Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Perceptual Closure”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13Linked to original sources
PubMed1993

Time course of object identification: evidence for a global-to-local contingency.

A time course contingency is the modification of later phases of object recognition contingent upon stimulus information extracted earlier in processing. It can increase the efficiency of later processing and reduce computational burdens. This idea was instantiated within a global-to-local model and supported in 4 integration priming experiments, in which primes and target objects were presented briefly and then masked. In Experiment 1-3, global and coarse-grained common-feature primes presented early in processing facilitated discriminations between similarly shaped objects, even though they provided no discrimination-relevant information. In Experiment 4, global primes were more effective than local primes early in processing, whereas local primes were more effective than global primes late in processing.

Adult↗
PubMed1995

What causes the face inversion effect?

What is it about the way faces are represented by the visual system that makes them so much harder to recognize when inverted? The authors tested the hypothesis that the "face inversion" effect results from the use of holistic shape representations. This suggests that the susceptibility of nonface patterns to inversion should be a function of their degree of part decomposition. In Experiment 1 this was tested and confirmed with dot patterns in which the degree of part decomposition was manipulated by grouping and segregation on the basis of dot color. The hypothesis also predicted that the face inversion effect can be eliminated with face stimuli if participants are induced to recognize the faces in terms of their component parts. In Experiment 2 this was tested and confirmed with whole, intact faces, in which the degree of part decomposition was manipulated by allowing participants to study them, initially, in either whole, intact versions or versions with parts presented separately.

Adult↗
PubMed2002

Unraveling mechanisms for expert object recognition: bridging brain activity and behavior.

Behavioral sensitivity to object transformations and the response to novel objects (Greebles) in the fusiform face area (FFA) was measured several times during expertise training. Sensitivity to 3 transformations increased with expertise: (a) configural changes in which halves of objects were misaligned, (b) configural changes in which some of the object parts were moved, and (c) the substitution of an object part with a part from a different object. The authors found that holistic-configural effects can arise from object representations that are differentiated in terms of features or parts. Moreover, a holistic-inclusive effect was correlated with changes in the right FFA. Face recognition may not be unique in its reliance on holistic processing, measured in terms of both behavior and brain activation.

Brain↗
PubMed1978

Perceptual processes that may create stick figures and balance.

A series of experiments looked at the pattern of dot placements created when people individually placed a single dot inside empty outline figures. The superimposed results were found to compare better with the predictions of Blum's grassfire model than with a size-constancy process. The pattern of superimposed dots conformed to the stick figure of the outlined contours. A perceptual model based on spatial harmonic analysis of complex visual scenes is offered as an explanation for the pattern of results.

Cognition↗
PubMed1978

Studies of visual synthesis: integration of fragments into forms.

On each of a series of trials, subjects indicated whether two sequential visual forms were the same or different. The first form was presented on some trials as a whole within a square frame and on others in fragments--with its perimeter distributed over two or three frames. The subject was instructed to visualize the first form as a whole in any case, and study time (ST) for the form was recorded. The same/different reaction time (RT) for the second, test, form (always presented in one frame) was also recorded. Experiment 1 revealed that variables affecting ST had little effect on RT and indicated that subjects can process fragments of forms in parallel. Experiment 2 demonstrated that the representation encoded from fragments differed from one generated from long-term memory. Whereas the first experiments used wholes as test stimuli, in Experiments 3 and 4 on some trials, fragments were used. In Experiment 3, RT was facilitated when a test fragment coincided with an intact fragment of the first stimulus. This indicated that first stimuli were not encoded as complete wholes. In Experiment 4, irregular forms were used as stimuli, and the RT data departed from predictions of the parallel model. Taken as a whole, the results place constraints on the codes produced by constructive processes acting to synthesize fragments into wholes.

Discrimination, Psychological↗
PubMed1978

The seeing-more-than-is-there phenomenon: implications for the locus of iconic storage.

When a target figure is moved back and forth behind a window cut in an opaque screen, more of the figure is seen at a given instant than is physically present. This finding implies that the information presented at one instant is stored in iconic form so that it can be integrated with information presented at a slightly later instant. Two experiments explored the illusion and showed that it can be readily demonstrated under a variety of conditions. A third experiment indicated that it can occur in the absence of appreciable eye movements. This latter finding, together with various supporting argument, is taken as evidence against an explanation of the illusion in terms of the target image being painted across the retina. Rather, it appears that successive sections of the target item are projected onto the same retinal sector. It is difficult to understand how simple photoreceptors can simultaneously retain information presented at one instant and register information presented at a subsequent time without two pieces of information being fused. Therefore, it is concluded that the iconic storage implied by the illusion occurs at a level more central than that of the retinal receptors.

Eye Movements↗
PubMed1981

Detection of symmetry.

