"It has been known for some time that intelligence and self-control are related, but we didn't know why. Our study implicates the function of a specific brain structure, the anterior prefrontal cortex, which is one of the last brain structures to fully mature," said psychologist Dr. Noah A. Shamosh, who conducted the study with Jeremy R. Gray.
During the study, the researchers presented 103 healthy adults with a delay discounting task to assess self-control: a series of hypothetical choices where they had to choose between two financial rewards.
While the subjects could get the smaller financial reward immediately, the larger reward could be received at a later time.
The participants then underwent a variety of tests of intelligence and short term memory.
On another day, subjects' brain activity was measured using fMRI, while they performed additional short-term memory tasks.
The researchers found that the participants with the greatest activation in the anterior prefrontal cortex scored the highest on intelligence tests, and exhibited the best self-control during the financial reward test.
Writing about the finding in the Association for Psychological Science, the researchers said that the anterior prefrontal cortex was the only brain region to show that relation.
According to the researchers, greater activity in the anterior prefrontal cortex helps people not only to manage complex problems, resulting in higher intelligence, but also aids in dealing with simultaneous goals, leading to better self-control.
They say that the knowledge of the neural mechanisms underlying the relationship between short term memory, intelligence and delay discounting may result in improved techniques of increasing self-control, something that is particularly applicable in regulating behavior related to gambling and substance abuse.
"Understanding the factors that support better self-control is relevant to a host of important behaviors, ranging from saving for retirement to maintaining physical and mental health," the authors conclude.