsche Forschungsgemeinschaft
OpenAlex ID: W7105988511