Looking behind: Turning cards in the selection task.

Wason's selection task requires that one imagine which of four cards, each of which has a letter on one side and a number on the other, one would have to turn over to determine whether a statement about the cards is true or false. For example, one might see four cards showing T, H, 6, and 4 and be asked to say which card or cards one would have to turn over to determine whether a statement in the form of If a card has T on one side, it has 4 on the other is true. In the great majority of experiments with this task no cards are actually turned.

Knowledge assessment: Squeezing information from multiple-choice testing.

Knowledge assessment via testing can be viewed from two vantage points: that of the test administrator and that of the test taker. From the administrator's perspective, the objective is to discover what an individual knows about a domain of interest. From that of the test taker, the challenge is to reveal what one knows.

On producing random binary sequences.

This experiment addressed the opinion prevailing among researchers that people are poor at producing random binary sequences. Participants tried to produce sets of sequences of outcomes of imaginary coin tosses that could not be distinguished statistically from sets expected from actual coin tossing. The results generally support the conclusion that people are not very good at this task, although the distributional properties of the sets of sequences produced are qualitatively similar to those expected of sets produced by a random process.