A Brain Mechanism Explains Why People Leave Certain Tasks for Later

"How does procrastination arise? The reason you decide to postpone household chores and spend your time browsing social media could be explained by the workings of a brain circuit. Recent research has identified a neural connection responsible for delaying the start of activities associated with unpleasant experiences, even when these activities offer a clear reward. The study, led by Ken-ichi Amemori, a neuroscientist at Kyoto University, aimed to analyze the brain mechanisms that reduce motivation to act when a task involves stress, punishment, or discomfort. To do this, the researchers designed an experiment with monkeys, a widely used model for understanding decisionmaking and motivation processes in the brain."

"In a later stage, the experimental design incorporated an unpleasant element. The monkeys were given the choice of drinking a moderate amount of water without negative consequences or drinking a larger amount on the condition of receiving a direct blast of air in the face. Although the reward was greater in the second option, it involved an uncomfortable experience. As the researchers anticipated, the macaques' motivation to complete the task and access the water decreased considerably when the aversive stimulus was introduced. This behavior allowed them to identify a brain circuit that acts as a brake on motivation in the face of anticipated adverse situations."

A neural connection between ventral striatum and ventral pallidum acts as a brake on motivation when actions predict stress, punishment, or discomfort. Two macaques trained on decision tasks chose between different liquid rewards to measure reward valuation. When a larger reward was paired with an aversive air blast to the face, willingness to perform the action dropped despite the higher payoff. Introducing the unpleasant stimulus significantly reduced task completion. The observed behavior linked activity in basal ganglia structures to delayed initiation of unpleasant-yet-rewarding actions, offering a mechanism for procrastination in aversive contexts.

Read at WIRED