Stimulus Encoding and Additivity of Effects in a Card Sorting Task

The work of Sternberg (1969) suggests the independence from one another of the times required for encoding a stimulus, matching it against a set of stored representations in memory and responding. A card sorting experiment was performed to test some implications of this position. The variables manipulated were the number of different letters to be sorted into a pile, orientation of the letter on a card, and whether letters encodable according to a shared physical characteristic were to be sorted into the same (within) or different (between) piles. As predicted, orientation of the letter and number of different letters to be sorted/pile affected sorting time only in the between pile condition where the effects were observed to be additive.