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CLEVER rats tend to become heavy boozers. This discovery doesn’t mean that the brightest people are the most likely to get drunk, but it may illuminate patterns of behaviour that can turn people into hard-core alcoholics.

Many studies have shown that your genetic make-up influences your risk of becoming an alcoholic (91av, 27 November 1999, p 38). But research on rodents has shown that behaviour may also be a more obvious indicator of risk. Novelty-seeking rats, who like exploring new habitats, tend to drink a lot of alcohol if given the chance. And rats bred to be good at navigating mazes are unusually keen on a tipple.

To try to understand the influence of genes and behaviour in more detail, Brian Smith of Concordia University in Montreal and his team monitored 60 male rats, which had no special pedigree, as they learned to navigate a maze to find a reward of honey-flavoured rice treats. Each rat had a daily trial for 19 days, with performance being scored on speed and accuracy. Then the team measured the amount of alcohol the rats drank voluntarily over five days.

It turned out that the best maze-learners were among the rats that drank the most alcohol. As good learners, they may have quickly linked the smell and taste of alcohol to its feel-good factor, says Smith. In animals that drank little alcohol, possibly because they simply had an aversion to the taste, the same trend didn’t appear.

Smith says the results support the idea that factors other than genes, brain chemistry and environment contribute to heavy drinking. Behavioural traits such as learning ability could be a possible risk factor—even in people.

“When you’re young and experimenting with alcohol, you get drunk a lot, you throw up and then you have hangovers,” says Smith. “But as people get older, most learn to know their limits.” He thinks improved learning skills might be one factor that makes a minority of people continue to get sozzled, leading to alcoholism.

Smith admits that drunken rats can only hint at useful answers. “Rat models are not going to approach the totality of the human experience,” he says. “But they do allow you to isolate specific aspects of behaviour, and that might tell you where to look in people.”