Pragmatic Reasoning Schemas

This experiment is based on the following paper:

Cheng, P. & Holyoak, K. (1985). Pragmatic reasoning schemas. Cognitive Psychology, 17, 391-416. Reprinted by permission of Academic Press.


When people reason about realistic situations, Cheng and Holyoak proposed there are three methods available. First, they could deduct a set of abstract, logical rules for building inferences that could apply to a variety of different contexts. Second, they could draw on previous experiences to help form a judgment about the specific situation. Or third, they could use pragmatic reasoning schemas, which are generalized sets of rules defined in relation to classes of goals that could help them prediction the outcome in a given situation.

To test their ideas Cheng and Holyoak use a modified version of the Wason selection task.

In this task subjects are informed that they will be shown cards that have numbers on one side and letters on the other, and are given a rule such as, “If a card has a vowel on one side, then it has an even number on the other.” Subjects are then presented with four cards, which might show an “A,” a “B,” a “4,” and a “7” and are asked to indicate those and only those cards that must be turned over to determine whether the rule is true or false." p.391

Other studies have shown this task can be very difficult, but when the task is rewritten to include common items in a realistic context, such as stamps on letters, it can be much easier. Some researchers have proposed that people do poorly due to fallacies in their logical reasoning or because they have not had any other experiences like this task which could guide their judgment. Cheng and Holyoak, however, argue that Wason task is difficult to do because people prefer to reason using pragmatic schemas, and the Wason task does not provide information which can be readily organized into a familiar schema from which they could form logical inferences.


The full text describing the experiment is available here.

The experiments are available below. (25.6 KB) (29.1 KB)