You and two of your co-workers have just interviewed a candidate for a job opening at your law firm.

1. You and two of your co-workers have just interviewed a candidate for a job opening at your law firm. Your boss asks you what inferences you drew about the job candidate during the interview. What can you do to maximize your likelihood of making a correct inference?

2. John is a young, energetic, muscular, and outgoing individual. Estimate the likelihood that he a) is tall and likes sports. and b) is tall, likes sports, and has lots of friends.

3. You and a friend are taking a walk. While on your walk, you pass a middle-aged woman. You tell your friend that she seems like someone who is very intelligent. Your friend agrees but adds that she seems to be very confident as well. Who is more likely to be correct? Why?

Discussion Question 1. What is a stereotype? How do stereotypes relate to the findings of this demonstration?

Typical Reasoning Minimum time to complete this experiment: 20 minutes

Background:

Tversky and Kahneman (1983) are well known for their research showing that people’s estimates of probability are often very different from the objective probabilities. The reason, they argue, is that people often use heuristics to help them estimate the answer. Heuristics can be seen as sacrificing some accuracy for an increase in speed. By using heuristics, people can very quickly come up with an answer that is usually good enough for day-to-day purposes. These heuristics, however, can lead to incorrect judgments.

One of the most striking errors is known as the conjunction fallacy. In its most simple form, it says that people think that having both A and B occur is more likely than having just A occur or just B occur. According to objective probabilities, the probability of two events occurring has to be less than the probabilities of either of the events happening by itself. In some circumstances, however, people are more likely to say the conjunction (having both events occur) is more likely.

In particular, the conjunction fallacy is more likely when the items are typical than when they are atypical. For example, read the following: Julie is 26 years old, has a degree in physical education, has been physically fit since childhood, and loves the outdoors. People think it is more likely that Julie is a ski instructor who also teaches aerobics (a conjunction involving an activity thought to be more typical of ski instructors) than that Julie is a librarian who also teaches aerobics (a conjunction involving an activity thought to be less typical of librarians). When the activity is particularly typical, the conjunction can be thought more likely than the single events (e.g., that Julie is a ski instructor). This demonstration is based on an experiment by Shafir, Smith, and Osherson (1990). You will read short descriptions about several people and you will be asked to rate the probability that these people have certain professions and/or engage in certain activities.