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.     

The imagery effect and phenomenal background frequency in verbal discrimination learning

A series of four experiments was conducted to assess the role of phenomenal background frequency in verbal discrimination learning and its possible involvement in the imagery effect. The initial two experiments produced a reliable imagery effect for mixed and unmixed lists with respect to concreteness of pair members, regardless of phenomenal frequency manipulations, with words high in objective background frequency. No effects were found for phenomenal background frequency. Experiment 3 involved phenomenal frequency ratings for 200 abstract and 200 concrete words. Experiment 4 evaluated the role of phenomenal background frequency for a mixed list using words low in objective frequency. A reliable imagery effect was again found with no effects for phenomenal frequency. An alternative hypothesis involving differential accrual of situational frequency to abstract and concrete items during verbal discrimination learning to explain the imagery effect was also tested by Experiment 4 but was not supported by the data.