The imagery effect and frequency discrimination.

A 300-item list of concrete and abstract nouns with varying frequency of occurrence was presented at a 1-sec rate to 144 subjects under imagery or nonimagery instructions. Subjects were then tested on 72 word pairs homogeneous and heterogeneous with respect to concreteness, where the more frequent member of each pair was to be chosen. Frequency discrimination was found to be a function of relative rather than absolute frequency differences between pair members. In addition, a subjective frequency bias for abstract items was found, with the best performance when the more frequent alternative was abstract and less frequent alternative concrete. The worst performance was for the reverse condition, while that for pair types homogeneous with respect to concreteness fell in-between, with better performance when both alternatives were concrete. The results suggest that the role of imagery may be to produce more discriminable subjective relative frequency differences between alternatives and that the imagery effect generally found in verbal discrimination learning may be reconcilable with frequency theory as it currently stands.