It is no secret that not all people respond the same to alcohol. But does alcohol heighten our natural tendencies?
Research on ego depletion (e.g., by Roy Baumeister, Florida State University) shows that the brain has a limited amount of self-regulatory abilities (self-control), just like we have a limited amount of use of any muscle. When these abilities have been depleted we then act more impulsively and with less concern for other people, both in terms of how they are feeling and in how they might be perceiving us. For instance, research shows that people show higher levels of racism when their self-regulatory capacity has been depleted (even by something as simple as watching a movie that is funny, but trying not to show emotion).
Alcohol has clear effects on how we are able to manage our impulses and self-control. When we are drinking we are much more prone to say and do things without (or at least with less) regard for the consequences.
From this perspective, alcohol should cause people to behave in ways that they typically block. That is, bring out how people would act, their natural personalities, if they were not able to control themselves. This would suggest that aggressive people naturally should become more aggressive when drinking alcohol, but that less or non aggressive people should not have this tendency.
This is exactly what research by Nathan Dewall (associate professor of psychology, University of Kentucky) and colleagues found.
In this study, they had participants answer questions about how violent and aggressive they are. Participants then were randomly assigned to drink alcohol or to drink a placebo drink that tasted, smelled and loked like alcohol, but was not. After this, participants were able to give electric shock to a person in another room (this was actually not done, but participants believed that this was done).
The findings indicted that people who scored higher on a measure of aggression going into the study had more aggression when drinking alcohol than the placebo drink. This was not the case for people who scored low in aggression entering the study.
In other words, only people who have aggressive personalities when not drinking became more aggressive because of alcohol.
They get punch drunk.