Gender differences in response latency in the two-armed bandit

Abstract

Decision making is a function that is integral to our survival yet impaired in neuropsychiatric disease. In addition, some of the most common neuropsychiatric disorders, including depression and anxiety, show a clear gender bias in rate of diagnosis. Thus, clarifying the fundamental gender differences in decision making may help explain the difference in risk between men and women for neuropsychiatric conditions. One feature of decision making that has not been well examined in terms of gender differences is response time (RT). As RT has previously been shown to systematically change in response to the outcome (reward vs. no reward) of the previous trial, we developed an experiment to further investigate the presence of outcome-dependent latency modulation in male and female human subjects. In this study, we analyzed choice and RT data from 198 subjects (81 females, 117 males) who were tested with the two-armed bandit, a popular probabilistic learning task. We found that while both genders learned the task and showed classical win-stay/lose-switch behavior, males were significantly faster than females to initiate trials and choose between the two presented options. Contrary to our expectations, RT modulation by previous trial outcome was not observed in either gender; however, there was RT modulation by relative chosen value, consistent with data from mice. Furthermore, age was a good predictor of RT at both initiation and choice in males, but not in females. In sum, we report that males and females demonstrate basal differences in RT that are differentially affected by age, and we replicate our findings from mice by showing that both genders (but especially females) are slower to initiate trials where they will choose the lower-value option.