By Emily Reynolds

Having a bit of a fuzzy memory is not an uncommon side effect of having had too much to drink the night before — and the details we do remember are often somewhat limited. The same can also be true for our attention when drunk: we’re only able to concentrate on what’s going on in front of us and not what’s happening elsewhere.

This phenomenon has been termed “alcohol myopia”: attentional shortsightedness related to alcohol consumption. A new paper in the Journal of Psychopharmacology suggests this shortsightedness may apply to human faces, too — and that it could have an impact on how well people can identify perpetrators of crimes they witness while drunk.

To explore the idea, Alistair Harvey and Danny Tomlinson recruited 76 students from a particularly apposite place — a university bar. Participants, all of whom had normal or corrected to normal vision, were first shown twenty-one photographs of young white adult male faces. Then five minutes later, they saw a selection of these “old” faces again, amongst a number of previously unseen “new” faces of the same demographic and description.

Some faces were shown in full, while others showed only “external” features such as hair and face shape, or direct “internal” facial features like the eyes and mouth. Participants were asked to identify which photographs showed old faces and which showed new ones, and indicate how confident they were in their identifications on a scale of one to nine.

Surprisingly, full face recognition was not any worse in those who had been drinking alcohol compared to sober participants. But drinkers were more likely to recognise external faces than their internal facial features, and those with greater breath alcohol levels performed worse when it came to these internal faces.

Unfamiliar faces are normally encoded “holistically” — individual features and their relationship to each other are all integrated into a whole memory. But the team suggests that alcohol disrupts this process, thus making memory more feature-based than holistic.

And the finding could have implications for how intoxicated witnesses later identify criminal suspects: the encoding bias towards external features could make witnesses less likely to identify a perpetrator who has changed or disguised their hair, for example — or more likely to falsely identify an innocent line-up filler with similar external features.

How gender impacts this phenomenon is yet to be established: all photos were of men, but women tend to have more diverse hairstyles, so there may be differences in memory of male and female faces, as previous studies with sober participants have suggested. Would more diverse styles and colours of hair make external features more distinctive and therefore easier to remember, for instance?

The study is obviously limited by its design: unrecorded drug consumption may also have impacted participants’ ability to remember faces, and their history and their relationship with alcohol wasn’t examined. How much and how frequently someone drinks could be an additional influence on memory.

But the research does suggest that facial recognition is affected in subtle and often counter-intuitive ways by the consumption of alcohol. When it comes to remembering exactly who you met the night before, this might not seem like too big a deal. But when witnessing a crime, our ability to recall what we saw may not be so insignificant.

– Alcohol myopia and the distracting effects of hair in face recognition

Emily Reynolds (@rey_z) is a staff writer at BPS Research Digest