Mark Tippens Reinitz

Memory-conjunction errors: Miscombination of stored stimulus features can produce illusions of memory

We demonstrate that subjects will often claim to have previously seen a new stimulus if they have previously seen stimuli containing its component features. Memory for studied stimuli was measured using a “yes”/“ no” recognition test. There were three types of test stimuli:target stimuli, which had been presented during study,conjunction stimuli, constructed by combining the features of separate study stimuli, andfeature stimuli, in which studied stimulus features were combined with new, unstudied, features. For both nonsense words and faces, the subjects made many more false alarms for conjunction than for feature stimuli. Additional experiments demonstrated that the results were not due to physical similarity between study and test stimuli and that conjunction errors were much more common than feature errors in recall. The results demonstrate that features of stored stimuli maintain some independence in memory and can be incorrectly combined to produce recognition errors.

Role of Attention in Face Encoding

Subjects studied faces in a full- or a divided-attention condition and then received a recognition test that included old faces, new faces constructed by combining facial features from previously studied faces («conjunction faces»), and partly or completely new faces. Full- but not divided- attention subjects responded «old» more often to old than to conjunction faces; all subjects responded «old» to these faces more often than to partially or completely new faces. Thus it is less attentionally demanding to encode facial features than it is to encode their interrelations. Dividing attention had identical effects on an incidental and an intentional learning group. Experiment 3 demonstrated that dividing attention primarily affected explicit recollection rather than stimulus familiarity

A Demonstration and Comparison of Two Types of Inference-Based Memory Errors

Participants viewed slides depicting ordinary routines (e.g., going grocery shopping) and later received a recognition test. In Experiment 1, there was higher recognition confidence to high-schema-relevant than to low-schema-relevant items. In Experiment 2, participants viewed slide sequences that sometimes contained a cause (e.g., woman taking orange from bottom of pile) but not an effect scene (oranges on floor), or an effect but not a cause scene. Participants mistook new cause scenes as old when they viewed the effect; false alarms to cause scenes and high-schema-relevant items increased with retention interval. Experiment 3 showed that the backward inference effect was accompanied by false explicit recollection, whereas false alarms to schema-high foils were based on familiarity. This suggests that the 2 types of inferential errors are produced by different underlying mechanisms.

Effects of spatially directed attention on visual encoding

The purpose in this study was to distinguish among possible mechanisms by which focused attention facilitates visual perceptual processing in a cued discrimination task. In two experiments, subjects verified the presence of an X in masked, briefly presented, four-letter arrays. On most trials, subjects were precued to the location of the stimulus array (valid-cue condition); however, sometimes a nonstimulus location was cued (invalid-cue condition). The exposure duration of the stimulus array was varied. In Experiment 1, there was a large effect of cue condition on hit probability, but no effect of cue condition on false alarm probability. In Experiment 2, there was a large effect of cue condition ond′. In both experiments, the stimulus duration needed to reach any given performance level was greater by a constant factor for stimuli in the invalid-cue than it was in the valid-cue condition. This suggests that visual information is acquired (or utilized) more rapidly from attended than from unattended locations.

Implicit and explicit memory for compound words

Subjects studied visually presented compound words (e.g.,toothpaste, heartache) and then received a recognition, perceptual identification, or word-fragment completion test that contained old, recombined (e.g.,toothache), and partially and completely new words. False recognitions increased with the increasing number of previously studied components; however, priming in perceptual identification occurred only for old words. Priming in word-fragment completion occurred for old and recombined words. Reducing the time available to solve word fragments, from 20 sec to 5 sec, did not affect the pattern of results; it is therefore unlikely that priming for recombined words resulted from the use of a recollection-based strategy. Memory tasks that involve a conceptual component access memories that are constructed from parts; memory tasks that are primarily perceptual do not access such memories.

