A Common Mechanism Is Possibly Underlying the Shift in Perceptual and Conceptual Judgment Produced by Irrelevant Information

This paper presents two experiments exploring context effects on human judgment and testing JUDGEMAP’s predictions that irrelevant information such as the color of the stimulus can produce a contrast effect with respect to skewed stimuli set to be judged. The first experiment demonstrates the effect on a perceptual judgment task (judging the length of lines which are colored in red and green), while the second experiment demonstrates exactly the same effect on a conceptual judgment task (judging the age of a person when the absolute age is presented by numbers with colored digits – red and green). These results rule out the “recalibration ” of the perceptual system explanation. The fact that the same effects were obtained in both cases prompts for a common explanation. JUDGEMAP provides such an explanation: the color is used in retrieving past instances in WM based on the spreading activation mechanism and thus the comparison set becomes biased. The biased comparison set which is then mapped on the scale elements produces a shift in the mean ratings