The time to detect symmetries in square field patterns was measured. The same relationships among mean detection times for different symmetries was found in both well-practiced and naive subjects. When the task was to detect any symmetry, detection times were faster for multiply symmetry was faster than diagonal, singly symmetric ones. Horizontal-vertical symmetry was faster than diagonal, which was faster than centric. When the task was to detect specific symmetry, that is, vertical, horizontal,diagonal, or centric only, detection times were faster again for multiply symmetric patterns, suggesting that "irrelevant" symmetry facilitates performance. Errors and response times indicate that certain symmetries are more difficult to reject than others, depending on the type of symmetry to be detected. Thus, the results suggest interference effects arising from certain symmetries. The data are best accounted for by a model in which symmetry is encoded integrally. When decoding is required by the task, as in detection tasks, the observer performs a serial hierarchical decomposition of the code.U

Discrimination Learning↗
PubMed2000

Overt and covert identification of fragmented objects inferred from performance and electrophysiological measures.

The authors investigated visual processing leading to object identification by manipulating the number of fragments and nature of the study. During the study, participants either named or drew objects in Experiment 1 and drew them all in Experiment 2. During the test, participants made an identification judgment at each of 6 different fragmentation levels for studied and new objects. Fewer fragments were needed to identify studied than unstudied objects. Reaction times were faster for studied than unstudied objects both at identification and at the preceding level. Event-related brain potentials (ERPs) to unidentified objects were characterized by a late negativity in contrast to a positivity to identified objects. ERPs to studied but not to new objects contained a smaller and later version of the identification positivity at level just prior to identification, which was not due to differential response confidence. Much covert visual analysis and even object identification may precede overt identification, depending on the nature of prior experience.

Adult↗
PubMed1992

Discrimination of contour-deleted images by pigeons.

Three experiments attempted to determine which properties of pictorial representations of objects control their discrimination by pigeons. A particular focus was whether the representation mediating such discriminations could be described by the simple viewpoint-invariant primitive volumes of Biederman's (1987) recognition-by-components theory of object recognition or by Cerella's (1990) particulate features. In all 3 experiments, pigeons were first trained to discriminate drawings of 4 stimulus objects with half of the contour deleted but with the component geons postulated by Biederman's theory recoverable. Discrimination accuracy was then compared for test items containing the original particulate features, affording the retrieval of the original component geons, or having neither of these properties of the training stimuli. Although response accuracy was significantly greater when the component geons of the original objects were retrievable, measurable control over recognition by the particulate features of the objects and by their specific locations was also found. The results are consistent with the idea of component geon recognition as one of the important factors in object discrimination.

Animals↗
PubMed1994

Dissociations among implicit and explicit memory tasks: the role of stimulus similarity.

This article compares the effect of picture fragmentation level at study on performance on a variety of implicit and explicit memory tests. Consistent with previous research, a moderately fragmented study picture produced the most learning on the implicit memory task of picture fragment completion (Experiment 1) and speeded picture identification (Experiment 4). In contrast, an intact study picture produced the most learning on the implicit memory task of naming intact pictures (Experiment 3). These results suggest that performance on 2 implicit memory tasks can be dissociated by differences in visual similarity between the study and test forms of a stimulus. More surprising, parallel effects were observed in recognition memory. Recognition memory was best when fragmentation levels of the study and test pictures matched (Experiment 2) or were comparable (Experiment 1). In contrast to many results in the literature, recognition memory was acutely sensitive to surface form differences. We discuss the results in terms of 2 types of study-test similarity-stimulus similarity and process similarity.

Adolescent↗
PubMed1996

Contrast and illumination effects on explicit and implicit measures of memory.

The present study examined the effect of changing the contrast polarity and illumination of objects on explicit (episodic recognition) and implicit (fragment naming or object-nonobject decision) memory tasks. Changes in contrast polarity of line drawings of objects did not affect priming on fragment naming or on object-nonobject decision tasks but adversely affected recognition judgments. Similarly, changes in illumination did not affect priming on the object-nonobject decision task but adversely affected recognition memory. Together, the results suggest that implicit measures tap abstract descriptions of object structure useful for the purposes of object identification, whereas recognition memory taps descriptions that integrate shape information with lower level perceptual information. It is argued that lower level perceptual information influences episodic recognition because it provides a cue to the spatiotemporal context within which the prior encounter with the object occurred.

Adult↗
PubMed1988

Initiating the formalization of theories of cognitive aging.

