Analyzing an experiment
A researcher was interested in the effects of alcohol on perceptions of physical attractiveness of the opposite sex. To study this, he used students from two of his classes, a senior seminar for psychology majors that met one evening a week from 6 to 9 p.m., and a first-year introductory psychology class that met two mornings a week at 10 a.m. Because the seniors were all at least 21 and, thus, legally able to drink, he assigned them all to the condition that received 2 oz. of alcohol mixed in with 6 oz. of orange juice. The first-year students were assigned to the “placebo” alcohol condition, in which they received 2 oz. of tonic water (which tastes like alcohol) mixed in 6 oz. of orange juice. These students believed that they were really being served alcohol as part of the psychological study.
Students were invited to participate in the study if they had a free hour after their class with the professor. The professor conducted the study on a Thursday, on a day when the introductory class had had an exam. Students drank either the alcohol or the placebo drink, waited 30 minutes in a lounge for the “alcohol” to take effect, and then sat at a computer and performed a five- minute task in which they rated various faces of the opposite sex on physical attractiveness.
The group that had received alcohol rated the faces as more attractive than the group that did not receive alcohol, and the professor concluded that alcohol makes people of the opposite sex appear more attractive.
Is the professor’s conclusion a reasonable one? Discuss the elements of the study design to support your answer (e.g., refer to the weaknesses of the experiment that make the results less convincing). If you find the conclusion unreasonable, then design a proper experiment to test the professor’s hypothesis.
