An empirical validation of the concept of coherence.

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2 microgenetic hypotheses were tested: perception would become more stable with an increase in duration of viewing; and this increase is different for form and for size. 100 plane figures, all combinations of 10 heights and 10 widths varying in increments of .01 in., constituted the stimulus set. They were presented singly as back-lighted figures in a completely dark surround. 7 male Ss had at least 20-20 vision uncorrected or with contact lens. There were 9 durations of viewing and 2 types of judgments: form, squares and rectangles, or size, large and small. Discrimination measures were computed and showed that Ss could discriminate form better than they could discriminate size. There was no significant effect of duration on either type of discrimination, nor was there any interaction between type of judgment and duration.

Section: Discussionmentioning

confidence: 99%

Effect of duration of viewing on form and size judgments.

Nesmith¹,

Rodwan²

1967

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“…In a previous study Rodwan (1964) showed that Ss produced larger F ratios when discriminating squares from rectangles than they did when discriminating large from small twodimension figures. The stimuli were 100 different plane figures.…”

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confidence: 89%

“…(For more detail on the LDF see Rodwan & Hake, 1964. ) The derived LDF was used to give a numerical value to each form used in this experiment; furthermore, the theoretical "form" axis derived from judgments of "square" vs. "rectangle" by Rodwan (1964) was also used to give another numerical value to each form. These two values were then correlated for each 5.…”

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confidence: 99%

Primacy of a form criterion in perceptual judgments.

Rodwan¹

1965

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Ss were each presented with 100 plane figures and told to assign them to 1 of 2 categories: "X" or "Y." These judgments were correlated with judgments of highly similar plane figures which had been assigned to "square" or "rectangle" categories. The mean correlation coefficient between the 2 judgments was .971. The 2 conclusions were: (a) heightwidth ratio is a prepotent cue and form is a primary judgment; (b) the use of the linear discriminant function (LDF) methodology is appropriate in discovering the subjective basis of perceptual judgments.

“…, and Rodwan and Hake (1964), and Rodwan (1964) have offered evidence for the argument that perception is a coherence-detecting system. Coherence detection is a technique used by communication receivers which enables them to separate signals from noise whenever a correlation can be established between some components of a noisy signal and a standard of comparison.…”

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confidence: 99%

Coherence detection: A basic mechanism.

Rodwan¹

1965

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This study was designed to test 2 hypotheses about perception: the subjective-standards hypothesis and a coherence-detection theory. The stimulus set consisted of 100 plane figures. 3 Ss were required to decide whether the stimulus was a square or a rectangle, or later whether it was a tall rectangle or a short rectangle. 10 other Ss were required to decide whether the stimulus was a tall rectangle, a square, or a short rectangle. The results showed that (a) Ss were reliable, (b) the basis for the judgments was identical, (c) a vertical-horizontal illusion exists, and (d) there was no significant difference between the mean subjective square and the mean subjective short rectangle. The inference drawn is that "square" is a response label and not a perceptual category.