Perceptual interference and hemispheric specialization

Two experiments evaluated the effect of stimuli presented at fixation on the recognition of faces or random shapes presented to the left or right visual half-field (VF). Increasing the processing demands of the center stimulus produced a large, linear decrease in recognition from both VFs for both faces and shapes. Recognition of random shapes was decreased more in the right visual field by center digits and in the left VF by center faces and shapes. In addition, interference was found between the VF faces and the center digits to the left of fixation. It was concluded that differences in the processing capacity of the two hemispheres are a function of the verbal-nonverbal nature of the stimuli at a later stage in processing but that the two hemispheres may also differ along other perceptual dimensions at an earlier stage of visual recognition.     

A demonstration of shape constancy

In order to compare the recognition of objective (defined in three dimensions) and projective (on the frontal-parallel plane) shapes, subjects were asked to identify angles (either objective or projective) on random polygons that were displayed in complex and meaningful photographic slides in the frontal-parallel plane. The subjects’ judgments corresponded much more closely to the objective than to the projective shapes, almost independently of which of the two shapes they were asked to judge and of whether the slides were presented in a normal upright orientation or were rotated 180 deg. The results are incompatible with the strong form of the shape-slant hypothesis, which assumes that the primary perceptual information concerns the properties of the projective retinal image. The results indicate, instead, that a tacit conception of three-dimensional space is primary in the perceptual process.     

Memory for lateral orientation of slides in picture stories

Three picture stories were constructed by taking slides of people involved in three different activities. Two sequences of these slides were presented. Subjects were asked whether or not each slide in the second sequence was in the same lateral orientation as in the first sequence. Experiment 1 presented the slides in correct or random sequence and in correct or random lateral orientation (2 by 2 design). The two groups who received correct orientation excelled in recognition of orientation in the test series. Experiment 2 replicated the random orientation condition, found that pre-warning of the recognition task had no effect on performance, and suggested that these subjects did not make use of the events in determining laterality. Experiment 3 replicated the correct order and orientation condition and further revealed that new but appropriate slides in the test series were accurately judged as to lateral orientation which fit the context of the original stories.     

Spatial Repetition Blindness Is Modulated by Selective Attention to Color or Shape

Subjects reported either the colors or shapes of two simultaneous masked letters. Our first study found that they were less accurate when the reported features were identical ("repetition blindness," or RB), while repetition along the unreported dimension had no effect. Three follow-up studies confirmed that when the same dimension was judged (overtly or covertly) for both stimuli, performance was only affected by repetition along that dimension. However, when different dimensions were judged for the two stimuli, performance was affected by repetition on both dimensions. These findings support new conclusions about both RB and visual attention. First, RB depends critically on visual attention, rather than simply on the stimulus presented or the overt response required. Second, while attention can be restricted to a single visual dimension, this is efficient only when the same dimension is selected for both objects. Selecting the color of one object and the shape of another simultaneous object results in both dimensions being accessed for both objects.     

The effect of temporal delay and spatial differences on cross-modal object recognition

In a series of experiments, we investigated the matching of objects across visual and haptic modalities across different time delays and spatial dimensions. In all of the experiments, we used simple L-shaped figures as stimuli that varied in either the x or the y dimension or in both dimensions. In Experiment 1, we found that cross-modal matching performance decreased as a function of the time delay between the presentation of the objects. We found no difference in performance between the visual-haptic (VH) and haptic-visual (HV) conditions. Cross-modal performance was better when objects differed in both the x and y dimensions rather than in one dimension alone. In Experiment 2, we investigated the relative contribution of each modality to performance across different interstimulus delays. We found no differential effect of delay between the HH and VV conditions, although general performance was better for the VV condition than for the HH condition. Again, responses to xy changes were better than changes in the x or y dimensions alone. Finally, in Experiment 3, we examined performance in a matching task with simultaneous and successive presentation conditions. We failed to find any difference between simultaneous and successive presentation conditions. Our findings suggest that the short-term retention of object representations is similar in both the visual and haptic modalities. Moreover, these results suggest that recognition is best within a temporal window that includes simultaneous or rapidly successive presentation of stimuli across the modalities and is also best when objects are more discriminable from each other.     

