Reaction time measurement of temporal integration and organization of form

Temporal integration of patterned stimuli was investigated by introducing an interstimulus interval (ISI) between brief exposures of two matrices of illuminated squares. These matrices were identical except for their spatial displacement, arranged such that they could be superimposed to yield either horizontal or vertical stripes. Choice reaction times to the composite stripe orientation were a progressively increasing function of ISI, suggesting some integration over an ISI range in excess of 224 msec. Similar functions were obtained with both regular and irregular order of ISI presentation. The results from an additional experiment employing an extraneous warning signal discounted the possibility that preparatory factors developing over the ISI were responsible for the obtained reaction time functions.     

Selective attention and serial processing in briefly presented visual displays

Displays of eight capital letters were presented in a circular arrangement around a central fixation point at tachistoscopic durations. Under different experimental conditions, one or two indicators, presented either 250 msec before, simultaneously with, or after the display, designated the letters that S was to report. The arrangement of conditions permitted inferences as to the order in     

Visual search under conditions of very rapid sequential Input rates

The purposes of the present experiment were to provide information on rate of information processing in visual perception and to determine the degree to which the “sequential blanking” effect found by Mayzner. Tresselt, and Cohen (1966) constituted a limitation on rapid sequential input rates. A 10-channel tachisto scope was employed that permitted controlled durations of each of the 10 channels and the 9 inter channel intervals. The S’s task was one of visual search or detection in which he searched for a target letter among noise letters. A temporal interval forced-choice procedure was used. In addition to varying the rate at which letters were sequentially presented, various irregular temporal spatial orders of presentation of the letter sequences were employed and the direction and orientation of the display in the visual field was varied as was also the spacing between adjacent stimuli. No evidence of “sequential blanking” was found either in terms of the detection criterion or in the Ss’ phenomenal reports. Detection performance was as good at a rate of 2 1/2 msec per letter as it was at a rate of 30 msec per letter.     

Visual backward masking as measured by voice reaction time

Instead of using percent correct identifications or detections as the dependent variable, latency in voicing the target stimulus was measured in a backward masking paradigm. Reaction time (RT) to target letters was reliably increased when they were simultaneously encircled by a black ring mask of a size found to produce masking using an identification or detection criterion. The masking function in terms of RT was typical in shape, a decreasing function of stimulus onset asynchrony (SOA) over an interval of 150 msec. Since the target remained “on” when the mask appeared, the results are incompatible with an erasure interpretation of masking effects. Analyses of the variances of the RTs supported an interpretation of a progressive decrease in masking effects as SOA increased.     

Binocular summation in the perception of form at brief durations

Visual form identification at brief durations was studied under: (a) monocular presentation; (b) dichopic presentation where the same form was presented successively on noncorresponding areas; and (c) dichopic presentation where the same form was presented on corresponding areas simultaneously and successively. Form identification for noncorresponding area dichopic presentation was at the level to be expected from 2independent chances to perceive. Both simultaneous and successive dichopic presentation on corresponding areas gave identification accuracy significantly above the level predicted by the assumption of independence. However, the binocular summation was not complete. When the same amount of energy entering the visual system in a binocular presentation was given in a monocular stimulation, the latter condition gave significantly better identification.     

The Influence of Child-Directed Speech on Word Learning and Comprehension

This paper describes an investigation into the function of child-directed speech (CDS) across development. In the first experiment, 10–21-month-olds were presented with familiar words in CDS and trained on novel words in CDS or adult-directed speech (ADS). All children preferred the matching display for familiar words. However, only older toddlers in the CDS condition preferred the matching display for novel words. In Experiment 2, children 3–6 years of age were presented with a sentence comprehension task in CDS or ADS. Older children performed better overall than younger children with 5- and 6-year-olds performing above chance regardless of speech condition, while 3- and 4-year-olds only performed above chance when the sentences were presented in CDS. These findings provide support for the theory that CDS is most effective at the beginning of acquisition for particular constructions (e.g. vocabulary acquisition, syntactic comprehension) rather than at a particular age or for a particular task.     

The DSM‐IV‐TR and Culture: Considerations for Counselors

Although counselors receive training in both diagnosis and cultural foundations of human behavior, little literature or research integrates these 2 areas in order to facilitate culturally sensitive diagnostic practices. The authors attempt to rectify that lack by providing a review of the literature on the controversies associated with traditional diagnosis of cultural groups that differ from the dominant culture. Practical guidelines for culturally sensitive diagnosis are provided.     

Form of redundancy as a determinant of tachistoscopic word recognition

Single letters and redundant CVCs and CCCs were presented at threshold durations and followed by a pattern mask. Performance on three-letter stimuli was greater than on single letters. The increased performance was consistent with a state model of perceptual independence. Conditional redundancy increased the frequency with which all three letters were accurately reported as compared to correlational redundancy. Meaning and pronounceability had little effect on performance.