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September 01, 2011

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Intoxicated: you know your mistakes, but don’t care, study finds

Sept. 1, 2011
Courtesy of the University of Missouri-Columbia
and World Science staff

Most of us have seen smart peo­ple do­ing dumb or em­bar­rass­ing things when drunk. But what ex­actly hap­pens in the brain to cause this? A new study has found that al­co­hol dulls the brain “sig­nal” that warns peo­ple when they’re mak­ing a mis­take, so that they still real­ize it—but don’t care as much.

“When peo­ple make mis­takes, ac­ti­vity in a part of the brain re­spon­si­ble for mon­i­tor­ing be­hav­ior in­creases, es­sen­tially send­ing an alarm sig­nal to oth­er parts of the brain in­di­cat­ing that some­thing went wrong,” said psy­chol­o­gist Bruce Bartholow of the Uni­vers­ity of Mis­souri. “Our study is­n’t the first to show that al­co­hol re­duces this alarm sig­nal, but con­tra­ry to pre­vi­ous stud­ies, our study shows that al­co­hol does­n’t re­duce your aware­ness of mis­takes – it re­duces how much you care about” them.

Bartholow and colleagues meas­ured the brain ac­ti­vity of 67 par­ti­ci­pants, ages 21-35, as they com­plet­ed a chal­leng­ing com­put­er task de­signed to elic­it some er­rors. About one third of the par­ti­ci­pants were giv­en al­co­holic drinks, while the rest re­ceived an al­co­hol-free drink or noth­ing. In ad­di­tion to mon­i­tor­ing their brain ac­ti­vity, the re­search­ers al­so meas­ured changes in par­ti­ci­pants’ mood and their ac­cu­ra­cy both real and per­ceived in the task.

In those who had con­sumed al­co­hol, the brain’s “a­larm sig­nal” in re­sponse to er­rors was found to be much less pro­nounced; the drinkers were al­so less likely to re­act by slow­ing down to be more care­ful. But they were no less likely to real­ize when they had made a mis­take.

“It is very com­mon for peo­ple to re­spond more slowly fol­low­ing an er­ror, as a way of try­ing to re­gain self-con­trol. That’s what we saw in our [al­co­hol-free] group. The al­co­hol group par­ti­ci­pants did­n’t do this,” Bartholow said.

The re­search­ers al­so found that the size of the brain’s alarm sig­nal was strongly as­so­ci­at­ed with par­ti­ci­pants’ mood at the time of the test, and that most of the par­ti­ci­pants in the al­co­hol group re­ported feel­ing “less nega­tive” af­ter drink­ing than be­fore.

“There are cer­tain cir­cum­stances un­der which re­duc­ing the brain’s alarm sig­nal could be seen as a good thing, be­cause some peo­ple, like those with anx­i­e­ty dis­or­ders, are hyper-sensitive to things go­ing wrong. In some peo­ple, a small amount of al­co­hol can take the edge off those anx­ious feel­ings, but con­sist­ently drink­ing as a way to re­duce anx­i­e­ty can lead to se­ri­ous prob­lems, in­clud­ing al­co­holism,” said Bartholow. “Gen­erally speak­ing, hav­ing a strong brain re­sponse to mis­takes pro­motes bet­ter self-con­trol and helps peo­ple avoid mak­ing fur­ther mis­takes in the fu­ture.”

The study is to be pub­lished in the Jour­nal of Ab­nor­mal Psy­chol­o­gy.

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Most of us have seen smart people doing dumb or embarrassing things when drunk. But what exactly happens in the brain to cause this? A new study has found that alcohol dulls the brain “signal” that warns people when they’re making a mistake, so that they still realize it—but don’t care as much. “When people make mistakes, activity in a part of the brain responsible for monitoring behavior increases, essentially sending an alarm signal to other parts of the brain indicating that something went wrong,” said psychologist Bruce Bartholow of the University of Missouri. “Our study isn’t the first to show that alcohol reduces this alarm signal, but contrary to previous studies, our study shows that alcohol doesn’t reduce your awareness of mistakes – it reduces how much you care about making those mistakes.” Bartholow’s team measured the brain activity of 67 participants, ages 21-35, as they completed a challenging computer task designed to elicit some errors. About one third of the participants were given alcoholic drinks, while the rest received an alcohol-free drink or nothing. In addition to monitoring their brain activity, the researchers also measured changes in participants’ mood, their accuracy in the computer task, as well as their perceived accuracy. In those who had consumed alcohol, the brain’s “alarm signal” in response to errors was found to be much less pronounced; the drinkers were also less likely to react by slowing down to be more careful. But they were no less likely to realize when they had made a mistake. “It is very common for people to respond more slowly following an error, as a way of trying to regain self-control. That’s what we saw in our [alcohol-free] group. The alcohol group participants didn’t do this,” Bartholow said. The researchers also found that the size of the brain’s alarm signal was strongly associated with participants’ mood at the time of the test, and that most of the participants in the alcohol group reported feeling “less negative” after drinking than before. “There are certain circumstances under which reducing the brain’s alarm signal could be seen as a good thing, because some people, like those with anxiety disorders, are hyper-sensitive to things going wrong. In some people, a small amount of alcohol can take the edge off those anxious feelings, but consistently drinking as a way to reduce anxiety can lead to serious problems, including alcoholism,” said Bartholow. “Generally speaking, having a strong brain response to mistakes promotes better self-control and helps people avoid making further mistakes in the future.” The study is to be published in the Journal of Abnormal Psychology.