False memories in music listening: exploring the misinformation effect and individual difference factors in auditory memory

ABSTRACT

The study of false memory has had a profound impact on our understanding of how and what we remember, as shown by the misinformation paradigm [Loftus, E. F. (2005). Planting misinformation in the human mind: A 30-year investigation of the malleability of memory. Learning & Memory, 12(4), 361–366. doi:10.1101/lm.94705]. Though misinformation effects have been demonstrated extensively within visual tasks, they have not yet been explored in the realm of non-visual auditory stimuli. Thus, the present study aimed to investigate whether post-event information can create false memories of music listening episodes. In addition, we explored individual difference factors potentially associated with false memory susceptibility in music, including age, suggestibility, personality, and musical training. In two music recognition tasks, participants (N?=?151) listened to an initial music track, which unbeknownst to them was missing an instrument. They were then presented with post-event information which either suggested the presence of the missing instrument or did not. The presence of misinformation resulted in significantly poorer performance on the music recognition tasks (d?=?.43), suggesting the existence of false musical memories. A random forest analysis indicated that none of the individual difference factors assessed were significantly associated with misinformation susceptibility. These findings support previous research on the fallibility of human memory and demonstrate, to some extent, the generality of the misinformation effect to a non-visual auditory domain.     

An analysis of the visual component in recognition memory for verbal stimuli

Forty Ss were given a continuous recognition memory test in which each word was presented twice, either in the same print or in different print on the two occasions. The results showed that (a) recognition performance was facilitated to a small but statistically significant extent in the same-print condition and that (b) Ss could reliably report first presentation print for recognized items for at least 1^1/2 rain. In a second experiment, the stimuli used were nonsense strings of. from five to seven letters instead of words. This manipulation increased the same-print advantage in recognition but reduced Ss’ ability to report first print form. The results indicate that information about the physical features of verbal stimuli is retained in a visual code that is partially’ or wholly independent of the verbal code for the same stimuli. The results are inconsistent with the conclusion that the visual code is stored only as a dependent attribute of the verbal code in memory.     

Olfactory stimuli as context cues in human memory

Olfactory stimuli were used as context cues in a recognition memory paradigm. Male college students were exposed to 50 slides of the faces of college females while in the presence of a pleasant or an unpleasant odor. During the acquisition phase, ratings of physical attractiveness of the slides were collected. After a 48-hr delay, a recognition test was given using the original 50 slides and 50 new slides. The recognition test was conducted with either the original odor or the alternative odor present. A no-odor control group did not receive olfactory cues. The attractiveness ratings indicated that the odor variations had no effect on these social judgments. Analyses of d' scores, hits, and false alarms for the recognition performance indicated support for the predicted interaction in which presence of the same odor at both sessions led to better overall performance.     

Spare the rod and spoil the icon

Short-term visual storage was investigated with a successive field paradigm, so that correct performance depended upon combining visual information from two targets that were never on simultaneously. In the first two experiments, the stimuli consisted of two slides, each containing a 10' red dot on a gray surround, and separated by an interstimulus interval (ISI) from 20 to 400 msec. Subjects had to determine if the dots were vertically or horizontally aligned. In Experiment 1, the stimuli had either no contrast for the rods or no luminance contrast for the cones or high contrast. At short ISIs the cone contrast determined performance, whereas at long ISIs the rod contrast determined performance. In fact, when the dots were invisible to the rods, the task was impossible for long ISIs. In Experiment 2, performance was compared for zero log rod contrast and for small departures from zero. Even a small departure from zero log rod contrast resulted in above-chance performance. In Experiment 3, the stimuli were luminous rectangles and the task was to decide whether or not a 4' spatial gap was present between the two successively presented rectangles. Wavelength, luminance, and ISI were varied under both photopic and scotopic adapting conditions. The result was that the rods performed the task for ISIs of 150 msec or longer under scotopic conditions and under the photopic conditions that we were able to test. The results of the experiments taken together are consistent with the hypothesis that the cone icon is short, whereas the rod icon is robust and long lasting.     

