Neuroscientists Explain Procrastination: A Brain Mechanism Explains Why People Leave Certain Tasks Later

How to undo it wake up? The reason you decide to put off household chores and spend your time browsing social media can be explained by the functioning of brain circuits. Recent research has identified a neural connection responsible for delaying the onset of activities associated with unpleasant experiences, even when these activities provide a clear reward.

The study, led by Ken-ichi Amemori, a neuroscientist at Kyoto University, aims to analyze brain mechanisms that reduce motivation to act when a task involves stress, punishment, or discomfort. To do this, the researchers designed experiments with monkeys, a widely used model for understanding decision-making and motivational processes in the brain.

The scientists worked with two macaques trained to perform different decision-making tasks. In the first phase of the test, after a certain period of water restriction, the animals can open one of two levers that release different amounts of liquid; one option offers a small reward and the other a large one. This experiment allowed them to examine how the value of the reward influences the willingness to perform an action.

In the next phase, the experimental design included a negative factor. The monkeys were given the choice to drink a moderate amount of water without side effects or to drink a large amount in the condition of receiving a direct air blast to the face. Although the reward was greater for the second choice, it involved an uncomfortable experience.

As the researchers expected, the macaques’ motivation to complete the task and reach for the water decreased significantly when an aversive stimulus was presented. This behavior allowed them to identify a brain circuit that acts as a brake on motivation when faced with negative expectations. In particular, connections between the ventral striatum and the ventral pallidum, two structures located in the basal ganglia of the brain, known for their role in regulating pleasure, motivation, and reward systems, were found to be involved.

Neural analysis revealed that when the brain anticipates an unpleasant event or possible punishment, the ventral striatum is activated and sends an inhibitory signal to the ventral pallidum, which is often responsible for driving the intention to act. In other words, this interaction reduces the impulse to act when the task is associated with a negative experience.

The Brain Connection Behind Procrastination

In order to investigate the specific role of this connection, as described in a study published in the journal Current Biology, researchers used a chemogenetic method, through the administration of a special drug, temporarily disrupted the communication between the two regions of the brain. By doing so, the monkeys regained motivation to initiate tasks, even in those experiments that involved blowing air.

Notably, the inhibitory factor did not produce a change in trials in which the reward did not match the punishment. This result suggests that the EV-PV circuit does not regulate motivation in a general way, but rather is specifically activated to suppress when there is an expectation of discomfort. In this sense, indifference to undesirable activities seems to gradually increase as the connection between these two regions increases.

Apart from explaining why people often unconsciously refuse to start household chores or uncomfortable obligations, the findings have relevant implications for the understanding of disorders such as depression or schizophrenia, where patients tend to have a severe loss of the will to take action.

However, Amemori emphasizes that this region serves an important protective function. “Overworking is very dangerous. This region protects us from fatigue,” he said in a statement reported by Nature. Therefore, he warns that any attempt to change this neural process outside should be approached carefully, as more research is needed to avoid interfering with the brain’s natural defense mechanisms.

This story appeared on WIRED en Español and has been translated from Spanish.