Although the relevant knowledge base is still impoverished, the time may be appropriate to attempt to develop and investigate formal models of cognitive aging that incorporate explicit mechanisms to account for age differences frequently observed in measures of cognitive functioning. An initial model based on an associative network metaphor is described, in which age declines in fluid or process aspects of cognition are attributed to a reduction in either the number of simultaneously active nodes, the maximum allowable activation, or the rate of propagating activation between nodes. Results from a computer simulation are consistent at a first level of approximation with many cognitive aging phenomena, and the model is shown to provide a plausible account of age differences in an area that has previously resisted explanation. Although this particular model is only one of many that could be formulated at the present time, it is argued that more rapid progress in theoretical understanding of cognitive aging phenomena will be achieved by attempting to specify one's assumptions and hypotheses in a formal and explicit manner.

Aged↗
PubMed1989

Structural and operational capacities in integrative spatial ability.

Four experiments were conducted to explore a distinction between structural capacity, the maximum number of informational units that can be temporarily stored, and operational capacity, the number of processing operations that can be executed while simultaneously preserving the products of earlier processing. The results, from a synthesis task requiring the integration of successively presented line segments into a composite stimulus, revealed that there were little or no age differences in structural capacity but large age differences favoring young adults in operational capacity. An attempt was also made to determine how much earlier information was available after each additional processing operation, but equivocal results precluded a definitive conclusion about the exact nature of the age differences in operational capacity.

Adult↗
PubMed1991

Effects of aging on priming and skill learning.

This study examined the effects of aging on 2 kinds of implicit memory; repetition priming and skill learning. In Experiment 1, older adults showed less improvement in the skill of reading inverted words than did young adults, but priming performance did not differ for the 2 age groups. Similarly, in Experiment 2, in a partial-word identification task, skill learning was observed only for young adults, whereas there was no age difference in priming. Experiments 1a and 2a, however, showed that when older adults were presented with more perceptual information than were young adults, the age deficit in skill learning was eliminated. These results indicate that skill learning is impaired under data-limited conditions, whereas priming is unaffected under these conditions. It is proposed that the age deficit in skill learning is related to a deficit in perceptual organization and reorganization.

Adolescent↗
PubMed2006

Visual complexity: a review.

The idea of visual complexity, the history of its measurement, and its implications for behavior are reviewed, starting with structuralism and Gestalt psychology at the beginning of the 20th century and ending with visual complexity theory, perceptual learning theory, and neural circuit theory at the beginning of the 21st. Evidence is drawn from research on single forms, form and texture arrays and visual displays. Form complexity and form probability are shown to be linked through their reciprocal relationship in complexity theory, which is in turn shown to be consistent with recent developments in perceptual learning and neural circuit theory. Directions for further research are suggested.

Humans↗
PubMed2005

3-d interpolation in object perception: evidence from an objective performance paradigm.

Object perception requires interpolation processes that connect visible regions despite spatial gaps. Some research has suggested that interpolation may be a 3-D process, but objective performance data and evidence about the conditions leading to interpolation are needed. The authors developed an objective performance paradigm for testing 3-D interpolation and tested a new theory of 3-D contour interpolation, termed 3-D relatability. The theory indicates for a given edge which orientations and positions of other edges in space may be connected to it by interpolation. Results of 5 experiments showed that processing of orientation relations in 3-D relatable displays was superior to processing in 3-D nonrelatable displays and that these effects depended on object formation. 3-D interpolation and 3-D relatabilty are discussed in terms of their implications for computational and neural models of object perception, which have typically been based on 2-D-orientation-sensitive units.

Analysis of Variance↗
PubMed2006

On the surprising salience of curvature in grouping by proximity.

The authors conducted 3 experiments to explore the roles of curvature, density, and relative proximity in the perceptual organization of ambiguous dot patterns. To this end, they developed a new family of regular dot patterns that tend to be perceptually grouped into parallel contours, dot-sampled structured grids (DSGs). DSGs are similar to the dot lattices used to study grouping by proximity, except that only one of the potential organizations is rectilinear; the others are curvilinear. The authors used the method of M. Kubovy and J. Wagemans (1995) to study grouping by proximity in DSGs. They found that in the competition between the most likely organizations, one rectilinear and the other curvilinear, the latter is more salient. This phenomenon cannot be explained by contemporary accounts of grouping by proximity or contour integration.

Adult↗
PubMed2006

Picture-object recognition in pigeons: evidence of representational insight in a visual categorization task using a complementary information procedure.

Success in tasks requiring categorization of pictorial stimuli does not prove that a subject understands what the pictures stand for. The ability to achieve representational insight is by no means a trivial one because it exceeds mere detection of 2-D features present in both the pictorial images and their referents. So far, evidence for such an ability in nonhuman species is weak and inconclusive. Here, the authors report evidence of representational insight in pigeons. After being trained on pictures of incomplete human figures, the birds responded significantly more to pictures of the previously missing parts than to nonrepresentative stimuli, which demonstrates that they actually recognized the pictures' representational content.

Animals↗