Acute stress prompts riskier decisions in young men

There is evidence that acute stress impacts decision making (DM) under risk. It has been concluded that stress prompts riskier decisions in men. However, in the DM tasks used thus far, the expected value (EV) of reward and risk of decision options are confounded and it is, therefore, unclear which component is being affected by acute stress.We developed a new DM paradigm, in which EV of reward and risk of decision options are independent and quantifiable. Subjects (5 men, age: 31.2 ±1.92 years) completed 220 trials in which they had to repeatedly choose between a safe and a risky option associated with different EV of reward and risk. Stress was induced using the Socially Evaluated Cold Pressor Test (SECPT). Each subject received the SECPT and the corresponding control condition in random order.Comparing the stress and control condition on a trial-by-trial basis, we found that, descriptively, gamble variance, a measure for the risk associated with decision options, was about 10% higher when subjects were stressed compared with when they received the control manipulation. EV of reward on which subjects gambled did not differ between stress and control manipulation.Our data provide a first hint that risk but not reward processing in healthy young men might be affected by acute stress