Lindsay St. Claire and Peter J. Rogers, both of the University of Bristol in England, tested whether increased caffeine consumption exacerbates stress and disrupts team performance.
The researchers gave 64 men and women in same-sex pairs a range of tasks to complete, including carrying out negotiations, completing puzzles, memory tasks and high-pressure meetings. To add to the stress, each was told to deliver a public presentation.
The researchers gave decaffeinated coffees, half of which contained added caffeine, to the coffee drinkers.
The researchers measured individual cognitive appraisals, emotional feelings, bodily symptoms, coping, performance, memory, psychomotor performance, and negotiation skills under higher or lower stress conditions.
The study, published in the Journal of Applied Social Psychology, found women performed better and faster under stress, provided caffeine had been consumed, but the men were greatly impaired if they consumed the caffeinated coffee.