A new millennium in cognitive neuropsychology research: the era of individual differences?
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Biomedical subjects
Publications and source records attributed to M W O'Boyle.
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Alpha power (8-12 Hz) was monitored over the frontal, temporal, parietal and occipital lobes of the left and right cerebral hemispheres while participants mentally rotated three-dimensional shapes to match a specified target. By comparing the activational patterns generated during three experimental conditions, each designed to systematically isolate the involvement of the various subcomponents comprising this mental rotation task, it was suggested that the right frontal lobe mediates encoding and comparison/decision processes, while the left parietal and the left temporal region appear most involved in the generation of images and their mental rotation. A preliminary model describing the cooperative interaction of these cortical regions during mental rotation tasks is proposed.
Alpha wave (8-12 Hz) activity was monitored over the four lobes of the left and right cerebral hemispheres while 12 male and 12 female participants mentally manipulated circles and arcs to determine size matches. Four task conditions were tested, each designed to tap into the visual encoding, image generation, mental rotation, and comparison/decision subcomponents comprising this task. Males were more accurate than females in making such matches, and in all conditions they exhibited a significant alpha power reduction asymmetry, with the right frontal lobe being more active than the left frontal lobe. Females showed a pattern of activation that was bilaterally distributed, primarily to the frontal and temporal regions. These findings suggest a difference in the functional organisation of the male and female brain which may contribute to the reported sex difference in the performance of some spatial tasks.
This paper reports the factor structure of a 37-item personality questionnaire intended to be predictive of driving performance in elderly persons. Subjects were 191 persons 63 years of age of older, about half of whom also were given perceptual/cognitive tasks and drove on a closed driving course. Although the personality questionnaire did not predict driving skill, the factor structure of the questionnaire is of interest. Of several factor analyses, the most satisfactory was a 2-factor solution. We interpreted the approximately orthogonal factors as measuring what we labeled Competence and Emotionality.
O'Boyle and Benbow (1990) have suggested that enhanced involvement of the right hemisphere (RH) during basic information processing is a neuropsychologic characteristic of the gifted brain. To provide converging evidence for this hypothesis, the present study was conducted using a concurrent finger-tapping paradigm. Specifically, 24 mathematically precocious and 16 average ability adolescent males were required to tap a key as quickly as possible while sitting silently (baseline condition), concurrently reading a paragraph aloud (verbal load), or encoding a random form into memory (spatial load). For average ability subjects, the concurrent verbal load reduced tapping rate for the right but not the left hand, reflecting a division of LH resources between linguistic processing of the paragraph and motor control of the contralateral hand. In contrast, for gifted subjects, both their left- and right-hand tapping rates were significantly reduced, suggesting that both hemispheres were engaged during verbal processing. The concurrent spatial task produced a small but reliable reduction in finger-tapping rate for both the left and right hand in each group. These findings provide additional support for the notion that enhanced reliance on RH functioning is a physiological correlate of mathematical precocity in gifted males.
Two experiments tested perceptual processing of Garner and Clement's (1963) good and poor five-dot patterns by the left and right hemispheres. Two (good) patterns were from four-member equivalence sets, and the other (poor) pattern was from an eight-member equivalence set. One of the good patterns formed a T shape that could be processed as a linguistic unit. In Experiment 1, 80 right-handed subjects made same-different judgments for lateralized 200-msec paired presentations of these patterns. When both presentations were to the RVF/LH, response latency was faster for the T pattern than for the other two. When both presentations were to the LVF/RH, response latency was faster for the two good patterns than for the poor pattern. When the first pattern was presented to the RVF/LH and the second was presented to the LVF/RH, response latencies were lower for the two good patterns than for the poor pattern. Also, when the first pattern was presented to the LVF/RH and the second was presented to the RVF/LH, response latency was faster for the T pattern than for the other good pattern which was, in turn, faster than for the poor pattern. Experiment 2 used a duration judgment task (Avant & Lyman, 1975) to test effects of pattern goodness on apparent durations of pre- and postmasked 10-msec pattern presentations. With left hemisphere inputs, presentations of good patterns were judged to be longer than presentations of the poor pattern. When each hemisphere compared the T and the other good pattern, presentations of the T pattern were judged to be longer, and the right hemisphere further discriminated among pattern orientations. Presentations of the T pattern to each hemisphere were judged to be longer than presentations of the poor pattern, and both hemispheres discriminated among orientations of both patterns. These results indicate that the two hemispheres can, during perceptual processing, function cooperatively, and that both prerecognition and conscious perceptual operations are guided by task demands.
