Active Sampling and Sex Differences in Perceptual Decision Making in Rats

Decisions are typically viewed as arising from a sequential process: perception, decision, and then action. However, an alternative perspective, drawing from ecological psychology and embodied cognition, suggests that perception, decision, and action are interconnected in a cycle. Perception is an active process where information is gathered from the environment through actions that sample task stimuli. The sampling behavior of an animal reflects its internal state and serves as inputs that influence the decision-making process. To examine this framework, we trained rats on a visual stimulus detection task with three luminance levels. Our findings indicated that the time rats spent actively sampling the stimuli correlated with their success in detection, regardless of the cue’s luminance. Drift Diffusion Models (DDMs) showed that cue luminance primarily affected the rate of evidence accumulation (drift rate), while active sampling specifically influenced the decision threshold. These results suggest that perceptual decisions are reliant on active cue sampling, supporting the notion that actions and decisions are co-regulated. We also identified significant sex differences: female rats spent more time sampling the cues than male rats. Additionally, males took longer to act after making errors, possibly due to less efficient sampling behavior. These performance differences were linked to negative influences of sampling time on drift rates in females, but not in males. This divergence in the relationship between active sampling and DDM parameters is further support for a sex difference in choice impulsivity.