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J B Hellige

Publications and source records attributed to J B Hellige.

54 records · Page 3Linked to original sources
PubMed1984

Effects of perceptual quality on the processing of human faces presented to the left and right cerebral hemispheres.

Three experiments examined the effects of stimulus duration, retinal eccentricity, and visual noise on the processing of human faces presented to the left visual field/right hemisphere (LVF-RH) and right visual field/left hemisphere (RVF-LH). In Experiment 1 observers identified which of 10 similar male faces was presented on a screen. The single face was presented for 10, 55, or 100 ms at 1 degree, 4 degrees, or 9 degrees of visual angle to the left or right of fixation. Decreasing stimulus duration and increasing retinal eccentricity lowered face recognition. The effect of duration was the same for LVF-RH and RVF-LH trials, but the detrimental effect of increasing retinal eccentricity was larger on LVF-RH trials than on RVF-LH trials. In Experiment 2 observers indicated whether a single face from this same set was a member of a memorized set of five positive faces. The probe face on each trial was presented alone or embedded in visual noise. Visual noise increased the error rate more on LVF-RH trials than on RVF-LH trials. This effect was replicated in Experiment 3, which also required observers to make a much easier discrimination between male and female faces. In the male/female task visual noise tended to impair performance more on RVF-LH trials than on LVF-RH trials, opposite the effect for the male/male task. These results are discussed in terms of hemispheric asymmetry for global versus local features of faces, the level of feature analysis demanded by a task, and the level of feature analysis most disrupted by perceptual degradation.

Attention↗
PubMed1983

Lateralized interference of repetitive finger tapping: influence of familial handedness, cognitive load and verbal production.

The repetitive finger tapping of 24 right-handed subjects from dextral and sinistral families was evaluated. Subjects tapped with and without concurrent verbal tasks which included reciting a nursery rhyme, reading words (silent vs aloud) and solving anagrams (silent vs aloud). Overall, results indicated that the concurrent verbal tasks interfered more with right-hand tapping than with left-hand tapping. This pattern was more pronounced for familial dextral subjects than familial sinistral subjects. This latter finding was most evident with the complex verbal task of solving anagrams.

Adult↗
PubMed1983

Feature similarity and laterality effects in visual masking.

Observers attempted to recognize single letters presented to the left or right visual field when preceded or followed by a masking stimulus. When the masking stimulus contained features identical to those of the target letter, there was a left visual field (right hemisphere) advantage for target recognition. When the target and mask contained extremely different features, the opposite visual field advantage was obtained. Implications are discussed for models of hemispheric asymmetry and for interpreting visual laterality studies that use masks to reduce the overall level of performance.

Adult↗
PubMed1983

Mirror, mirror on the wall ... comments on the chimeric face task used by Roszkowski and Snelbecker (1982).

A critique is presented of the chimeric face task used as a measure of cerebral laterality by M. J. Roszkowski and G. E. Snelbecker (1982, Brain and Cognition, 1, 404-409). Problems arise because the faces used are not true mirror images of each other, but in fact differ in facial details. Data are presented to illustrate that the earlier results are not caused by cerebral laterality but by the fact that the two drawings are not equally happy--even when placed in the same left-right orientation.

Dominance, Cerebral↗
PubMed1982

Hemispheric asymmetry, early visual processes, and serial memory comparison.

Observers indicated whether a single probe letter presented to the left visual field/right hemisphere (LVF-RH) or to the right visual field/left hemisphere (RVF-LH) matched one of two, three, four, or five set letters in both name and case. For positive trials during the initial experimental session, the slope of the linear memory set size reaction time function was increased by perceptually degrading the probe letter on LVF-RH trials, but not on RVF-LH trials. In addition, perceptual degradation of the probe letter increased the intercept of the memory set size function more on RVF-LH trials than on LVF-RH trials. During subsequent experimental sessions, the same pattern of intercept results was obtained but perceptual degradation of the probe no longer changed the slope for either LVF-RH or RVF-LH trials. However, the slopes were uniformly lower on RVF-LH trials than on LVF-RH trials. The major results are consistent with hypothesized right-hemisphere efficiency for early processing stages and left-hemisphere efficiency for serial processing of alphanumeric information. The results further illustrate the importance of separating stages of processing in studies of cerebral laterality and indicate that the relative difficulty of the various stages can be a determinant of laterality results.

Cerebral Cortex↗
PubMed1981

Intercorrelation of laterality indices.

Five previously proposed laterality indices were found to correlate very highly with each other in both a verbal dichotic listening task and a work recognition task, despite large individual differences in overall accuracy. In the dichotic listening task, all of the laterality indices were positively correlated with overall accuracy; that is, accuracy increased as the magnitude of the laterality effect increased. In the word recognition task, however, no consistent relationship was found between laterality and accuracy.

Discrimination Learning↗
PubMed1980

Effects of perceptual quality and visual field of probe stimulus presentation on memory search for letters.

