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Paper accepted: modeling pavlovian control in escape versus avoidance

Posted 31/10/2017

Just-accepted paper in Journal of Cognitive Neuroscience as the fruits of a fun collaboration with Alex Millner, Matthew Nock and Sam Gershman @ Harvard University. Read the abstract below, or check out data and analysis code at the Alex’s Open Science Framework webpage (

To survive in complex environments, animals need to have mechanisms to select effective actions quickly, with minimal computational costs. As perhaps the computationally most parsimonious of these systems, Pavlovian control accomplishes this by hardwiring specific, stereotyped responses to certain classes of stimuli. It is well-documented that appetitive cues initiate a Pavlovian bias towards vigorous approach; however, Pavlovian responses to aversive stimuli are less well understood. Gaining a deeper understanding of aversive Pavlovian responses, such as active avoidance, is important given the critical role these behaviors play in several psychiatric conditions. The goal of the current study was to establish a behavioral and computational framework to examine aversive Pavlovian responses (activation vs. inhibition) depending on the proximity of an aversive state (escape vs. avoidance). We introduce a novel task in which subjects are exposed to primary aversive (noise) stimuli, and characterized behavior using a novel generative computational model. This model combines reinforcement learning and drift-diffusion models, so as to capture effects of invigoration/inhibition in both explicit choice behavior as well as changes in reaction time. Choice and reaction time results both suggest that escape is associated with a bias for vigorous action whereas avoidance is associated with behavioral inhibition. These results lay a foundation for future work that promise to provide insights into typical and atypical aversive Pavlovian responses involved in psychiatric disorders, allowing us to quantify both implicit and explicit indices of vigorous choice behavior in the context of aversion.