If you have a couple of stiff drinks at a party, you'll probably have a harder time remembering conversations than if you stick to soda. But you'll be just as likely to spontaneously think of the words you heard in those conversations.
That's one of the implications of a new study in Experimental and Clinical Psychopharmacology (Vol. 11, No. 2) on the effect of alcohol on memory in 54 men between 21 and 35 years old.
The study's finding--that alcohol impairs controlled memory processes but has no effect on automatic, perceptual processes--suggests that alcohol may leave well-learned habits untouched even as it impairs the ability to control one's behavior, says University of Pittsburgh psychologist Michael A. Sayette, PhD, who co-authored the study with graduate student Thomas R. Kirchner.
The finding could, for example, help explain why cigarette smokers are likely to relapse after drinking.
"Let's say you're a smoker who has tried to quit, and you've gotten pretty good at resisting cravings, but now you've had a few drinks," says Sayette. The urge to smoke will be just as strong as it ever was, he says, but the ability to control that urge could be seriously impaired.
The men in the study drank the equivalent of about three to four alcoholic drinks or a placebo before studying a word list. When tested later, the memory of those who drank vodka was significantly impaired compared with the memory of those who drank tonic water.
But not all forms of memory were equally impaired. Kirchner and Sayette found that automatic memory processes that determine whether someone spontaneously thinks of a word were unaffected. But controlled processes used when someone intentionally tries to remember were impaired.
The researchers were able to tease apart automatic and controlled processes by using the Process Dissociation Procedure (PDP), a technique devised by Larry Jacoby, PhD, of Washington University in St. Louis. Others have done this before, but Kirchner and Sayette were the first to administer drinks before the word list was studied, which Sayette says provides the strongest possible test of alcohol's effects.