Recognition of Concrete and abstract Pictures as a Function of Poststimulus Interval

This study examined picture recognition of concrete common objects and abstract random shapes under two presentation conditions: The durations of the unfilled intervals (off-time duration) that followed the presentation of the pictures were varied either randomly or in blocks. The major findings were: (a) recognition of the concrete pictures was better than recognition of random shapes, (b) the off-time duration did not influence recognition of either type of picture under the random presentation condition, and (c) under the block presentation condition, recognition of the concrete pictures increased as a function of off-time duration, whereas the effect of off-time duration was not found for the abstract shapes. The results were interpreted as suggesting that a longer off-time duration is necessary for abstract shapes so that stimulus differentiation, verbal encoding, visual analogizing, and rehearsing may be utilized in processing.     

View combination: a generalization mechanism for visual recognition

We examined whether view combination mechanisms shown to underlie object and scene recognition can integrate visual information across views that have little or no three-dimensional information at either the object or scene level. In three experiments, people learned four “views” of a two dimensional visual array derived from a three-dimensional scene. In Experiments 1 and 2, the stimuli were arrays of colored rectangles that preserved the relative sizes, distances, and angles among objects in the original scene, as well as the original occlusion relations. Participants recognized a novel central view more efficiently than any of the Trained views, which in turn were recognized more efficiently than equidistant novel views. Experiment 2 eliminated presentation frequency as an explanation for this effect. Experiment 3 used colored dots that preserved only identity and relative location information, which resulted in a weaker effect, though still one that was inconsistent with both part-based and normalization accounts of recognition. We argue that, for recognition processes to function so effectively with such minimalist stimuli, view combination must be a very general and fundamental mechanism, potentially enabling both visual recognition and categorization.     

Effects of test sequence on anterograde and retrograde impairment of negative emotional scenes1

Abstract: The present study examined recognition for sequences of scenes depicting emotional compared with neutral events. In two experiments, participants were presented with a thematic series of 18 slides of scenes in which the content of two critical scenes in the middle of the series were either emotional (dead men's bodies) or neutral (an opera). A two‐item, forced‐choice recognition paradigm was used to test participants’ immediate memory performance of all 18 slides of scenes. In Experiment 1, anterograde and retrograde amnesic effects were observed for the emotional, but not the neutral scenes when a test sequence of scenes was used that did not match the original presentation order. In contrast, in Experiment 2 the test sequence matched the order seen during the original presentation, and both the anterograde and retrograde amnesic effects were not found. These results indicate that the reinstatement of the original event context is an important factor for the recognition of negative emotional memories.     

The effects of intradimensional and extradimensional shifts on visual discrimination learning in humans and non-human primates

Human subjects and non-human primates (the common marmoset) were trained on a series of reversals of both a simple (stimuli varying along one dimension) and compound (stimuli varying along two different dimensions) visual discrimination, using computer-generated stimuli. They were then shifted to a third series of reversals using completely novel compound stimuli. Those humans and marmosets for which the previously relevant dimension remained relevant, following the shift (shapes to shapes or lines to lines; intradimensional shift) made fewer errors than those for which the previously irrelevant dimension became relevant (shapes to lines or lines to shapes; extradimensional shift). These findings suggest that both humans and marmosets can learn to attend to the specific attributes or dimensions of a stimulus and use this information in visual discrimination learning.     

Judgment stability and pseudorecognition of random and patterned configurations

Thirty six simple patterns were judged as “random” or “patterned” by adult Ss. Category judgments were consistent whether Ss were told that 1/4, 1/2, or 3/4 of the patterns were random or if no proportion was specified. In a second experiment, Ss viewed a series of slides previously judged patterned followed by a recognition series with two additional patterned slides inserted in a series of otherwise random slides. Although slides were never labeled random or patterned, Ss made the most false recognitions for the two patterned slides. In another condition where random and patterned slides were reversed, most false recognitions were made for the two random slides. Both Gamer’s notion of hypothetical set size and an analysis of balanced elements fit the results, but the adequacy of both hypotheses can be questioned when applied to previous results with more complex patterns.     

