Caffeine

Caffeine is widely used for its stimulant properties. Most people think of caffeine as improving their ability to think clearly, but a great deal of the research shows that it actually does not improve human memory in a variety of psychological tests.

One study administered 100mg doses of caffeine to college students and found that their ability to remember lists of words that they had just heard was diminished when they were given caffeine. In another study, college students were given either 0, 2, or 4mg of caffeine for every kilogram of their body weight. At the 2mg rate, that would be 127mg for a 140 Ib. person. A 5 oz. cup of coffee can contain from 40 - 180 mg caffeine. Female students had a more difficult time of remembering lists of words that were read to them slowly when they were given caffeine, and otherwise no memory effects, good or bad were noted by the researchers. Thirty-two men were randomly given 0, 125, 250mg of caffeine and then given a recall test, a reaction time test, and something called a Stroop test that involves confusing data. They performed poorly with the high dose on the Stroop test. The researchers wrote, "Caffeine may have a deleterious effect on the rapid processing of ambiguous or confusing stimuli...". This sounds like a description of modern life.

A 1983 study found that combining caffeine and alcohol actually slowed the reaction time of 8 subjects. The caffeine and alcohol combination made the subjects more drunk than alcohol alone. So much for the popular myth that giving a drunk some coffee is a good way to get him or her back on the road.

Coffee contains many chemicals other than caffeine. There are at least three opiate-like compounds in coffee. This probably accounts for coffee drinkers describing coffee as relaxing. These opiate-like compounds, which are found even in decaffeinated coffee, may also in part account for coffee's addictive qualities.