Daredevils take risks because they can't help it, according to new research on brain anatomy.
A new study on brain structure revealed that risk takers have different brains than their more conservative counterparts.
Researchers from Yale University discovered that people who seek out stimulation and act impulsively have substantially less gray matter in brain regions involved with decision making and self-control.
Lead researcher Avram Holmes said that the latest findings support previous studies linking brain anatomy with impulsivity, sensation-seeking behavior and substance abuse.
"The findings allow us to have a better understanding of how normal variation in brain anatomy in the general population might bias both temperamental characteristics and health behaviors, including substance abuse," said Holmes, an assistant professor of psychology and psychiatry at Yale University.
The latest study, which involved brain structure data from 1,234 participants between the ages of 18 and 35. Researchers noted that none of the participants in the study suffered psychiatric disorders or substance abuse.
Participants were asked to undergo brain scans using magnetic resonance imaging and answer questionnaires assessing levels of their impulsivity and sensation-seeking. They were also asked to report their alcohol, tobacco and caffeine consumption.
After comparing brain scans to answers from questionnaires, researchers found distinct differences in the brain structures of participants who reported high impulsivity and sensation-seeking.
Further analysis revealed that participants who reported high impulsivity or sensation-seeking had significantly thinner cortices, the gray wrinkly outer layer of the brain, in brain regions linked to decision making and self-control. Furthermore, cortical thickness was particularly reduced in the brain's anterior cingulate and middle frontal gyrus associated with emotion and behavior regulation.
"Our tendency to engage in sensation-seeking and impulsive behaviors evolved as a function of their influence on survival and reproductive fitness. They are not simply synonymous with adverse outcomes. For instance, sensation seeking co-varies with social behavior, social support, physical activity, reproductive opportunities and environmental exploration. There is likely no universally optimal temperament," Holmes told Live Science.
Experts said the findings are important because it shows that substance abuse can't always explain differences in brain anatomy.
"A strength of the study is that they identify this relationship within non-substance using participants, implying that these variations are not merely the consequence of individual history of substance use," noted Kristine Beate Walhovd, a professor of neuropsychology at the University of Oslo in Norway who was not involved with the study.
The findings are published in the Journal of Neuroscience.
