It’s no surprise that excessive drinking results in memory loss during the binging. What’s more surprising is that teenagers who are heavy drinkers may be permanently affecting their memories even while sober. In particular, prospective memory (the ability to remember to carry out a future activity, such as show up for an appointment or return books to the library) appears to be damaged in teenaged drinkers.
Tom Hefferman of Northumbria University led a study testing the memory of 50 university students who did not use other substances (such as ecstasy, marijuana or tobacco) and had not had a drink in at least 48 hours. 21 of the students were classified as binge drinkers, meaning that at least twice a week they drank 6 units of alcohol if women and 8 if men. One unit equals either a glass of wine or a beer. The other 29 participants were non-bingers.
All the volunteers were shown a ten-minute video clip of a shopping area. Prior to seeing the clip, they had been asked to perform specific actions when particular locations appeared on the video. The binge-drinkers remembered significantly fewer of the tasks than their non-binge drinking cohorts. Yet, when asked to evaluate themselves, the binge drinkers perceived themselves to have perfectly functioning memories. In other words, they did not realize that they were at all impaired.
It would be interesting to see whether binge drinking, if begun later in life, also affects prospective memory to the same degree. The authors of the study suspect that the damage would be much more severe in teens, since their brains are still developing.