Two experiments have been conducted to examine preference patterns of inexperienced users for symbols intended to communicate photocopier functions and the relative effectiveness with which keywords, subject-generated symbols and industry symbols are matched to verbal descriptions of various photocopier operations. First, inexperienced photocopier users were asked to draw a set of symbols that they believed best represented 16 designated copier functions, and subsequently a second set of subjects compared these generated symbols with those currently used by the photocopier industry, and gave their preference. Inexperienced users generally preferred the subject-generated symbols, except for those involving the fairly complex 'sidedness' functions. Secondly, inexperienced users were asked to match keywords, generated symbols and industry symbols to verbal descriptions of the same 16 photocopier functions. Essentially, keywords and generated symbols did not differ in matching accuracy, while both were more accurately matched than industry symbols. However, the complexity of the photocopier function to be conveyed and the familiarity of the user with a given copier operation did produce several exceptions to this overall pattern. The results suggest that careful ergonomics research can produce symbols that are at least as effective as keywords in conveying photocopier functions. The universal nature of such symbols and their possibilities for cross-cultural use are also noted.
A preliminary electroencephalographic (EEG) investigation was conducted to determine if the pattern of hemispheric activation in mathematically precocious youth differs from that of average math ability subjects. Alpha activity at four brain sites (frontal, temporal, parietal, and occipital lobes) over the left and right cerebral hemispheres (LH/RH) was monitored while 12- to 14-year-old, right-handed males: (a) looked at a blank slide (baseline condition), (b) judged which of two chimeric faces was "happier," and (c) determined if a word was a noun or a verb. At baseline, the LH of the precocious group was found to be more active at all four brain sites relative to that of the average ability group. During chimeric face processing, the gifted subjects exhibited a significant reduction in alpha power over the RH, primarily at the temporal lobe, while no such alpha suppression was observed in the average ability subjects. For noun/verb determinations, no significant alpha power reductions were obtained for either group. These electrophysiological data generally corroborate the behavioral findings of O'Boyle and Benbow (1990a) and support their contention that enhanced RH involvement during cognitive processing may be a correlate of mathematical precocity. Moreover, the pattern of activation observed across tasks suggests that the ability to effectively coordinate LH and RH processing resources at an early age may be linked to intellectual giftedness.
In the present study, intellectually precocious and average ability youths performed a dichotic listening task (Experiment 1) and a free-vision chimeric face task (Experiment 2). Patterns of hemispheric lateralization and the relative involvement of the left and right hemispheres during cognitive processing were assessed. In Experiment 1, the average ability youths demonstrated a right ear/left hemisphere (re/LH) superiority for identification of CV syllables, while the gifted subjects failed to show any ear/hemisphere advantage. In Experiment 2, members of both groups tended to judge the leftside smile/rightside neutral half-faces as "happier", a pattern indicative of enhanced right hemisphere (RH) arousal. Notably, the degree of RH involvement was significantly greater in the gifted as compared to average ability youths. Moreover, laterality scores of the precocious on the chimeric face task correlated with their performance on the College Board Scholastic Aptitude test (SAT), i.e. the greater the leftward bias, the higher the SAT score. These findings, taken in composite, suggest that a high level of RH involvement during cognitive processing may be related to intellectual precocity.
