A recent study has revealed why introverts and extroverts process experiences differently and found that extroverts associate their environment with dopamine.
Frontiers in Human Neuroscience published the study. In it, a group of 70 people from Cornell were given personality tests that determined whether they were extroverted or introverted.
During a double-blind procedure, some subjects took Ritalin and watched videos in the lab.
Neurobiologists Yu Fu and Richard Depue then had the participants take a test to determine how strongly they associated the videos and lab environment with the rush of dopamine that Ritalin produced.
They found that Ritalin translated to reward or motivation for extroverts, while introverts did not show an association.
This was because introverts did not associate their environment with reward while extroverts did.
The researchers speculate this is because brains of introverts weigh internal cues more heavily than external motivational and reward cues.
Charles Carver, a psychologist at the University of Miami, said the findings are enlightening.
"The findings help link the personality trait of extraversion to a particular set of processes in the nervous system," he said. "The effect obtained was a very subtle one, because it turned on the involuntary occurrence of conditioning among some people but not others."