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Biomedical subjects

P A Kolers

Publications and source records attributed to P A Kolers.

At least 19 recordsLinked to original sources
PubMed1985

Rhythms and responses.

Rhythms are fundamental to behavior, but the control mechanism for timed responses is not known. Many theorists have assumed that there is a central clock coordinating behavior in all sensory modalities and response modes. We tested this hypothesis using a rhythmic tapping task in which university undergraduates first attempted to synchronize responses with brief auditory, tactile, or visual stimuli and then continued to tap at the same rate on their own. Performance was most variable with visual stimuli and least variable with auditory stimuli. The detailed results suggest that performances are not based on a common clock, but, rather, different strategies are employed when the task is presented in different modalities. We reject the hypothesis of a single timing mechanism as controlling behavior and, in doing so, question the validity of information processing models that are formulated without regard to temporal relations among their conjectured processes.

Auditory Perception↗
PubMed1985

Size in the visual processing of faces and words.

We studied the influence of variations of stimulus size upon recognition of words and faces. Size played an important role in the recognition of faces but was irrelevant to the recognition of words, over a range of sizes. More detailed analysis revealed that although irrelevant to recognition, size of words was nevertheless encoded, with some consequences similar to those for recognition of faces. The results were interpreted in terms of stimulus-specific analyses, and this view was contrasted with other notions of mental representation.

Face↗
PubMed1985

Discontinuity in cognitive skill.

Skill at reading geometrically transformed text improves as a function of practice across pages. A belief in continuity of learning must suppose a proportionate improvement in skill within pages. We tested for continuity of learning by comparing performance within pages with performance between pages, varying timing of text presentation and quantity of text presented for the purpose. Reanalysis of some published data and three new experiments indicated that skill is acquired continuously as a function of practice but is expressed discontinuously. We conjecture that the expression of skill requires perceptual segregation of tasks into task units to which skill is transferred, whereas acquisition of competence occurs as a strict function of practice.

Adult↗
PubMed1984

Size and case of type as stimuli in reading.

The role of size and case of print have provoked a number of experiments in the recent past. One strongly argued position is that the reader abstracts a canonical representation from a string of letters that renders its variations irrelevant and then carries out recognition procedures on that abstraction. An alternate view argues that the reader proceeds by analyzing the print, taking account of its manifold physical attributes such as length of words, their orientation, shape, and the like. In the present experiments size and case were varied in several ways, and the task was also varied to include both silent reading and reading aloud. Clear evidence for shape-sensing operations was brought forward, but they were shown to be optional rather than obligatory processes, used when it served the reader's purpose to do so. However, it was also shown that such skills, normally useful, could be tricked into operating even when their presence hindered the reader's performance. The conclusion is drawn that reading goes forward in many ways at once rather than through an orderly sequence of operations, consistent with the reader's skills and the requirements of the task. Overarching theories of performance seem premature in the absence of detailed analysis of task components.

Cognition↗
PubMed1984

Color logic of apparent motion.

Two shapes of either the same or different color will seem to be in smooth apparent motion with like-colored mates, at proper conditions of flash timing and spacing. An experiment is reported in which the condition was tested for unlike-colored pairs, for example red-green alternated with green-red. The question of interest was how the visual system would resolve the disparity of color. An 'intelligent' solution would rotate the shapes in three dimensions. Like-colored and unlike-colored parts were found to move and transform similarly, however, the resolution being dependent more upon timing than upon color. The motion of intelligence as it might be applied to vision is discussed in light of these results.

Color Perception↗
PubMed1981

Sensory specificity of apparent motion.

Previous reports of intermodal apparent motion claim that the various senses contribute to or are under the guidance of a single synthesizing or organizing system, a common sense, and that under proper circumstances the separate heteromodal stimuli may be combined into a novel perceptual object. Our first experiment suggests that the term intermodal apparent motion has been misapplied in the past to one of the many idiosyncratic interpretations to which relatively meaningless patterns of heteromodal stimulation lend themselves. In our second experiment, we found that a properly timed visual stimulus can facilitate the perception of auditory apparent motion without its peculiarly auditory qualities of the moving percept. We find no evidence for a common or suprasensory organizing principle that integrates the separate visual and auditory stimuli.

Auditory Perception↗
PubMed1976

Pattern-analyzing memory.

College students reread text after an interval of 13 to 15 months more rapidly than they read new matter taken from the same sources. The results implicate a memory system at the level of pattern analysis that seems to be distinguishable from memory of syntactic and semantic features of text.

Adult↗
PubMed1975

Visual construction of color is digital.

When disparate shapes are flashed under the appropriate temporal and spatial conditions, the human visual system resolves their disparity smoothly and continuously. No equivalent supplementations are found for color, which the system resolves by abrupt transformation. Shape and color reveal themselves, contrary to some modern theorizing, as properties handled in different ways by the visual nervous system, continuous or analog for shape, abrupt or digital for color.

Color Perception↗