THE ROLE OF ITEM FREQUENCY IN THE COLOR-WORD CONTINGENCY EFFECT

When words and print colors are correlated in a stimulus set, and an individual is to identify the colors, the irrelevant word information influences performance. Specifically, responses are faster and more accurate when stimuli are words that occur frequently in a particular color (high-contingency items) than when words rarely appear in that color (low-contingency items).  Typically, high-contingency are more frequent than low-contingency items. The performance advantage for high-contingency items is called the color-word contingency effect. One mechanism hypothesized to explain the contingency learning effect is that responses are influenced by retrieving memories of recent similar trials. According to this explanation, responses to high contingency trials are facilitated by it being likely that memories of recent trials include other such trials.To investigate the role of frequency independent of contingency, we constructed stimulus sets that contained 1 or 2 perfect contingency words (i.e., the word was associated with one color) and 1 or 2 no-contingency words (half of the occurrences of the word were in one color and half in a different color).  In two conditions, all items occurred with equal frequency.  If the contingency effect is due solely to the relative frequency of items, it should be attenuated or eliminated when the frequency of perfect-contingency and no-contingency items is equated. Participants identified the color in which words were printed.   The results provided suggestive, but not conclusive, evidence that equating the frequency of items attenuates the contingency effect. On average, the contingency effect was 8 ms smaller in the conditions in which all items occurred with equal frequency than in conditions in which they did not (one-sided p = .09).  There was an overall effect of contingency:  Even in conditions in which the contingency effect may be attenuated, responses to perfect contingency items were faster than responses to no contingency items.