False memories for compound words: Role of working memory

Subjects studied pairs of compound words; pair members were presented simultaneously (one above the other) for 2 sec or sequentially (one immediately following the other) for 1 sec each, and 6-sec interstimulus intervals separated the end of presentation of one pair and the start of that of another. A subsequent recognition test includedwithin-pair andbetween-pair conjunction foils (recombinations of stimulus parts from the same study pair and from separate pairs, respectively). Previous experiments using faces as stimuli have demonstrated that when faces are presented simultaneously there are many more false alarms to within-pair than to between-pair conjunction items, and when faces are presented sequentially there is an equal number of false alarms in those two conditions. However, Experiment 1 showed that for compound word stimuli there were equally high false alarm rates to both types of foils in both study conditions relative to completely new test items. Experiment 2 showed that when rehearsal of compound words was prevented, the pattern of conjunction errors was very similar to the one typically obtained for faces. In Experiment 3, subjects falsely recalled conjunctions of withinpair compound words but not conjunctions of between-pair words in the simultaneous-study condition; no conjunctions were recalled in the sequential-study condition. The results support the idea that working memory processing is necessary for binding stimulus parts together in episodic memory.

Influences of temporal factors on memory conjunction errors

Subjects viewed a series of faces presented two at a time for 16 seconds. Following either a 15-minute (Experiment 1) or 24-hour (Experiment 2) retention interval they received a recognition test that included old faces as well as faces constructed by recombining features from simultaneously presented study faces (simultaneous-conjunction condition), faces from successive pairs (near-conjunction condition), and faces that were two pairs apart (far-conjunction condition). In Experiment 1, false alarm rates decreased as the temporal distance between the relevant study faces increased. In Experiment 2, the false alarm rate in the simultaneous-conjunction condition was equal to the hit rate for old faces, and the false alarm rates for the other conditions was much lower. There was no effect of serial position during the study phase on the likelihood that parts of a face would later be miscombined to produce a recognition error in either experiment. The results suggest that witnesses to a crime are more likely to miscombine features of a to-be-remembered stimulus with those of another stimulus that was simultaneously present at the crime scene than with those of a stimulus encountered either earlier or later, especially when the test is delayed. Copyright

EFFECTS OF WOMEN'S STUDIES COURSES ON GENDER-RELATED ATTITUDES OF WOMEN AND MEN

Attitudes about feminism, gender equality, and gender differences were assessed for male and female students enrolled in three womens studies courses and four control courses at the beginning and end of an academic semester. Compared to control students, womens studies students agreed more with feminist and equality items, and disagreed more with gender difference items, at the beginning of the term. Nonetheless, belief in gender differences decreased among men, but not women, enrolled in womens studies courses. Additionally, womens studies courses produced increased feminist attitudes among women, but decreased feminist attitudes among the small sample of men in the study.

Effects of Semantic Priming on Visual Encoding of Pictures

We investigated the effects of semantic priming on initial encoding of briefly presented pictures of objects and scenes. Pictures in four experiments were presented for varying durations and were followed immediately by a mask. In Experiments 1 and 2, pictures of simple objects were either preceded or not preceded by the objects category name (e.g., dog). In Experiment 1 we measured immediate object identification; in Experiment 2 we measured delayed old/new recognition in which targets and distractors were from the same categories. In Experiment 3 naturalistic scenes were either preceded or not preceded by the scenes category name (e.g., supermarket). We measured delayed recognition in which targets and distractors were described by the same category names. In Experiments 1-3, performance was better for primed than for unprimed pictures. Experiment 4 was similar to Experiment 2 in that we measured delayed recognition for simple objects. As in Experiments 1-3, a prime that preceded the object improved subsequent memory performance for the object. However, a prime that followed the object did not affect subsequent performance. Together, these results imply that priming leads to more efficient information acquisition. We offer a picture-processing model that accounts for these results. The models central assumption is that knowledge of a pictures category (gist) increases the rate at which visual information is acquired from the picture.

Mechanisms of facilitation in primed perceptual identification

We investigated the mechanism that produces priming in perceptual identification. In Experiment 1, subjects studied a series of compound words (e.g.,outdoor,sideline); in Experiment 2, subjects studied a series of pictures (photographs) of objects. All subjects later received perceptual identification tests in which old (primed) and new (unprimed) words (Experiment 1) or pictures (Experiment 2) were presented for varying durations and masked. In both experiments, performance for primed and unprimed stimuli was predicted essentially perfectly by a model that assumes that prior exposure to a stimulus results in increased visual information-acquisition rate when it is subsequently encountered. An ancillary purpose of Experiment 1 was to test whether or not priming occurs for recombined words (e.g.,outline); there was no evidence for such priming at any exposure duration.