Previous work by O'Boyle and Sanford (1988) has demonstrated that the right hemisphere (RH) is superior to the left hemisphere (LH) in the matching of tape-recorded melodies to rhythm sequences tapped in the palms of the hands. This asymmetrical advantage was attributed to a RH superiority in the perceptual processing of intonation as compared to the rhythm component of these musical stimuli. In the present study, subjects were taught that the monotone sound of two wooden drumsticks struck together in a specified rhythm actually represented non-melodic translations of songs with identifiable melodies. After such mental associations had been formed, these non-melodic stimuli (which produced no asymmetric performance in Exp. 2 of the O'Boyle and Sanford study), now produced a RH advantage that was comparable to that induced by the original melodies. This finding suggests that the physical presence of intonation and its subsequent perceptual analysis, are not necessarily critical to the RH advantage reported by O'Boyle and Sanford (1988). Rather, the asymmetry may be related to a superior ability of the RH to generate and/or manipulate echoic images in memory.
Forty right-handed males were asked to identify four-letter names traced in either the right or left palms while their eyes were closed. The name stimuli were traced in a right-side-up or upside-down orientation (i.e., vertical or rotated 180 degrees). Mean percentage of errors served as the dependent variable. On the first block of 40 trials, the left palm/right hemisphere (LP/RH) was significantly more accurate than the right palm/left hemisphere (RP/LH) at identifying these names. This advantage, however, was only manifest when the name stimuli were traced in the upside-down orientation. On the second block of 40 trials, as the name stimuli became more familiar and the subjects became more practiced, a similar LP/RH advantage was observed; however, the impact of the rotation variable was no longer in evidence (i.e., the LP/RH was slightly more accurate on both upright and inverted names). These results are interpreted in light of a process-oriented tactile asymmetry as proposed by M. W. O'Boyle, F. Van Wyhe-Lawler, and D. A. Miller (1987, Brain and Cognition, 6, 474-494).
Two experiments were conducted to investigate the ability of the cerebral hemispheres to match rhythm sequences tapped in the palms of the hands to tape-recorded melodies. Reaction time (RT) for same/different judgments and accuracy of responses served as the (LP/RH) advantage was found in the ability to match tapped rhythms to tape-recorded melodies, but only on Different trials. On Same trials (which were found to be somewhat easier), both hemispheres were equally efficient at making such comparisons. In Experiment 2, there was no reliable difference between the LP/RH and the RP/LH in the ability to match tapped rhythms to tape-recorded rhythm sequences which were devoid of melodic intonation (i.e., the sound of two blocks of wood struck together in a specified rhythm). The results of these experiments taken in composite lend support to the contention that the right hemisphere advantage typically reported for the processing of musical stimuli is primarily related to pitch and/or intonation rather than rhythm.
Twelve English- and 12 Urdu-speaking males, ranging in age from 18 to 30 years, were asked to assign pure-tone frequencies as a "best fit" to visually presented shapes. Six basic figures were employed (circle, ellipse, right triangle, isosceles triangle, along with two historical psycholinguistic forms--uloomu and takete) and varied on three dimensions of size, complexity, and density. The results of the study indicate that there was consistency in the assignment of pure-tone frequencies to the dimensions of the figures and that the pattern of assignment was generally similar for both English- and Urdu-speaking subjects alike. Specifically, for both language groups, round figures (circles and ellipses) were assigned significantly lower frequencies than other stimuli. Also, complex and dense figures (i.e., those designed to simulate "visual depth" and "visual texture," respectively) received significantly higher frequency settings than those stimuli not possessing these dimensions. Additional analyses revealed several factors that may have contributed to the observed pattern. For example, Urdu subjects of the English proficiency produced frequency assignments that closely resembled those of the English-speaking subjects, while subjects of low English proficiency produced a pattern that was somewhat different, particularly with regard to round, complex figures. Length of residency in the United States (6 months, 1 year, or 2 years), however, did not significantly influence frequency assignments for the Urdu subjects. These results are discussed in terms of "cross-cultural" versus "language-specific" phonetic symbolism.
