|For men working together, stress plus coffee could be toxic|
The study involved 64 male and female participants (coffee drinkers at the University of Bristol with an average age of 22) completing various construction puzzles, negotiation and collaborative memory tasks in same-sex pairs. They did this after drinking decaffeinated coffee, which either had or hadn't been spiked covertly with caffeine (the equivalent of about three cups' worth of coffee). Stress was elevated for some of the pairs by telling them they would shortly have to give a public presentation, and by warning them that their participation fee would be performance dependent.
How large were the caffeine effects? The men's memory performance under stressful conditions with caffeine was described by the researchers as 'greatly impaired' whereas caffeine didn't affect women in the same situation. For the construction puzzles, caffeine under high stress conditions led men to take an average of twenty seconds longer (compared with no caffeine) whereas it led women to solve the puzzles 100 seconds faster.
A short-coming, acknowledged by the researchers, was that there were overall few effects of stress on the participants' performance, no doubt in part because they'd been told they could bail out any time they liked (although none of them did). Further research is clearly need to replicate the findings and explore the possible underlying mechanisms. Such work is urgent, the researchers concluded, 'because many ... meetings, including those at which military and other decisions of great import are made, are likely to be male-dominated. Our research suggests that men's effectiveness is particularly likely to be compromised. Because caffeine is the most widely consumed drug in the world, it follows that the global implications are potentially staggering.'
St. Claire, L., Hayward, R., and Rogers, P. (2010). Interactive Effects of Caffeine Consumption and Stressful Circumstances on Components of Stress: Caffeine Makes Men Less, But Women More Effective as Partners Under Stress. Journal of Applied Social Psychology, 40 (12), 3106-3129 DOI: 10.1111/j.1559-1816.2010.00693.x