The probability-matching decision rule in the visual discrimination of order

In three experiments, human Ss were required to decide, on each trial, which of two spatially proximate, nearly simultaneous, lights was illuminated first. The right light preceded the left on either .33 or .83 of the trials. When Ss were frequently informed of these values, then, regardless of the accuracy of performance, Ss adjusted the rate at which they made “right” responses to approximate the rate at which the right-first pattern was presented. These results are in clear agreement with an adaptation of Atkinson’s three-state detection model.