Recognizing novel views of three-dimensional objects.

Examined how novel, 3-dimensional shapes are represented in long-term memory and how this might be differentially affected by monocular and binocular viewing in 3 experiments with a total of 141 undergraduates. Exp 1 established that slide projections of the novel objects could be recognized readily if seen in the same orientation as seen during learning. Exps 2 and 3 examined generalization to novel depth rotations of the objects. Results are consistent with a growing body of recent research showing that, at least under certain conditions, the visual system stores viewpoint-specific representations of objects. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Seeing two sides at once: Effects of viewpoint and object structure on recognizing three-dimensional objects.

Five experiments demonstrated that adults can identify certain novel views of 3-dimensional model objects on the basis of knowledge of a single perspective. Geometrically irregular contour (wire) and surface (clay) objects and geometrically regular surface (pipe) objects were accurately recognized when rotated 180° about the vertical (y) axis. However, recognition accuracy was poor for all types of objects when rotated around the y-axis by 90°. Likewise, more subtle rotations in depth (i.e., 30° and 60°) induced decreases in recognition of both contour and surface objects. These results suggest that accurate recognition of objects rotated in depth by 180° may be achieved through use of information in objects' 2-dimensional bounding contours, the shapes of which remain invariant over flips in depth. Consistent with this interpretation, a final study showed that even slight rotations away from 180° cause precipitous drops in recognition accuracy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual attention and objects: Evidence for hierarchical coding of location.

In 5 experiments, it was found that judging the relative location of 2 contours was more difficult when they belonged to 2 objects rather than 1. This was observed even when the 1- and 2-object displays were physically identical, with perceptual set determining how many objects they were seen to contain. Such a 2-object cost is consistent with object-based views of attention and with a hierarchical scheme for position coding, whereby object parts are located relative to the position of their parent object. In further experiments, it was shown that in accord with this hierarchical scheme, the relative location of objects could disrupt judgments of the relative location of object parts, but the reverse did not occur. This was found even when the relative position of the parts could be judged more quickly than that of the objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recognizing objects seen from novel viewpoints: Effects of view similarity and time.

View combination refers to a process that allows generalization to novel views of an object by the combination of object views represented in memory. The present experiments examined whether the perceived similarity between views or the temporal separation of views poses constraints on the view combination process. The results indicated that, although similar views are mapped onto the same object more easily than dissimilar views, dissimilar views, when experienced contiguously in time, produce greater generalization after view combination than similar views. These findings suggest that although the mapping of dissimilar views to the same object is difficult, exposure to temporally contiguous dissimilar views produces better generalization than does exposure to similar views, presumably because they provide more structural information about the object. However, view combination appears to be constrained to views experienced contiguously in time. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recognition times of different views of 56 depth-rotated objects: a note concerning Verfaillie and Boutsen (1995)

The present study examines the effect of the goodness of view on the minimal exposure time required to recognize depth-rotated objects. In a previous study, Verfaillie and Boutsen (1995) derived scales of goodness of view, using a new corpus of images of depth-rotated objects. In the present experiment, a subset of this corpus (five views of 56 objects) is used to determine the recognition exposure time for each view, by increasing exposure time across successive presentations until the object is recognized. The results indicate that, for two thirds of the objects, good views are recognized more frequently and have lower recognition exposure times than bad views.     

Stimulus-driven attentional capture: Evidence from equiluminant visual objects.

Previous work has shown that abrupt visual onsets capture attention. Possible mechanisms for this phenomenon include (1) luminance-change detection system and (2) a mechanism that detects the appearance of new perceptual objects. Exps 1 and 2 revealed that attention is captured in visual search by the appearance of a new perceptual object even when the object is equiluminant with its background and thus exhibits no luminance change when it appears. Exp 3 showed that a highly salient luminance increment alone is not sufficient to capture attention. These findings suggest that attentional capture is mediated by a mechanism that detects the appearance of new perceptual objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recognizing identical versus similar categorically related common objects: Further evidence for degraded gist representations in amnesia.

Studies have shown lower false recognition of semantically related lure words in patients with global amnesia than in matched controls. This pattern has been interpreted as suggesting that medial temporal and diencephalic structures that are damaged in amnesia and that contribute to veridical memory also contribute to false recognition. It has been argued that whereas controls form and retain a well-organized representation of the semantic gist of studied items, patients with amnesia can retain only a degraded gist representation. However, these studies are subject to an alternative interpretation involving greater source confusions in controls. The authors used a categorized-pictures paradigm to test recognition under conditions in which source confusions were unlikely to occur. Relative to controls, patients with amnesia showed reduced false recognition of categorically related pictorial lures, thereby supporting the notion of degraded gist representations in amnesia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mental rotation of representations of two-dimensional and three-dimensional objects.

Empirical and theoretical considerations suggest that representations of three-dimensional objects should be more difficult to rotate mentally than representations of two-dimensional objects. In this study, subjects were asked to make mirror-normal decisions with stimuli that differed in perceived dimensionality and in angle of rotation in the image plane. In a series of four experiments, the time to make mirror-normal decisions increased with increased orientation discrepancy between the stimuli, as found previously in the literature. In every experiment, however, response times were smaller for representations of two-dimensional shapes than for representations of three-dimensional shapes when the stimuli being compared were presented with a large angular discrepancy. Whereas response times increased linearly with orientation when representations of three-dimensional shapes were rotated, the increase in response time for representations of two-dimensional shapes was generally nonlinear. Overall, the evidence suggests that representations of three-dimensional shapes are mentally rotated at the same rate as representations of two-dimensional shapes for angles of rotation between 0° and 60°. For larger angles of rotation, however, the rate of mental rotation is greater for representations of two-dimensional shapes than for representations of three-dimensional shapes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perception of partly occluded objects and illusory figures: Evidence for an identity hypothesis.

