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Biomedical subjects

P J Locher

Publications and source records attributed to P J Locher.

11 recordsLinked to original sources
PubMed2001

The influence of presentation format and viewer training in the visual arts on the perception of pictorial and aesthetic qualities of paintings.

The comparability of viewers' responses to slide-projected and computer-generated images of nine paintings by renowned artists to those obtained from individuals experiencing the originals in the galleries of the New York Metropolitan Museum of Art was investigated. The influence of training in the visual arts upon evaluative judgments made under the three presentation formats was also assessed. Specifically, art-trained and untrained participants in each format condition rated each artwork on sixteen measures of physical and structural characteristics, novelty of content, and aesthetic qualities. Analyses revealed significant differences in the judged hedonic value of the originals as contrasted with the two types of reproduction, whereas trained and untrained participants' evaluations of the pictorial qualities of the artworks were comparable across presentation formats. Findings are discussed in terms of a facsimile-accommodation hypothesis proposed by the authors.

Adult↗
PubMed1999

An empirical evaluation of the visual rightness theory of pictorial composition.

This research tested the visual rightness theory of pictorial composition's assertion that the induced organizational structure of a visually right (i.e., "good") design is perceptually salient and judged superior by anyone viewing it regardless of his or her training in the visual arts. Stimuli for Experiments 1 and 2 consisted of 16 reproductions of paintings by renowned artists and an experimentally reconstructed less-well-organized version of each art stimulus. It was found that design professionals (Experiment 2) were significantly more successful at detecting the original versions than were participants untrained in the visual arts (Experiment 1) (hit rates = 64% and 55%, respectively). In Experiment 3 participants replaced a major structural element removed from each of six pictures of the stimulus set at the location where they thought it appears in the original. A significant number of untrained participants and those with training in design theory were in agreement as to the location of each element within its pictorial field; the location chosen conformed to its compositional structure but not its actual location in the original. Findings demonstrate that the ability to detect the induced structural skeleton of a painting resulting from a visually right design does not require expert knowledge of design principles whereas the ability to discriminate between several articulation possibilities of the same composition does require formal training.

Adult↗
PubMed1993

Effects of element type and spatial grouping on symmetry detection.

The influence of local and global attributes of symmetric patterns on the perceptual salience of symmetry was investigated. After tachistoscopic viewing, subjects discriminated between symmetric and either random patterns (experiment 1) or their perturbed counterparts (experiment 2) created by replacing one third of the mirror element-pairs of symmetric stimuli with 'random' elements. In general, it was found that perceptibility of symmetry, measured by response time and detection accuracy, was not influenced in a consistent way by type of pattern element (dots or line segments oriented vertically, horizontally, obliquely, or in all three orientations about the symmetry axis). Nor did axis orientation (vertical, horizontal, oblique), advance knowledge of axis orientation, practice effects, or subject sophistication differentially affect detection. A highly salient global percept of symmetry emerged, on the other hand, when elements were clustered together within a pattern, or grouped in symmetric pairs along a single symmetry axis or two orthogonal axes. Results suggest that mirror symmetry is detected preattentively, presumably by some kind of integral code which emerges from the interaction between display elements and the way they are organized spatially. It is proposed that symmetry is coded and signalled by the same spatial grouping processes as those responsible for construction of the full primal sketch.

Attention↗
PubMed1983

Visual exploratory activity of hemiplegic patients viewing the motor-free visual perception test.

Eye movements of adult hemiplegics (11 right- and 9 left-brain-damaged patients) and 11 nonimpaired controls were recorded as they viewed selected cards of the Motor-free Visual Perception Test. The major finding was that neither group of patients exhibited an asymmetry of visual exploration (unilateral visual neglect) as they viewed the cards. Their scanning strategies were, however, unsystematic and irregular. In addition, both groups of patients scanned the cards longer and made more errors than controls. Use of the Motor-free Visual Perception Test as an appropriate measure for the general assessment of visual-perceptual processing abilities of adult brain-damaged patients who lack severe clinical manifestations of neglect is discussed.

Brain Damage, Chronic↗
PubMed1982

Influence of vision on haptic encoding processes.

Sighted subjects (n = 15) assembled 6-piece jigsaw puzzles under four conditions of visual-haptic perception which both separated these perceptual systems and required the simultaneous use of vision and touch. The time required and haptic scanning strategies used to assemble the puzzles in each of the four conditions were examined to determine the influence of type of visual involvement upon haptic encoding processes and the degree to which the visual and haptic systems are linked. Results indicate that a cognitive component is involved during visual-tactual form perception which affects how the perceptual modalities work together and how information is selected, encoded, and processed. When vision and touch were used simultaneously to examine the same stimulus, and visual information was adequate for responding, vision dominated touch. However, in conditions of visual-haptic perception in which visual input was inadequate for responding or when haptic perception was independent of vision, subjects relied upon a form of information which was specifically tactual in nature and independent of visual or verbal recoding.

Discrimination Learning↗
PubMed1979

Role of extended perceptual experience upon haptic perception of nonrepresentational shapes.

The influence of amount and type of exploratory activity upon 3 male and 5 female undergraduates' ability to detect the symmaterical or asymmetrical characteristics of individually presented plastic nonrepresentational shapes was examined. A decrease in scanning time and number of identification errors between the first and fourth days of testing indicates that extended perceptual experience plays a major role in the efficient pick-up and utilization of haptic information. A signal-detection analysis demonstrated that the use of a simultaneous-apprehension scanning strategy resulted in greater sensitivity to asymmetrical shapes than did the use of a simultaneous-apprehension scan. The data support the hypothesis that experience, the form parameter of symmetry, and the type of scanning strategy used to explore a stimulus function together to influence haptic perception of nonrepresentational shapes.

Female↗
PubMed1977

Global detection of symmetry.

Two experimental approaches examined observers' ability to characterize shape symmetry based upon the information obtained within a single fixation. Exp. I tested observers' ability to discriminate among three levels of symmetry on the basis of a 25-msec. presentation. Results indicated that identification accuracy was higher for symmetrical and asymmetrical shapes than for mixed shapes, which contained both symmetrical and asymmetrical components. Exp. II tested observers' ability to detect a given level of symmetry by means of a signal-detection approach. Symmetrical shapes were detected better than asymmetrical shapes. Detectability of mixed shapes was lower than that for both symmetrical and asymmetrical shapes. The results of Exps. I and II demonstrate that observers can characterize shape symmetry on the basis of information available within a single fixation. The data are supportive of the hypothesis that a global response to the over-all configuration of the shape serves to facilitate form perception.

Discrimination, Psychological↗