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PubMed1998

Similarity and the development of rules.

Similarity-based and rule-based accounts of cognition are often portrayed as opposing accounts. In this paper we suggest that in learning and development, the process of comparison can act as a bridge between similarity-based and rule-based processing. We suggest that comparison involves a process of structural alignment and mapping between two representations. This kind of structure-sensitive comparison process--which may be triggered either by experiential or symbolic juxtapositions--has a twofold significance for cognitive development. First, as a learning mechanism, comparison facilitates the grasp of structural commonalities and the abstraction of rules; and, second, as a mechanism for the application and extension of previously acquired knowledge, comparison processes facilitate the application of abstract knowledge to new instances.

Adult↗
PubMed1994

The neglected page.

Normal subjects bisect vertical lines above the true midpoint. We posited that the portion of the page farthest from the line or the page's geometric center, though not the focus of attention, would still engage attention. Therefore, subjects should make bisection errors in the direction of the distant portion or geometric center. We expected the greatest superior bisection errors to be made when lines were placed at the bottom of the page and the smallest errors to be made when the lines were placed at the top of the page. Ten young, normal subjects bisected vertical lines placed in 1 of 3 positions on a page (top, center, bottom) with the page located in 1 of 3 spatial locations (superior, middle, inferior). The results of our study were consistent with our predictions. Thus, although the page on which a line is bisected is often ignored, it is not neglected.

Adult↗
PubMed1990

Attentional limits on the perception and memory of visual information.

Attentional limits on perception and memory were measured by the decline in performance with increasing numbers of objects in a display. Multiple objects were presented to Ss who discriminated visual attributes. In a representative condition, 4 lines were briefly presented followed by a single line in 1 of the same locations. Ss were required to judge if the single line in the 2nd display was longer or shorter than the line in the corresponding location of the 1st display. The length difference threshold was calculated as a function of the number of objects. The difference thresholds doubled when the number of objects was increased from 1 to 4. This effect was generalized in several ways, and nonattentional explanations were ruled out. Further analyses showed that the attentional processes must share information from at least 4 objects and can be described by a simple model.

Adult↗
PubMed2000

The combined effects of plane disorientation and foreshortening on picture naming: one manipulation or two?

Objects disoriented in plane away from the upright and objects rotated in depth producing foreshortening are harder to identify than canonical views. In Experiments 1 and 2, participants named pictures of familiar objects. There was no interaction between plane and depth rotation effects on initial presentation or after practice. Experiment 3 was a dual-task psychological refractory period study. Participants classified a high-low tone with a speeded keypress and then named a canonical, plane-rotated, or foreshortened view of an object. Naming was slower when the picture was presented 50 ms after the tone compared with 800 ms after the tone. Plane rotation effects were reduced (but not eliminated) at the short tone-picture stimulus onset asynchrony, but foreshortening effects were not reduced. The results implicate an early, prebottleneck locus for some processes compensating for plane rotation and a subsequent bottleneck or postbottleneck locus for compensation for foreshortening.

Adult↗
PubMed1994

Influences of categorization on perceptual discrimination.

Four experiments investigated the influence of categorization training on perceptual discrimination. Ss were trained according to 1 of 4 different categorization regimes. Subsequent to category learning, Ss performed a Same-Different judgment task. Ss' sensitivities (d's) for discriminating between items that varied on category-(ir)relevant dimensions were measured. Evidence for acquired distinctiveness (increased perceptual sensitivity for items that are categorized differently) was obtained. One case of acquired equivalence (decreased perceptual sensitivity for items that are categorized together) was found for separable, but not integral, dimensions. Acquired equivalence within a categorization-relevant dimension was never found for either integral or separable dimensions. The relevance of the results for theories of perceptual learning, dimensional attention, categorical perception, and categorization are discussed.

Adult↗
PubMed1997

Pigeon same-different concept learning with multiple stimulus classes.

Two experiments examined the acquisition and transfer of a complex same-different discrimination by pigeons. With the use of a 2-alternative choice task, 5 pigeons were reinforced for discriminating odd-item Different displays in which a contrasting target ws present, from Same displays, in which all elements were identical. Four different types of same-different displays were concurrently tested. The display types differed in their configuration (texture vs. visual search organization), the nature of their elements (small and large colored shapes; pictures of birds, flowers, fish, and humans), and the processing demands required by their global-local element arrangement. Despite these differences, the pigeons learned to discriminate all 4 display types at the same rate and showed positive discrimination transfer to novel examples of each type, suggesting that a single generalized rule was used to discriminate all display types. These results provide some of the strongest evidence yet that pigeons, like many primates, can learn an abstract, visually mediated same-different concept.

