Acquisition and extinction of an alcohol-opposite conditioned response in humans.

Twelve social drinkers were given a 0.7 g/kg dose of alcohol mixed with a distinctively flavoured drink in each of five sessions, and the same drink with no alcohol in a further three sessions. All sessions were conducted in the same room. The alcohol increased heart rate, but with repeated administration change was slower to begin. In the first placebo session the change in heart rate was a decrease below baseline level, particularly in the early part of the session. Repeated administration of the placebo resulted in a diminution of this alcohol-opposite conditioned response.