Alcohol helps in remembering the good things and in forgetting the bad things and is therefore is addictive, according to researchers at the University of Sussex.
According to the research team, alcohol is addictive because it erases the worst memories of being drunk.
The study has found that alcohol affects memory in a selective manner - making it easier to remember the good things about a party but harder to recall the bad things that happen after having too much.
Studies into the memories of people engaged in heavy drinking have shown that it is the inability to remember the worst excesses of a night out - while remembering the happy things that led up to them - is one of the main causes of repeated binge drinking.
"The effects of alcohol on mood are known contributors to its use and abuse. It is less known how its effects on memory and inhibitory control add to alcohol being and addictive drug," the Independent quoted Professor Theodora Duka of Sussex University, as saying.
"Material acquired in an intoxicated state is less effectively retrieved in a sober state. Thus people who abuse alcohol forget the consequences of intoxication during periods of abstinence," Professor Duka said.
Professor Duka, who was speaking at the British Association for the Advancement of Science Festival, explained that the effect of alcohol on memory is one of the least-understood aspects of alcohol abuse, yet it could be one of the most important in terms of explaining why the drug is o powerfully addictive.
"The effect of alcohol to weaken control processes intuitively appears to be the most important contributor to the development of alcohol addiction, since alcohol addiction is perceived to be an inability to control drinking," she said.
"Alcohol facilitates memories for emotional events experienced before intoxication - mostly positive - and impairs memories for emotional events experienced after intoxication - often negative - biasing memory to positive effects of alcohol, and support [for] further drinking," she added.
Memory tests on volunteers who were shown emotion-laden images before, during and after a bout of drinking found there was a clear degradation in memory as the alcohol began to build up in their bodies.
"Alcohol facilitated memory for material seen after its administration. More importantly, under the influence of alcohol, emotional images seen before alcohol consumption were recalled more whereas emotional images seen after alcohol consumption were recalled less," she said.