The ability to decide quickly is partly determined by the strength of the fibres that connect two areas of the brain. These are the findings of a study by University of Amsterdam (UvA) neuroscientist Birte Forstmann and methodologist Eric-Jan Wagenmakers. What makes this study special is the discovery that individual differences in strategic decision-making behaviour can be traced to individual differences in brain connectivity. The results were recently published in the scientific journal Proceedings of the National Academy of Sciences (PNAS).
Quick decisions generally have a greater chance of error than decisions requiring more time. It is therefore important, for both humans and animals, to be able to switch flexibly between decision-making behaviour that is virtually error-free (but slow) to decision-making behaviour that is quick (but risky). Little is yet known about this switching ability
Forstmann and Wagenmakers conducted the research with British, German and Australian colleagues. In the first study, an MRI scanner was used to measure the strength of the connections between the pre-SMA (part of the cortex, on the outside of the brain) and the striatum (an area deep within the brain) of nine people. The participants then had to make a series of simple decisions, either under instruction not to make mistakes, or under instruction to be quick.
Brain 'Highways'Participants with a strong connection between areas of the brain were better able to switch flexibly from quick but risky decision-making to safe but slow decision-making. The researchers found the same result in a second study with twelve people.
Strong neural connections are like a wide five-lane highway, making it easier to switch between fast and slow decision-making, in contrast to a one lane, unpaved road between two areas of the brain. Forstmann and Wagenmakers' research suggests there is a specific mechanism in the brain that enables people to find a balance between the conflicting interests of rapid response and correct response.