Three experiments were conducted to examine the relative ability of the cerebral hemispheres to identify capital letters traced in the palms of the hands. In Experiment 1, letters were presented either right side up or upside down, and the subject's task was to name the letter aloud or point to an identical letter using the stimulated hand. Analysis of the accuracy data revealed that the left palm/right hemisphere (LP/RH) performed this task significantly better than did the right palm/left hemisphere (RP/LH), particularly when the stimuli were presented in the upside-down orientation. In Experiments 2 and 3, subjects performed the same letter identification task; however, on half the trials, they were required to maintain either a spatial or verbal concurrent memory load (i.e., a 24-point Vanderplas & Garvin form or six low-imagery nouns, respectively). In the no-load condition of Experiment 2 (spatial forms), the previously observed LP/RH advantage was replicated. However, in the load condition, this LP/RH superiority was no longer in evidence. In Experiment 3 (low-imagery nouns), the presence of a concurrent verbal task had minimal impact on the previously observed performance asymmetry as the LP/RH advantage was obtained in both the no-load and load conditions. The results of the three studies taken in composite suggest that (1) the operations utilized to identify letters traced in the palms of the hands are primarily spatial in nature and (2) that the observed performance asymmetry may be attributed to a right hemisphere superiority for the analysis and codification of information along a spatial dimension. These findings are discussed in terms of a "process-oriented" model of hemispheric asymmetry.
Two memory search experiments were conducted using vertically oriented four-letter names and human faces as stimuli. Subjects were required to indicate as quickly and as accurately as possible whether or not a single probe stimulus (presented for 150 msec to either the left or right visual field) was contained in a set of 2, 3, 4, or 5 items being held in short-term memory. The probe stimuli were presented alone (clear condition) or centrally embedded in a matrix of dots (degraded condition). In Experiment 1 (involving names), a right visual field/left hemisphere advantage was obtained and pinpointed at the encoding stage rather than at the memory comparison stage of the information-processing system. For Experiment 2 (involving human faces), no hemispheric advantage was readily observed. In each experiment, both the left hemisphere and the right hemisphere employed an abstract memory comparison operation from which the effects of probe degradation have been removed. These results are discussed in terms of their implications for various models of hemispheric asymmetry.
Conflicting predictions of reinforcement and neophobia-arousal theories were evaluated in a simple choice task. Four groups of C57BL/6J mice were administered daily two-trial tests in a uniform T-maze for 10 consecutive days. For three groups, the contingencies of footshock treatments were manipulated to reinforce alternation, perseveration, or both. A control group that was not administered footshock alternated, but all three groups that were stressed perseverated more and more across tests, despite the differences in reinforcement contingencies. These results are inconsistent with the predictions of reinforcement theory but consistent with the view that stressed or aroused animals are neophobic and use nonassociative learning (habituation) to distinguish between novel and familiar alternatives.
Both frequency and speed of utterance have been implicated in studies of phonetic symbolism. Therefore, these two variables were manipulated independently. Three monosyllables were recorded and distorted by either increasing or decreasing frequency, holding speed constant, and by increasing or decreasing speed, holding frequency constant. The subjects were 15 college students who rated the resulting 15 stimuli (3 monosyllables X fast speed-normal frequency, slow speed-normal frequency, normal speed-high frequency, normal speed-low frequency, and normal speed-normal frequency) using 15 bipolar adjective scales, chosen on the basis of previous semantic differential and phonetic symbolism research. Five separate factor analyses were applied to the data. It was found that the normal speed-low frequency, slow speed-normal frequency, and normal speed-normal frequency stimuli generated approximately the same factors, while the fast speed-normal frequency and normal speed-high frequency stimuli generated factors similar to each other but with some notable differences. Separate analyses of variance were applied to the bipolar adjectives using speed, frequency, and vowels as main effects. The 15 analyses showed that subjects did judge the monosyllables as different on the basis of both speed and frequency. The implications of this study for phonetic symbolism research are discussed.
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.