List length and the bizarreness effect: support for a hybrid explanation

The impact of processing time on the bizarreness and orthographic distinctiveness effects

The bizarreness effect and the orthographic distinctiveness effect (OD effect) are typical cases of secondary-distinctiveness-based effects. This study tested the simple attentional account or processing time hypothesis as a possible explanation of the bizarreness effect and the OD effect. In the bizarreness effect literature, this hypothesis gained support by some studies but was also discredited by other research. In light of these conflicting results, Experiment 1 was devised to test the processing time hypothesis in the bizarreness effect by using black-and-white concrete images and manipulating the time allotted for processing the stimuli (500 ms, 1000 ms, 3000 ms). Concerning the OD effect, no research has directly investigated the impact of processing time by examining the effect under varying amounts of study time. Experiment 2 was thus devised to investigate this same hypothesis in the OD effect and time allotted for processing the stimuli was manipulated (250 ms, 500 ms, 1000 ms, 3000 ms). Results did not support the processing time hypothesis since the magnitude of the bizarreness effect and of the OD effect was not modulated by the amount of time allotted for processing the stimuli. We refer to alternative explanations to account for these two secondary-distinctiveness-based effects.

Disentangling encoding versus retrieval explanations of the bizarreness effect: Implications for distinctiveness

Recall effects attributed to distinctiveness have been explained by both encoding and retrieval accounts. Resolution of this theoretical controversy has been clouded because the typical methodology confounds the encoding and retrieval contexts. Using bizarre and common sentences as materials, we introduce a paradigm that decouples the nature of the encoding context (mixed vs. unmixed lists of items) from the retrieval set (mixed vs. unmixed retrieval sets). Experiment 1 presented unmixed lists for study, and Experiment 2 presented mixed lists for study. In both experiments, significant bizarreness effects were obtained in free recall when the retrieval set intermixed items but not when the retrieval set consisted of only one item type. Also, Experiment 1, using a repeated testing procedure, did not reveal evidence for more extensive encoding of bizarre sentences than of common sentences. The results support the idea that retrieval dynamics primarily mediate the bizarreness effect, and perhaps more generally, distinctiveness effects.

Memory discrimination for self-performed and imagined acts: bizarreness effects in false recognition

Two experiments investigated the susceptibility of common and unusual action events to memory distortion under incidental learning and delayed testing conditions. Experiment 1 tested the influence of imaginal and enactment instructions at testing on memory discrimination for self-performed and imagined acts. The influence of hypnotic procedures at testing on memory discrimination for action events was tested in Experiment 2. The results of both experiments suggest that the likelihood of confusing details associated with separate, previously experienced unusual action events is greater than the likelihood of confusing details associated with separate, previously experienced common action events. Based on the results of both experiments, it is concluded that bizarreness has both memory-facilitating and memory-inhibiting qualities.

Tests of a cognitive-resource-allocation account of the bizarreness effect

The authors examined the role of cognitive-resource allocation in obtaining the often reported memory advantage for bizarre relative to common information by using the secondary-task method in 4 experiments. In Experiments 1 and 2, they investigated the relationship between differences in cognitive resource allocation during comprehension and in recall for common and bizarre information. In Experiments 3 and 4, they investigated the same relationship but measured cognitive-resource allocation during imaging rather than during comprehension. Although bizarre items required more time to comprehend and to image than did common items, the differences were not reliable predictors of the recall differences between item types. Furthermore, analyses of response latencies to a secondary task provided no compelling evidence in support of a cognitive-resource-allocation explanation of bizarreness effects. Implications for the development of a comprehensive model of the influence of bizarreness on memory are discussed.