Observers indicated whether a single probe letter presented to the left visual field/right hemisphere (LVF-RH) or to the right visual field/left hemisphere (RVF-LH) was contained in a memory set of 2, 3, 4, or 5 letters. For positive trials, the increase in reaction time caused by perceptually degrading the probe letter became progressively larger as memory set size became larger when the probe was presented to the LVF-RH but not when the probe was presented to the RVF-LH. These results were obtained regardless of whether the case of the probe letter varied randomly (Experiment 1) or only capital letters were used (Experiment 2). The results on LVF-RH trials suggest a relatively visuospatial memory comparison process, whereas the results on RVF-LH trials suggest a more abstract memory comparison process. In addition to these effects, the intercept of the memory set size function was lower on LVF-RH trials than on RVF-LH trials when the probe letter was perceptually degraded, consistent with the hypothesis that the right hemisphere is more efficient than the left at early visuospatial processes. Perhaps it is this efficiency at early visuospatial processes that produces the bias toward visuospatial memory comparison on LVF-RH trials.

Discrimination Learning↗
PubMed1980

Developmental differences in visual backward masking.

2 experiments were conducted to examine developmental differences in visual recognition masking when verbal encoding and response demands are minimized. Precautions were taken in the experiments to ensure the implication of the central visual system in the backward-masking component of each experiment. Sampling was conducted across the kindergarten, third-grade, sixth-grade, and college levels. In the first experiment, no-mask target recognition was set at 100% correct. The results indicated systematic grade differences in backward masking such that older children and adults showed more rapid recognition improvement across stimulus onset asynchronies (SOAs) than did young subjects (i.e., a grade x SOA interaction). Although this finding could be interpreted to suggest developmental differences in the rate of visual information processing, such an interpretation would be inappropriate. The problem is that the masking functions for all grade levels reach asymptote at 100% correct (i.e., a ceiling effect). Thus, the grade X SOA interaction could have been produced for reasons other than rate-of-processing differences (e.g., developmental differences in the quality of stimulus reception). Thus, experiment 2 was designed to assess this possibility by evaluating developmental differences in visual backward masking when no-mask target recognition was set at the 75% level for the grades sampled. The grade x SOA interaction observed in experiment 1 was not observed in experiment 2. The results from the studies indicate that, when the ceiling effects in no-mask target recognition are removed, the visual information processing rates for children and adults can be considered equivalent.

Adolescent↗
PubMed1979

Figural relationship effects and mechanisms of visual masking.

In each of three visual pattern masking experiments, four curved letters (C, O, Q, S) and four angular letters (E, I, L, T) served as targets preceded or followed by either a curved mask (Q,S, and C superimposed) or an angular mask (T and E superimposed). With a dark fixation and interstimulus interval field and target-mask engergies that produce clearly identifiable targets, the following figural relationship effects were found. At stimulus onset asynchronies (SOAs) from 0 to 20 msec (in both forward and backward masking), target recognition was more accurate when targets and masks overlapped exactly (same features) than when they did not (different features). At backward masking SOAs beyond 20 msec, this pattern was reversed, but there was no such reversal in forward masking. Such results indicate that the dominant mechanism of masking at SOAs from 0 to 20 msec is luminance summation over time but that luminance summation gives way to feature-specific interference at longer SOAs. Subsequent experiments demonstrate that (a) luminance summation effects are reduced by using bright fixation and interstimulus fields and (b) feature-specific interference is eliminated by using low-energy (and, therefore, less than perfectly identifiable) targets and masks.

Adult↗
PubMed1979

Information processing in the cerebral hemispheres: selective hemispheric activation and capacity limitations.

Several previous experiments have found that concurrently maintaining verbal information in memory influences visual laterality patterns (e.g., Hellige & Cox, 1976; Kinsbourne, 1975). The present article critically reviews existing experiments and reports five additional experiments designed to identify the mechanisms responsible for such effects. Experiment 1 demonstrates that laterality patterns are not influenced by a concurrent memory task that does not require verbal processing. (The verbal nature of the concurrent task was an important aspect of previous experiments.) Experiments 2 and 3 were designed to determined whether concurrent verbal memory primarily influences very early visuospatial processes or later processes such as those involved in visuospatial memory. In Experiment 2, observers indicated whether two simulteneously presented nonsense forms had the same shape. Observers held 0, 2, 4, or 6 words in memory during each shape judgment trial. Responses were faster when the forms were presented to the left visual field--right hemisphere (LVF-RH) than to the right visual field--left hemisphere (RVF-LH). This effect did not interact with memory set size. In Experiment 3, observers indicated whether either of two simultaneously presented forms was identical to a target form held in memory. Observers held 0, 2, or 6 words in memory on each trial. On same-as-target trials, responses were faster on LVF-RH trials than on RVF-LH trials in the no-word memory condition; this difference was reversed in the two-word and six-word conditions. The combined results of Experiments 2 and 3 suggest that concurrent verbal memory influences stages of processing beyond the initial registration of visuospatial information. Experiments 4 and 5 examined the influence of concurrent verbal memory on verbal laterality tasks. Observers indicated whether two simultaneously presented letters of different cases had the same name. In Experiment 4, different groups of observers held 0, 2, 4, or 6 words in memory on each letter-pair trial. In Experiment 5, memory set size was manipulated within subjects. On the same-pair trials of Experiment 4 and the first session of Experiment 5, responses in the no-memory condition were faster on RVF-LH trials than on LVF-RH trials; this difference was reversed in all of the work memory conditions. This shift is opposite to that found when the laterality task does not require verbal processing and further indicates that concurrent verbal memory influences processing stages beyond those that are common to the form-pair and letter-pair tasks. Neither directness-of-pathway nor attention-gradient laterality models can explain the entire pattern of results from the present experiments. Rather, the results suggest that the left hemisphere functions as a typical limited-capacity information processing system that can be influenced somewhat separately from the right hemisphere system.

