Neuroscientists Decipher Procrastination: A Brain Mechanism Explains Why People Leave Certain Tasks for Later
How Procrastination Works arise? The reason you decide to put off household chores and spend your time browsing social media could be explained by how a brain circuit works. Recent research has identified a neural connection responsible for delaying the onset of activities associated with unpleasant experiences, even when those activities offer an obvious 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 decision-making and motivation processes in the brain.
The scientists worked with two macaques trained to perform various decision-making tasks. In the first phase of the experiment, after a period of water restriction, the animals could activate one of two levers that released different amounts of fluid; one option offered a smaller reward and the other a larger one. This exercise allowed them to evaluate how the value of the reward influences the willingness to perform an action.
Later, the experimental design incorporated an unpleasant element. The monkeys had the choice of drinking a moderate amount of water without negative consequences or drinking a larger amount provided they received 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 predicted, the macaques’ motivation to complete the task and access the water decreased significantly 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. In particular, the connection between the ventral striatum and the ventral pallidum, two structures located in the basal ganglia of the brain, known for their role in the regulation of pleasure, motivation and reward systems, was observed.
Neural analysis revealed that when the brain anticipates an unpleasant event or potential punishment, the ventral striatum is activated and sends an inhibitory signal to the ventral pallidum, which is normally responsible for the intention to perform an action. In other words, this communication reduces the impulse to act when the task is associated with a negative experience.
The brain connection behind procrastination
To study the specific role of this connection, as described in the study published in the journal Current Biology, the researchers used a chemogenetic technique which, through the administration of a specialized drug, temporarily disrupted the communication between the two regions of the brain. In doing so, the monkeys regained the motivation to undertake tasks, even in tests involving blowing air.
Notably, the inhibitory substance produced no change in trials where reward was not accompanied by punishment. This result suggests that the EV-PV circuit does not regulate motivation generally, but rather is specifically activated to suppress it when there is an expectation of discomfort. In this sense, apathy towards unpleasant tasks seems to develop gradually as communication between these two regions intensifies.
Beyond explaining why people tend to unconsciously resist uncomfortable household chores or obligations, the findings have relevant implications for understanding disorders such as depression or schizophrenia, in which patients often experience a significant loss of the will to act.
However, Amemori emphasizes that this circuit serves an essential protective function. “Overwork is very dangerous. This circuit protects us from burnout,” he said in comments reported by Nature. Therefore, he cautions that any attempts to externally modify this neural mechanism must be approached with caution, as further research is needed to avoid interfering with the brain’s natural protective processes.
This story originally appeared in WIRED in Spanish and has been translated from Spanish.