Three experiments tested the hypothesis that perception of partly occluded figures (POFs) and illusory figures (IFs) derive from a single visual interpolation process. In each, 2 magnitude estimation tasks were used. One assessed perceived unity of visible parts of POFs; the other perceived clarity of edges on perceived unity and clarity. Exp 3 used randomly generated displays to test whether edge relations sampled at random would exert the same effects on POFs and IFs. All studies showed nearly perfect correlations between perceived unity and perceived edge clarity, when the physically specified parts of the figures were identical. The specific conditions under which edges are interpolated fit well with predictions of a recent theory (P. J. Kellman and T. F. Shipley, 1991). These results suggest that a single unit-formation process underlies "modal" and "amodal" completion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of distinctive parts on recognition of depth-rotated objects by pigeons (Columba livia) and humans.

To explore whether effects observed in human object recognition represent fundamental properties of visual perception that are general across species, the authors trained pigeons (Columba livia) and humans to discriminate between pictures of 3-dimensional objects that differed in shape. Novel pictures of the depth-rotated objects were then tested for recognition. Across conditions, the object pairs contained either 0, 1, 3, or 5 distinctive pails. Pigeons showed viewpoint dependence in all object-part conditions, and their performance declined systematically with degree of rotation from the nearest training view. Humans showed viewpoint invariance for novel rotations between the training views but viewpoint dependence for novel rotations outside the training views. For humans, but not pigeons, viewpoint dependence was weakest in the 1-part condition. The authors discuss the results in terms of structural and multiple-view models of object recognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceiving spatially inseparable objects: Evidence for feature-based object selection not mediated by location.

In 4 experiments, stimulus elements were arranged into an LED-like array, and letters were defined within the array by feature similarity between the elements with respect to color and form. These stimuli allowed the display of a target and a distractor letter simultaneously at the same location. They were spatially inseparable but could be separated in feature space. Participants had to identify the letter on a prespecified feature dimension (color or form). As a result, the distractors produced specific compatibility effects. This showed that nontarget features could not be ignored at an early stage (i.e., that color and form were processed automatically and in parallel up to a high stage). The target was selected from the resulting objects according to the prespecified feature dimension. Results demonstrate that object selection is possible without selecting absolute spatial arrays. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mental representation of three-dimensional objects in visual problem solving and recognition.

Ss inspected sets of flat, separated orthographic projections of surfaces of potential 3-dimensional objects. After solving problems based on these orthographic views, Ss discriminated between isometric views of the same objects and drawings of distractor structures. Recognition of the isometrics, which had never been shown during the problem-solving phase of the experiment, was excellent. In addition, recognition of isometrics corresponding to problems that had been solved correctly when presented in orthographic form was significantly superior to recognition of isometrics based on problems solved incorrectly. In Exp 2, conditions were included in which either orthographic or isometric views functioned as problem solving or recognition displays. Only in the case of orthographic problem solving followed by isometric recognition (Exp 1) was the superiority of recognition for correctly solved problems over incorrectly solved problems obtained. The pattern of results suggests that viewers construct mental representations embodying structural information about integrated, 3-dimensional objects when asked to reason about flat, disconnected projections. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Mood and memory under natural conditions: Evidence for mood incongruent recall.

The effect of mood on memory was studied under natural conditions in 2 field quasi-experiments. In both, Ss in happy moods recalled autobiographical memories that were more negative than were memories recalled by subjects in bad moods, a phenomenon termed mood incongruent recall. Three subsequent laboratory experiments are reported that suggest that mood incongruent recall is a reliable phenomenon, occurring when subjects are unaware that their moods are relevant to the experiment. Mood incongruent recall is hypothesized to be related to mood regulation. The implications of these findings for the relation between mood and memory, for mood congruent recall, for laboratory mood inductions, and for self-regulation of mood and depression are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An investigation of sex differences in spatial ability: Mental rotation of three-dimensional objects.

Presented 2-dimensional computer-generated representations of 3-dimensional objects in pairs to 20 male and 20 female right-handed undergraduates. Ss were given 15 sec to make a same-different judgment of the objects, one of which was rotated 0°, 40°, 80°, 120°, or 160° from the other. Ss were also assessed on 2 standard spatial ability tests (the Spatial Relations subtest of the Differential Aptitude Tests, Form L, and the Standardized Road-Map Test of Direction Sense) and a verbal-imagery questionnaire. Analyses of the data showed that men were more accurate than women, and that the slope of the function relating response time to degree of rotation was steeper in women. There was a significant linear relation between performance and the degree of rotation. Rate of rotation and accuracy correlated with the other tests of spatial ability. Response time slope correlated with imagery in men but not in women, suggesting that frequent use of visual imagery was related to mental rotation rate in men, but not in women. There were no clear relations between performance and the strategy Ss professed to use in doing the mental rotation. (French summary) (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recognition of aspect-dependent three-dimensional objects by an echolocating Atlantic bottlenose dolphin.

We examined the ability of a bottlenose dolphin (Tursiops truncatus) to recognize aspect-dependent objects using echolocation. An aspect-dependent object such as a cube produces acoustically different echoes at different angles relative to the echolocation signal. The dolphin recognized the objects even though the objects were free to rotate and sway. A linear discriminant analysis and nearest centroid classifier could classify the objects using average amplitude, center frequency, and bandwidth of object echoes. The results show that dolphins can use varying acoustic properties to recognize constant objects and suggest that aspect-independent representations may be formed by combining information gleaned from multiple echoes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)