Paul A. Kolers

Procedures of Mind.

The prevailing metaphor for studies of learning and memory emphasizes the acquisition, storage, and retrieval of “information”; within this framework, mind is often treated as if it were a physical object and information similarly is assumed to have physicalistic properties. Evidence that supports a more process-oriented view of information processing is offered. Mind is described in terms of skill in manipulating symbols and the notion of skills is shown to provide a useful framework for accounting for significant aspects of cognitive processes. Evidence supporting the procedural view includes studies that show that the means of acquisition of information form part of its representation in mind, that recognition varies with the similarity of procedures in acquisition and test, and that transfer between tasks varies with the degree of correspondence of underlying procedures.

Reading a Year Later.

Two sets of measurements evaluated performance on typographically inverted text that students had learned to read 13 to IS months earlier. In one set, speed of reading was compared for pages read for the first and second times. Reread pages were read more quickly, thereby revealing an exceptional degree of memory at the pattern-analyzing level. In the second set of measurements, the readers classified the pages as to occasion of reading. Comparing the two sets of measurements showed that different aspects of memory were measured by the different tests, and they were not well correlated. Performance is accounted for in terms of encoding operations directed at the linguistic patterns, in contrast to the more familiar notion of manipulating semantic representations.

Memorial consequences of automatized encoding.

The first experiment tracked the acquisition of skilled reading as college students read as many as 160 pages of geometrically inverted text. The logarithm of reading time decreased linearly as a function of the logarithm of amount of practice, and performance on inverted text approached performance on normal text remarkably rapidly. The second experiment assessed the consequence for memory of skill at reading. Students unpracticed at reading inverted text remembered for lengthy intervals the inverted sentences they read; when students acquired skill with the typography, their memory for inverted sentences was poorer. The results are interpreted in terms that emphasize an operational basis to memory—pattern-analyzing procedures rather than conscious contents. This view is contrasted with three other accounts of recognition.

Shape and color in apparent motion.

Abstract The resolution of disparity between two shapes that are flashed at appropriate spatial and temporal separations is smooth and continuous. The present inquiry was directed at the corresponding resolution of disparate colors. Presented with a red and a green, say, the visual system could desaturate one to a neutral point and then saturate the other from that point; or it could allow the red to change through orange and yellow to green, for example. Neither of these occurred. No intermediaries were found between two discriminably different colors: rather, one changed abruptly to the other. The abrupt change of color occurred even when the stimuli were doubly disparate, in shape and color. Then the shape was seen to change gradually, the color to change abruptly, but color was always seen filling in the contours of the apparently changing shape.

Readability of text scrolled on visual display terminals as a function of window size

Readability of text scrolled on visual display terminals was studied as a function of three different line lengths, two different character densities, and five different window heights (either 1, 2, 3, 4, or 20 lines). All three variables significantly affected reading rate, but to markedly different extents. Lines of full and two-thirds screen width were read, on average, 25% faster than lines of one-third screen width. Text appearing at a density of 80 characters per line was read 30% faster than text in a format of 40 characters per line. Text appearing in windows four lines high was read as efficiently as text in 20-line window, and text in one- or two-line windows was read only 9% more slowly than text in 20-line window. Comprehension of the passages did not vary as a function of window size, indicating that subjects maintained a constant level of comprehension by varying their reading rate. Implications of the results for mixing text and graphics and for limited-capacity electronic displays are discussed.

Intensity and contour effects in visual masking

Abstract In previous experiments on the detection of two sequentially presented black stimuli, it was found that the probability of detecting the first of them varied in a complex way with the temporal interval between them. A series of experiments is reported here analysing this complexity. Two types of relations are discussed: Type A curves, in which threshold duration of a target is found only to increase as the temporal separation (ISI) between the stimuli is shortened; and Type B curves, in which threshold duration of the target increase to a maximum and then decrease as the ISI is shortened. The results indicate, first, that only Type A curves occur with flashes of light as stimuli to the dark-adapted eye. Secondly, when the stimuli are small black forms presented to the lightadapted eye, Type B curves describe threshold for the first form when contrast, size and luminance of the first and second forms are similar and of moderate value; however, when differences exist between the first and second forms on these dimensions in favor of the second, Type A curves describe threshold of the first form. Other data show that a near-reciprocity exists between threshold of a target and its contrast, to describe “formation time” of the target. This reciprocity was found to hold only for flashes of light or for low-contrast grey targets. Comparison of the various results suggests that the nervous response to the interior of a form is different from that to its border, and that, consequently, the interaction of borders is different from the interaction of interiors or “bodies”. A rate-sampling mechanism is suggested as the basis of the Type A curves with both flashes of light and flashes of low-contrast grey. Some published data on metacontrast are re-analysed in these terms. A second, auxiliary mechanism seems to be involved with high-contrast black forms.

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.

Eye movement measurement of readability of CRT displays.

Eye movement was recorded as people read texts presented on a CRT in two different spacings, two different character densities, and at five different scrolling rates. Differences in efficiency of reading single- and double-spacing were statistically significant, but were of little practical significance. Character densities of 35 characters or 70 characters per line favored the smaller-size character with respect to efficiency of reading. Comparison of scrolling rates suggested that the static page was processed more efficiently than was the page scrolled at the subjects preferred rate or at a rate 10% slower than that; pages presented faster than the preferred rate were read more efficiently. Little if any change in preferred rate occurred as a function of practice with 16 pages of text. Systems in which, by program control, text was presented at rates 10% or 20% faster than the preferred scrolling rate should lead to more efficient performance, but might create some problems of user acceptance.

Specificity of operations in sentence recognition

Abstract When we read a sentence do we abstract out its semantic core and discard the surface representation, or is the surface representation an integral part of the encoded sentence? This question was studied by measurement of transfer to a second reading of a sentence of skill acquired in a first encounter with the sentence. The transfer relation was studied when the typography, language, or modality of the first and second embodiments were varied. The results favor a theory that emphasizes recognition in terms of the pattern analyzing operations that are directed at surface lexical representations. A distinction is brought out between operational or procedural memory and substantive or semantic memory. In many cases memory of procedures may be sufficient to recover the information encoded. Stage-wise processing theories do not seem to have place for such notions.

Spatial and ordinal components of form perception and literacy

Abstract We suppose that the visual nervous system possesses compensatory rectifying mechanisms by means of which it achieves “constancy” of visual recognition despite variation in physical appearance of the stimulus object. Using geometric rotations, reflections, and other transformations of text as the physical variation, we studied the recognizability of the texts and the influence that practice in reading one type of transformation exerted on the recognition of others. The mathematical structure of the training set was used as a clue to the perceptual mechanisms mediating transfer, isolating perceptual functions involving a geometric transformation and an ordinal operator. The main feature of the theory is its emphasis upon a dialogue or interaction between ongoing problem-solving processes in visual rectification and the sample being recognized. The theory developed is contrasted with other theories of pattern recognition in which concepts such as stimulus generalization, tuned detectors, and preprocessing play major roles. A relation of this theory to problems encountered among disabled readers (“dyslexics”) is also brought out.