Alcohol may not affect witness recall, new study finds

People with mild to moderate alcohol intoxication are no less accurate as witnesses when recalling details of what they have seen than sober people, according to a new study.

Research by Abertay University, Dundee, and London South Bank University, published in the journal Pharmacology, found that people who had drunk alcohol were less confident and recalled fewer details than those who had not, but were in fact no less reliable.

The research focused on people who had only mild to moderate alcohol intoxication and who were asked to recall events shortly afterwards. It compared people who had taken no alcohol with others who had drunk vodka and orange juice. Both groups were asked to recall details from videos showing a mock theft.

While participants were tested in pairs, each person watched a different version of the crime, although they were led to believe that they were watching the same video.

It was also found that people who discussed what they witnessed with others provided less reliable testimony. Half of the participants were allowed to discuss what they had seen before being asked to recall what they saw, and of these, seven out of eight gave at least one piece of incorrect information that they had not actually seen themselves, but had heard from their co-witness – a rate almost seven times higher than those going solely on their own recollection.

Dr Julie Gawrylowicz of Abertay University, co-leader on the study, said: "Contrary to perceptions commonly held by the general public and many professionals working within the criminal justice system, our findings suggest that mild to moderate alcohol intoxication does not make individuals more susceptible to incorporating misleading information obtained from a co-witness.

"Our work also shows that alcohol does impact recall completeness but not accuracy, so mild to moderately intoxicated witnesses may be regarded as a reliable source of information, even if questioned in an intoxicated state.

"It is important to note though, that this study tested memory at low to moderate intoxication levels, with a minimal delay before recall, and no other influencing factors."