A study published on March 21 in the Proceedings of the National Academy of Sciences found that taking risks is contagious. People are more likely to commit risky behaviours when observing somebody else doing it.

The researchers from Caltech recruited 24 individuals for their experiment involving three trials, namely the “Self” trial, the “Observe” trial, and the “Predict” trial. For the “self” trial, the participants had to choose between 10 dollars (AU$ 13.17) and gambling for a higher payoff. In the observed trial, they needed to watch closely the risk-taking behaviours of other people and in the predict trial, they needed to predict another person’s risk-taking behaviour correctly to earn cash.

The team found that individuals were more likely to take risky actions after observing someone else taking risky actions or as they call it, the contagion effect. When these participants observed non-risky behaviours, they would also avoid taking risks. Moreover, the observers learned to predict the risk-taking behaviours of another person.


This image shows a region of the brain called caudate nucleus responding to the degree of risk in the gamble. Credit: J. O’Doherty Laboratory/Caltech

The functional magnetic resonance imaging or fMRI results indicate that the brain part called caudate nucleus activates during risk-taking tendencies. Another brain part called the dorsolateral prefrontal cortex or dIPFC was activated when these participants were observing others do risky behaviours.

The research team then concludes that these two brain regions work together to make one more or less prone to taking risks. These findings can also be observed in financial markets where one may make or avoid risky investments because another made the choice despite not knowing the consequences.

“The findings reported in this paper are part of a broader research goal at Caltech, in which we are trying to understand how the brain can learn from other people and make decisions in a social context,” concludes lead researcher John O’Doherty, a professor of psychology and director at Caltech Brain Imaging Centre. “Ultimately, if we can understand how our brains function in social situations, this should also enable us to better understand how brain circuits can go awry, shedding light on social anxiety, autism, and other social disorders.”