University study links dopamine levels with learning and motivation

Wednesday, December 2, 2015 - 3:12pm

Students can sometimes lose motivation heading into final exams, and the answer as to why may lie within dopamine, University researchers found in a study.

Psychology Prof. Joshua Berke, one of the study’s authors, and Arif Hamid, a neuroscience doctoral student and lead author of the study, point to a link between dopamine, a reward chemical in the brain, and learning and motivation.

The study, released last week, found that dopamine levels in the brain communicate the value of particular tasks. Berke said these value signals then allows people to determine how much effort they should put toward a goal. Those judgements are based on an evaluation of the potential rewards from completing the task and the consequences of either avoiding the test or failing to complete it successfully. If dopamine levels communicate that a task is worthwhile, the individual will likely feel more motivated to tackle it.

“You’re less likely to be distracted because this activity that you’re engaged in is considered to be more worthwhile,” he said. “That is not previously accounted for by our theories of dopamine function, and now it is.”

The research was conducted by measuring dopamine levels in rats. The rats were observed while they performed decision-making tasks, like choosing a door, then rewarded for choosing the correct door. When the rats had been rewarded, they began to decide faster, indicating increased motivation. They also were more likely to choose the option that had previously rewarded them, showing increased learning.

Elevated dopamine levels corresponded with both motivation and learning in the rats. This finding is novel: Previously, researchers considered it counterintuitive that a neurotransmitter such as dopamine could achieve both motivating and learning functions. In other words, dopamine could contribute either to motivation or to learning, but not to both.

Though many researchers have attempted to resolve this dynamic, Berke said this new study represents a major stride toward doing just that.

“All the theoretical ideas had been about learning, but so much of the observations about how drugs affect people and so forth have really been about motivation and not about learning,” Berke said.

Additionally, the team looked at the effect of artificially spiking dopamine levels in rats. They found that this spike also correlated with increased motivation and learning.

Hamid said this finding has implications in humans, as it explains why ADHD drugs such as Ritalin or Adderall — which are known to increase the brain’s dopamine levels — help people focus better. They affect brain chemistry to create an increase in the seeming value of activities, as well as facilitate quicker learning.

“Now we can more closely understand the relationship between how to be motivated to learn,” Hamid said.