Murray J. White

Naming and categorization of tilted alphanumeric characters do not require mental rotation

Single letters and numbers were shown at different angular orientations in the frontal plane, in both forward and backward (mirror-image) versions. In three separate conditions, subjects were required to discriminate the stimuli on the basis of version, category (letter, number, and name (G, 2, etc.). There was a pronounced effect of orientation on version judgments but none at all on category and name judgments, indicating that the identification of a tilted character requires neither the assignment of a cognitive up-down axis nor mental rotation to the upright. Nevertheless, reaction times for backward versions were slower than reaction times for forward versions in both category and name conditions, implicating some sort of interhemispheric transfer process. No support was obtained for the so-called “conceptual category” effect in that reaction times for category judgments were consistently slower than reaction times for name judgments.

Parallel-serial processing and hemispheric function

Abstract In one experiment 14 subjects made same-different responses to geometric forms varying in number from two to four, and presented randomly in the left or right visual hemifields. In a second experiment two different groups of subjects ( N 1 = N 2 = 6) responded to letters, varying in number from two to four which could be matched on either nominal or physical identity. In both experiments reaction times were faster for stimuli directed to the right hemisphere and in no condition did reaction times increase with increasing number of stimuli. Implications for a relationship between mode of processing and hemispheric function were discussed.

DOES CEREBRAL DOMINANCE OFFER A SUFFICIENT EXPLANATION FOR LATERALITY DIFFERENCES IN TACHISTOSCOPIC RECOGNITION

Two major classes of hypothesis have been advanced to account for visual laterality differences. One stresses the importance of factors in determining an attentional scanning of the stimulus traces; a second emphasizes functional differences between the cerebral hemispheres. In a recent series of experiments McKeever and Huling have concluded that cerebral dominance factors offer a sufficient explanation for visual laterality differences. A review of McKeever and Hulings findings and of other relevant experiments shows that something more than cerebral dominance is required to account for tachistoscopic laterality effects.

Effect of Photographic Negation on Matching the Expressions and Identities of Faces

In four experiments, participants made speeded same – different responses to pairs of face photographs showing the same woman or different women with the same expression or different expressions. Compared with responses to positive pairs, negative pairs were matched more slowly on identity than on expression. A secondary finding showed that face expressions (same, different) influenced identity responses, and identities influenced expression responses, equally for positive and negative pairs. The independence of this irrelevant-dimension effect from the contrast effect supports the conclusion required by the main finding—that negation slows perceptual encoding of surface-based information used for identification more than it does encoding of edge-based information used for expression recognition.

Identification and categorization in visual search

Seven experiments were addressed to the general question of whether the identification of letters and numbers is a more rapid process than the categorization of such stimuli. Subjects were required to make a single response if a target stimulus specified by name (e.g., “A,” “2”) or designated by category class alone (e.g., “letter,” “number”) was presented in a trial. The principal findings were: (1) identification reaction times (RTs) were faster than categorization RTs: (2) RTs for targets shown without a context were faster than RTs for targets shown in the context of other stimuli; (3) identification RTs for targets shown in the context of stimuli from a different conceptual-taxonomic category were faster than RTs for targets shown in the context of stimuli from the same category only when target-context stimulus discriminability differencet were optimized. The results were interpreted in terms of a two-stage processing model in which context face,ors affect the duration of an initial encoding-scanning stage and search instruction (effective memory size) factors affect the duration of the memory comparison stage.

Identification and localization within digit and letter spans

Subjects were required to identify and localize digits or letters from displays containing eight elements across the visual field, four elements in the left visual field, or four elements in the right visual field. Exposure duration, presentation condition, and type of material were found to affect recall. In addition, an interaction between element position and exposure duration was found for localization scores.

Feature-specific border effects in the discrimination of letter-like forms.

Letter-like targets (a circle and a square) were presented in one of two fixed and cued visual field locations and were shown alone, flanked by a noise stimulus on the peripheral side (side of target farthest from fixation), on the central side, or on both sides simultaneously. The adjacent target and noise stimulus borders had similar featural properties (both curved or both straight lines) or dissimilar properties (one being a curved line and one a straight line). Each of 10 subjects made a go, no-go response only when his or her designated target appeared in a display. The results showed: (1) single targets were discriminated more accurately and more rapidly than were targets shown simultaneously with noise stimuli, (2) targets having dissimilar border relationships with noise items were discriminated more accurately than were targets having similar border relationships, (3) targets in central-noise displays were discriminated more accurately and rapidly than were targets in peripheral-noise displays, and (4) there was no interaction between border relationships and noise position. The principal result relating to target-noise border featural relationship was consistent with predictions derived from models which place the locus of noise effects at the stage of stimulus feature extraction. Aspects of the results were, however, seen to be consistent with both feature extraction and response competition conceptualizations.

Prominent publications in cognitive psychology

This article identifies the 50 publications in cognitive psychology that were most frequently cited in the professional literature between 1979 and early 1982. The characteristics of these publications are discussed, and comparisons are made with other relevant findings.

On the Relation Between Productivity and Impact

The number of publications per person per year and the number of citations to published work per person per year were counted for a sample of 299 Australasian academic psychologists for the period 1970–1975. Ten per cent of the sample accounted for 36% of the publications and 10% of the sample for 60% of the citations. At the level of universities there was a relationship (r = .70) between productivity (publications) and impact (citations). Across the 242 individuals with at least one publication, there was no productivity-impact relationship (r = .10).

Retinal locus and the letter-span error function

The effect of retinal locus on the letter-span error function was investigated by requiring Ss to fixate at the left, middle, or right of lines of letters presented for 100 msec. Stimulus presentations consisted of lines of eight letters presented across the visual field, and lines of four letters presented alternately in the left and right visual hemifields. Locus of fixation and relative letter position were found to be significantly related to whether or not a letter was correctly localized. A significant interaction between locus of fixation and letter position was observed.