Drinking alcohol improves memory for information learned before the drinking episode began, new research suggests.

In the University of Exeter study, 88 social drinkers were given a word-learning task. Participants were then split in two groups at random and told either to drink as much as they liked (the average was four units) or not to drink at all.

The next day, they all did the same task again -- and those who had drunk alcohol remembered more of what they had learned.

The researchers are keen to stress that this limited positive effect should be considered alongside the well-established negative effects of excessive alcohol on memory and mental and physical health.

"Our research not only showed that those who drank alcohol did better when repeating the word-learning task, but that this effect was stronger among those who drank more," said Professor Celia Morgan, of the University of Exeter.

"The causes of this effect are not fully understood, but the leading explanation is that alcohol blocks the learning of new information and therefore the brain has more resources available to lay down other recently learned information into long-term memory.

"The theory is that the hippocampus -- the brain area really important in memory -- switches to 'consolidating' memories, transferring from short into longer-term memory."

The effect noted by the researchers has been shown under laboratory conditions before, but this is the first study to test it in a natural setting, with people drinking in their homes.

There was also a second task which involved looking at images on a screen.

This task was completed once after the drinkers had drunk alcohol and again the following day, and the results did not reveal significant differences in memory performance post-drinking.

The study's participants were 31 males and 57 females, aged 18-53.