Cerebral Cortex↗
PubMed1978

Visual laterality patterns for pure- versus mixed-list presentation.

In Experiment 1, an overall left visual field advantage for nonverbal form recognition was found in a pure list of forms, but an overall right visual field form recognition advantage was found when the form trials were randomly intermixed with word recognition trials. Form complexity also influenced the form recognition laterality pattern, but the complexity effects were independent of (i.e., additive with) those produced by randomly mixing forms with words. Experiment 2 found that the mixed-list laterality pattern was unchanged by a pretrial cue indicating whether a word or form would follow. Experiments 3 and 4 demonstrated that holding two nouns in memory on each trial in a pure list of forms has much the same effect on laterality pattern as mixing forms with words but that the combined effect of these two variables is no larger than the effect of either variable alone. The entire pattern of results suggests that (a) laterality patterns are caused by the interaction of several factors, (b) the effects of random mixing and concurrent verbal memory are both caused by selective left-hemisphere activation, and (c) the form-complexity effects are caused by some other mechanism--perhaps subtle difference in stimulus codability.

Discrimination, Psychological↗
PubMed1976

Effects of concurrent verbal memory on recognition of stimuli from the left and right visual fields.

Two experiments examined the effect of concurrently holding 0, 2, 4, or 6 nouns in memory on the recognition of visual stimuli briefly presented to the left or right visual fields. When stimuli to be visually recognized were complex visuospatial forms it was found that a relatively easy memroy load of 2 or 4 nouns improved visual recognition accuracy on right visual field (left-hemisphere) trials relative to the no-memory condition; however, a more difficult memory load of 6 nouns decreased visual recognition accuracy to a level slightly below the no-memory condition. There were no effects of concurrent verbal memroy on visual form recognition on left visual field (right-hemisphere) trials. When the stimuli to be visually recognized were words it was found that a relatively easy memroy load of 2 or 4 nouns improved visual recognition accuracy and a more difficult load of 6 nouns decreased visual recognition accuracy on both left and right visual field trials. The complete pattern of results indicates that several factors including cerebral hemisphere specialization, stimulus codability, selective perceptual orientation, and selective cerebral hemisphere interference interact in systematic ways to produce overall visual laterality effects.

Dominance, Cerebral↗
PubMed1975

Hemispheric processing differences revealed by differential conditioning and reaction time performance.

Two different experimental procedures were used to examine (a) information-processing differences between two groups of subjects (Cs versus Vs) identified by the form of their conditioned eyeblinks; (b) information-processing differences between the right and left cerebral hemispheres; and (c) parallels between hypothesized C-V differences and right-left hemisphere differences. In the first experiment, the evocative command words BLINK and DON'T BLINK served as positive and negative conditioned stimuli. It was found that Vs gave more conditioned eyeblinks than Cs and that differential eyelid conditioning of Vs more than Cs was influenced by the semantic content of the stimuli. More importantly, the conditioning performance of Cs was more influenced by the semantic attributes of the stimuli when they were presented directly to the right visual field (left hemisphere) than when they were presented directly to the left visual field (right hemisphere). In contrast, the conditioning performance of Vs was equally influenced by the semantic attributes regardless of which hemisphere received direct stimulation. A second experiment was designed to determine whether such hemisphere-of-presentation differences for Cs versus Vs could also be obtained in a very different task. Subjects classified as Cs or Vs during a differential eyelid conditioning task then performed two same-different reaction time (RT) tasks that required discrimination of complex polygons in one case and the names of letters in another. On each RT trial both stimuli of a pair appeared briefly either in the center, left, or right visual field. For both Cs and Vs RTs to complex polygon pairs averaged 20 msec faster on left visual field trials than on right visual field trials, consistent with current hypotheses about right-hemisphere specialization for visuospatial processing. In contrast, the results for letter pairs generally confirmed the C-V differences found in Experiment 1. That is, the right visual field (left-hemisphere) advantage for these verbal stimuli was once again larger for Cs than for Vs. The present results suggest that the two groups of subjects (Cs versus Vs) differ qualitatively in the modes of information processing that they typically employ. The results also suggest that these different modes of processing are related to aspects of cerebral hemisphere organization and that even right-handed individuals may differ from each other in the extent to which each cerebral hemisphere is mobilized for a given experimental task. Such individual differences must be incorporated into both models of classical eyelid conditioning and models of cerebral hemisphere specialization.

Conditioning, Classical↗