Individuals with Adverse Childhood Experiences Explore Less and Underweight Positive Reward Feedback

Adverse Childhood Experiences (ACEs) are extreme stressors that lead to negative psychosocial outcomes in adulthood. Non-human animals explore less after exposure to early stress. Therefore, in this pre-registered study we hypothesised that reduced exploration following ACEs would also be evident in human adults. Further, we predicted that adults with ACEs, in a foraging task, would adopt a decision-making policy that relies on the most recent reward feedback, a rational strategy for unstable environments. We analysed data from 145 adult participants, 47 with four or more ACEs and 98 with fewer than four ACEs. In the foraging task, participants evaluated the trade-off between exploiting a known patch with diminishing rewards and exploring a novel one with a fresh distribution of rewards. Using computational modelling, we quantified the degree to which participants’ decisions weighted recent feedback. As predicted, participants with ACEs explored less. However, contrary to our hypothesis, they underweighted recent feedback. These unexpected findings might have occurred due to early adversity causing adults exposed to these experiences to use reward feedback less when making decisions. Our results may help to identify cognitive mechanisms that link childhood trauma to the onset of psychopathology.