High stakes slow responding, but do not help overcome Pavlovian biases in humans

Abstract

Abstract“Pavlovian” or “motivational” biases are the phenomenon that the valence of prospective outcomes modulates action invigoration: Reward prospect invigorates action, while punishment prospect suppresses it. While effects of the valence of prospective outcomes are well established, it is unclear how the magnitude of outcomes modulates these biases. In this pre-registered study (N= 55), we manipulated stake magnitude (high vs. low) in an orthogonalized Motivational Go/ NoGo Task. We tested whether higher stakes (a) strengthen biases or (b) elicit cognitive control recruitment, enhancing the suppression of biases in motivationally incongruent conditions. Confirmatory tests yielded that high stakes slowed down responses independently of the Pavlovian biases, especially in motivationally incongruent conditions, without affecting response selection. Reinforcement-learning drift-diffusion models (RL-DDMs) fit to the data suggested that this effect was best captured by stakes prolonging the non-decision time, but not affecting the response threshold as in typical speed-accuracy tradeoffs. In sum, these results suggest that high stakes result in a slowing-down of the decision process without affecting the expression of Pavlovian biases in behavior. We speculate that this slowing under high stakes might reflect heightened cognitive control, which is however ineffectively used, or reflect positive conditioned suppression, i.e., the suppression of locomotion by high-value immanent rewards, as phenomenon previously observed in rodents that might also exist in humans. Pavlovian biases and slowing under high stakes seem to arise in parallel to each other.