Contributions of Specific Cell Information to Judgments of Interevent Contingency

Abstract

College students considered the possible effect of an experimental drug on a skin rash. The information came from a 2 × 2 contingency table involving receipt or nonreceipt of the drug and improvement or nonimprovement of the rash: Cell A = receipt-improvement; Cell B = receipt-nonimprovement; Cell C = nonreceipt-improvement; Cell D = nonreceipt-nonimprovement. Without numerical information, Ss judged cells to be ordered A > B > C > D. The same order held when the contribution of each cell was derived from the contingency judgments of other subjects given numerical information. No such consistency was seen when one group of Ss made both judgments; whether individual Ss equally or unequally assessed the importance of the four cells, their contingency estimates showed cell use to be ordered A > B > C > D. These findings may result from strong biases that Ss harbor in processing contingency information.