Risk tolerance linked to amygdala and prefrontal cortex brain regions

How much risk are you willing to take, and does this change depending on the possible reward? 

New work published in the journal Neuron from Penn researchers Joseph Kable and Caryn Lerman reveals that brain structure and function, particularly with respect to the amygdala, the prefrontal cortex, and how the two are linked, influences a person’s inclination to engage in risky behaviors.  

“The more the amygdala and medial prefrontal cortex are functionally connected, the greater tolerance for risk individuals have,” says Kable, a psychologist who studies the neural mechanisms that affect decision-making. “In addition, more risk is associated with a larger amygdala. But a structural connection goes in the opposite direction; the fewer connections you have there, the more tolerant of risk you are.” 

For a clinical trial funded by the National Cancer Institute, Kable and Lerman, vice dean for strategic initiatives in Penn’s Perelman School of Medicine, recruited 108 healthy 18- to 35-year-olds to participate in a study focused on understanding why people act in ways detrimental to their health and whether it is feasible to positively shape such actions. 

Part of the trial comprised a single MRI imaging session that evaluated many different brain regions, called a multi-modal imaging assessment. The researchers also put participants through a rapid-fire decision-making exercise, asking them to choose between receiving a small-but-certain reward, $20, or a larger-but-tentative one, ranging from $21 to $85. The degree of chance for the latter scenario changed, hitting anywhere from 9 to 98 percent. Participants made more than 100 of these decisions to expose a clear picture of their overall risk-tolerance level. 

To ensure that the researchers were getting at true openness to risk, the contributors’ final decision had real financial consequences: Option 1, definitively leave with $20; Option 2, roll the metaphorical dice for the chance to receive a larger dollar value—or perhaps walk away with nothing at all. 

“Decision-making tendencies are a good indicator of someone’s tolerance for risk,” Kable explains, “whether he’s someone who is risk-averse and takes the safe option or risk-seeking and willing to take as much risk as we’ll give to get a higher payoff.” 

Lerman says these findings could have implications for many of the health-specific choices people make on a day-to-day basis, such as how much junk food they eat or whether to stop smoking. On a continuum from conservative to daredevil, those who fall closer to the latter, for example, are more likely to take up smoking and less likely to quit once they begin. 

There are also implications for mood disorders like attention deficit hyperactivity disorder and anxiety, as well as disorders of impulse control like gambling and addiction, she adds. “If you can characterize patterns of risk tolerance and the associated structural and functional neural markers, we could identify individuals who are most susceptible to these conditions and target preventive efforts accordingly.” 

The researchers say that there is still more to learn from these data and that future analyses could focus on situations with ambiguous or known negative outcomes unlike the current work, which looked only at scenarios with known positive outcomes. Nonetheless, they say the findings make sense from both a neuroscience and translational perspective and have the ability to positively affect many types of choices. 

“Risk plays such a large role in so many decisions, and it’s a feature of decision-making that has manifold effects throughout the lifespan,” Kable says. “It impacts teenagers deciding whether to be crazy when driving with their peers, people nearing retirement age trying to decide how much risk to take with their savings, and everyone in between.” 

Joseph Kable is the Baird Term Associate Professor of Psychology in the School of Arts and Sciences. 

Caryn Lerman is the vice dean for strategic initiatives and the John H. Glick Professor in Cancer Research at the Perelman School of Medicine. 

Funding for the research came from the National Cancer Institute’s Grant R01 CA170297.