Detecting conjunctions of color and form in parallel

Researchers have proposed that graphical efficacy may be determined, in part, by the nature of the perceptual interactions that exist between attributes used to create graphical displays. One extreme type of interaction isintegrality, in which two or more physical dimensions are represented as a single psychological dimension in the observer. An alternative type of interaction isconfigurality, in which a global emergent dimension is availableto the observer in addition to the component attributes. Thirteen stimulus sets, each composed of attributes commonly used in the design of graphs, were submitted to the performance-based diagnostics of integrality and configurality. Analyses suggest a continuum of configurality among the present stimulus sets, with little evidence for integral graphical attributes. The configural pattern of results was more common when two identical dimensions were paired (homogeneous stimuli) than when two different dimensions were paired (heterogeneous stimuli). However, there was no evidence that pairs of dimensions belonging to a single object (object integration) were any more configural than dimensions belonging to different objects. Object integration was, however, consistently related to inefficient performance in tasks requiring the filtering of one of two component dimensions.     

Interference in eyewitness and earwitness recognition

Face identification and voice identification were examined using a standard old/new recognition task in order to see whether seeing and hearing the target interfered with subsequent recognition. Participants studied either visual or audiovisual stimuli prior to a face recognition test, and studied either audio or audiovisual stimuli prior to a voice recognition test. Analysis of recognition performance revealed a greater ability to recognise faces than voices. More importantly, faces accompanying voices at study interfered with subsequent voice identification but voices accompanying faces at study did not interfere with subsequent face identification. These results are similar to those obtained in previous research using a lineup methodology, and are discussed with respect to the interference that can result when earwitnesses are also eyewitnesses. Copyright © 2010 John Wiley & Sons, Ltd.     

Shape Integration for Visual Object Recognition and Its Implication in Category-Specific Visual Agnosia

A series of experiments was conducted on a patient (ELM) with bilateral inferior temporal lobe damage and category-specific visual agnosia in order to specify the nature of his functional impairment. In Experiment 1, ELM performed a task of picture/word matching that used line drawings of fruits and vegetables as stimuli. The pattern of confusions exhibited by the patient suggested a failure in processing the full range of shape features necessary for the unique specification of the target relative to other structurally related items. This hypothesis of a shape integration impairment was tested and verified by subsequent visual recognition experiments (Experiments 2-4), which used synthetic stimuli with shapes precisely defined on the dimensions of elongation, curvature, and tapering. Furthermore, it was determined (Experiment 5) that the integration deficit is specific to the retrieval of shape knowledge from memory and does not affect the encoding of the properties of visual stimuli. It is argued that these findings have critical implications for cognitive theories of visual object recognition and for an interpretation of the visual function of the inferior temporal cortex. Finally, it was shown that the patient's deficit for structural knowledge integration is modulated by the semantic properties of the objects (Experiment 6), thereby demonstrating the applicability of the present findings to an explanation of category-specific visual agnosia.     

Limited translation invariance of human visual pattern recognition

Visual object recognition is considered to be largely translation invariant. An earlier study (Foster & Kahn, 1985), however, has indicated that recognition of complex novel stimuli is partially specific to location in the visual field: It is significantly easier to determine the identity of two briefly displayed random patterns if both stimuli are presented at the same, rather than at different, locations. In a series ofsame/different discrimination tasks, we characterize the processes underlying this “displacement effect”: Horizontal and vertical translations are equally effective in reducing performance. Making the task more difficult by increasing pattern similarity leads to even higher positional specificity. The displacement effect disappears after rotation or contrast reversal of the patterns, indicating that positional specificity depends on relatively low levels of processing. Control experiments rule out explanations that are independent of visual pattern memory, such as spatial attention, eye movements, or retinal afterimages. Positional specificity of recognition is found only forsame trials. Our results demonstrate that position invariance, a widely acknowledged property of the human visual system, is limited to specific experimental conditions. Normalization models involving mental shifts of an early visual representation or of a window of attention cannot easily account for these findings.     

Trade-off between memory for verbal items and their visual attributes.

Instructions to attend to the case and color in which words were presented led to improved retention of these visual attributes but depressed recognition performance. This trade-off between item and attribute memory occurred at three presentation rates (1.5, 5.5, and 10.5 sec/item), suggesting that visual attributes of verbal stimuli are rarely stored unless subjects expect that knowledge of physical form will be useful later. Visual attributes of high-imagery words were retained better than visual attributes of low imagery words by subjects instructed to attend to case and color, but not by subjects asked only to attend to word meaning. Implications of these findings for the hypothesis that visually presented verbal stimuli are stored as literal copies are discussed.