A little guy and a big guy walk into a bar. After a few drinks, which one is more likely to start a fight?
New research suggests it's the big guy.
In "The big, the bad and the boozed-up: Weight moderates the effect of alcohol on aggression," C. Nathan DeWall, Brad J. Bushman, Peter R. Giancola and Gregory D. Webster write that heavy men are more likely to be aggressive under the influence of alcohol than men who weigh less than them. They believe their findings, to be published in the July 2010 issue of the Journal of Experimental Social Psychology, provide some support for the "big, drunk, aggressive guy" stereotype (one that, we're guessing, the researchers haven't been on the receiving end of).
Previous research has found that, alcohol aside, larger, heavier males are more aggressive than their smaller, lighter counterparts; this is true not only for humans, but for insects, fish and other mammals. For women, on the other hand, there appears to be no relationship between body size and aggression.
The authors cite the recalibrational theory of anger as one reason why body size predicts aggression for guys but not girls. This theory posits that individuals with more "social bargaining power" are more anger-prone, feel more entitled to be treated well and are more likely to prevail in conflicts of interest. For men, strength increases social bargaining power; for women, physical attractiveness does.
The team also makes the case that weight is linked to importance in semantic memory. This suggests that greater weight would give a guy a greater sense of self-importance, therefore making him more likely to retaliate if provoked.
The researchers predicted that alcohol would increase aggression for "big guys" because it reduces their social inhibitions when they are provoked. To test their hypothesis, they recruited 543 social drinkers (276 men) aged 21 to 35. After they were weighed, the participants were given 20 minutes to drink either an alcoholic beverage or a placebo drink they were told was alcoholic. Those with alcohol got a dose of 1 g/kg of 95 percent alcohol mixed at a 1:5 ratio with orange juice (i.e., a screwdriver), and those drinking the placebo drink had the same amount of orange juice mixed with only 4 ml of alcohol. For good measure, the scientists added 4 ml of alcohol on top of the juice in the placebo drink and sprayed the rims of the placebo glasses with alcohol to keep the control group members in the dark.
Study participants then competed with fictitious same-sex opponents in a reaction-time task. The winners delivered electric shocks to the losers, and for each trial, participants chose the intensity and duration of the shocks their opponents would receive if they lost.
The study consisted of two blocks of 16 trials, with two "transition" trials between each block. Participants won half the trials and lost half; they received relatively low shock intensities during their first eight losses and relatively high shock intensities during the second eight. They got moderate-intensity shocks during the transition trials, so that the experiment would roughly replicate the escalation of violence in a real-life scenario.
The alcohol group members had breath alcohol concentrations of approximately 0.09 percent when they began the trials; the placebo group started the trials about two minutes after drinking their beverages (presumably to minimize the effects of the minimal amount of alcohol in their drinks).
The researchers found that alcohol, compared to placebo, increased aggression among the heavier men but had little effect on the lighter men. They replicated the first experiment using 327 new subjects, 162 of them men, with similar results.
Although they readily admit their study's limitations (they only used one measurement of physical size and only measured weight at one point in time), the authors conclude that weight increases the probability that a drunk guy will get aggressive.
Weight did not, however, increase the likelihood that an intoxicated woman will get aggressive. But the team found that alcohol does increase aggression in women overall, and if the recalibrational theory of anger holds true, physical attractiveness increases aggression in women who have been drinking.
So watch out, bar flies — when it's close to closing time the hottest girl in the room could be just as likely to get in a fight as her bigger-than-you boyfriend.