Congruity Effect and Bizarreness Effect on Incidental Memory

The present study investigated whether or not the image determined the occurrence of congruity effect and bizarreness effect on incidental memory. The subjects performed an orienting task involving two conditons, followed by unexpected free recall and cued recall tests. In a choosing condition, the subjects in congruity group were asked to choose one of the two sentence frames into which each target could fit more congruously, whereas those in image group were asked to choose one of the two ones into which each target could arouse more vivid image. In a rating condition, the subjects in congruity group were required to rate the congruity of each target to its sentence frame on 5-point congruity scales, whereas those in image group were asked to rate the vividness of image that aroused by each target and its sentence on 5-point vividness scales. Four types of sentence frames were provided; congruous image sentences, congruous nonimage sentences, incongruous image sentences and incongruous nonimage sentences. In a free recall test, the bizarreness effect, namely superiority of incongruous sentences to congruous sentences was observed only for image group in choosing condition, but the effect was not observed for both groups in rating condition. In a cued recall test, the congruity effects, namely superiority of congruous sentences to incongruous sentences were observed for both group in rating conditions, but the effects was not observed only for image group in choosing condition. These results were interpreted as showing that the image of each target and its sentence frame determined the occurrence of the congruity effects and the bizarreness effects on incidental memory