Animals↗
PubMed1993

Occlusion and the distortion of alignment in three-dimensional space.

When observers are asked to align two rectangular stimuli oriented at 45 degrees to the visual axis there is a slight tendency to set the more distant stimulus closer to the eye than its true coplanar position. However, when a large rectangular surface is interpolated between the two oblique stimuli and the observer, errors of alignment become relatively much larger. The displacement caused by the interpolated stimulus occurs both when the display is viewed monocularly and when it is viewed binocularly. Reducing the obliquity of the rectangles results in smaller judgment errors and increasing obliquity increases errors; this is true with and without occlusion. The addition of texture elements to the surfaces of the rectangles reduces judgment errors significantly, but only under conditions of occlusion. It is possible that misalignments recorded for three-dimensional displays have something in common with the two-dimensional Poggendorff illusion.

Adult↗
PubMed2000

The effects of type and amount of pretraining on transfer in concept formation.

Two experiments were conducted to investigate the effects of 2 types of directed attention pretraining, a form of stimulus predifferentiation, on immediate- and delayed-transfer tasks in concept identification. In both experiments, the participants received either the "seeing-and-discriminating" or "seeing" technique of pretraining, except for those assigned to the control group. The participants received different amounts of pretraining. In the first experiment, participants were required to learn new concepts from the same category for the delayed-transfer task, whereas in the second experiment, the delayed-transfer task involved concepts from a different category. Among the major findings in both experiments are that the pretraining methods resulted in positive transfer on all transfer tasks. In general, the seeing-and-discriminating method yielded a more positive transfer than the seeing technique. Maximal positive transfer effects were found with a small number of trials. The implications of the findings for understanding the effectiveness of various training methods used for problem solving are discussed.

Adult↗
PubMed2004

Visual pattern recognition in Drosophila is invariant for retinal position.

Vision relies on constancy mechanisms. Yet, these are little understood, because they are difficult to investigate in freely moving organisms. One such mechanism, translation invariance, enables organisms to recognize visual patterns independent of the region of their visual field where they had originally seen them. Tethered flies (Drosophila melanogaster) in a flight simulator can recognize visual patterns. Because their eyes are fixed in space and patterns can be displayed in defined parts of their visual field, they can be tested for translation invariance. Here, we show that flies recognize patterns at retinal positions where the patterns had not been presented before.

Animals↗
PubMed1975

Perception.

Explore the source record for details and available documents.

Adaptation, Ocular↗
PubMed2002

Effects of a biocybernetic system on vigilance performance.

The present study was designed to determine whether a biocybernetic, adaptive system could enhance vigilance performance. Participants were asked to monitor the repetitive presentation of white bars on a computer screen for occasional increases in length. An index of task engagement was derived from participants' electroencephalographic (EEG) activity and was used to change the presentation rate of events among 3 values (6, 20, and 60 events/min). Under a negative feedback contingency, event rates increased if the engagement index decreased and, conversely, decreased if the index increased. Under positive feedback, the opposite contingency existed. Each experimental participant had a yoked control partner who received the same pattern of changes in event rates irrespective of his or her EEG activity. The results showed that better vigilance performance was obtained under negative feedback and that the performance of the yoked participants was similar to that of their experimental partners. These findings suggest that it may be possible to improve monitoring performance on critical activities such as air traffic control and radar and sonar operation through a pattern of event rate changes that do not rely on an operator's overt behavior.

Adolescent↗
PubMed1976

Information processing vs visual attention during incidental learning.

The relationship between attention and incidental learning during discrimination training was studied in 30 children, aged 10 to 11. A polymetric eye-movement recorder measured direct visual attention. Consistent with previous findings, recall of incidental stimuli was greatest during the initial and terminal stages of intentional learning. Contrary to previous explanations, however, visual attention to incidental stimuli was not related to training. While individual differences in attention to incidental stimuli were predictive of recall, attention to incidental stimuli was not related to level of training. Results suggested that changes in higher order information processing rather than direct visual attention were responsible for the curvilinear learning of incidental stimuli during intentional training.

Attention↗
PubMed1997

Contingent color aftereffects: reassessing old conclusions.

Although there is considerable evidence supporting an associative interpretation of contingent color aftereffects, there are data that appear inconsistent with this interpretation. New findings from seven experiments are presented indicating that, contrary to earlier claims, contingent color aftereffects are observed after induction with (1) single orthogonal black bars on colored backgrounds, (2) geometric forms, and (3) two orthogonal grids of the same color. The results of these experiments are relevant to an associative interpretation of contingent color aftereffects, as well as to assessing alternative interpretations of the phenomenon.

Adult↗