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D B Boles

Publications and source records attributed to D B Boles.

12 recordsLinked to original sources
PubMed1992

Factor analysis and the cerebral hemispheres: temporal, occipital and frontal functions.

Three experiments are reported that use a number of lateralized tasks believed to draw on processes localized to the temporal, occipital or frontal lobes. Oblique factor analyses of the resultant asymmetries indicate the existence of nine lateralized functions, characterized as auditory lexical, facial figural, facial motive, spatial attentive, spatial positional, spatial quantitative, tactile figural, visual lexical, and visual phonetic in nature. Most functions are uncorrelated, but as in an earlier report (Boles, Neuropsychologia 29, 59-91, 1991), both positive and negative correlations are observed. These outcomes continue to be consistent with neurodevelopmental theory, and inconsistent with lateralization strength, hemisphericity, and independence views of individual differences in lateralization.

Arousal↗
PubMed1992

Fast visual generation: its nature and chronometrics.

The fast-generation model for the matching of mixed-case letter pairs (e.g., Aa, Ab) states that one or both members of a pair activate visual representations in memory of the opposite case, supporting "same" or "different" responses through crossmatching to representations of the pair members themselves. Here the reaction time and error results of three experiments using simultaneous matches support a specific variant of the model in which generation proceeds from the uppercase letter. Furthermore, a manipulation of stimulus onset asynchrony in a fourth experiment using near-simultaneous matches indicates that fast generation produces a visual representation that occurs within 67 msec of initiation and that decays within 200 msec. A fifth experiment contrasts simultaneous and successive matches and in the case of successive matches finds evidence in support of a regeneration process acting after an initial decay. Models of mixed-case matching that are based on the phonetic representation of letter names, or on abstract-letter identities, completely fail to account for the results. Fast generation is distinguishable from slow generation in that it shows fast (vs. slow) dynamics, rapid decay (vs. maintainability), no imagery (vs. imagery), and (probably) automatic (vs. controlled) processing.

Attention↗
PubMed1991

Factor analysis and the cerebral hemispheres: pilot study and parietal functions.

Although research on lateral differences has proliferated, attempts to specify fundamental dichotomies of hemispheric processing have yielded less than satisfactory results. The factor analysis of behavioral asymmetries can provide a different approach by helping to identify common functions underlying disparate tasks. It can also provide information on individual differences and interrelationships among functions. Here, the viability of the approach is demonstrated with a small pilot study (N = 29), and with two larger experiments (N = 70 and N = 60) that stress parietal lobe function. Seven lateralized functions were identified: auditory lexical, spatial attentive, spatial positional, spatial quantitative, tactile figural, visual emotional and visual lexical. A range of positive, negative and null correlations was found between functions, contrary to lateralization strength, hemisphericity, and independence models of individual differences in lateralization. However, a pattern of intercorrelations was observed among functions believed to be localized to the perisylvian region (Brodmann areas 22 and 39), which is consistent with the neurodevelopment theory of Geschwind and Galaburda (Cerebral Lateralization Biological Mechanisms, Associations and Pathology, The MIT Press, Cambridge, MA, 1987).

Adult↗
PubMed1990

What bilateral displays do.

Bilateral presentations of stimuli produce asymmetries larger than those of unilateral presentations, an effect that exists across modalities. In the case of visual field differences at least 13 hypotheses of the effect have been proposed, 6 of which suggest that some form of hemispheric interaction is responsible for the bilateral advantage. Previous research has eliminated all 7 noninteraction hypotheses, has supported the class of hemispheric interaction mechanisms, and has ruled out two specific instances of the latter. Here four experiments test the remaining hypotheses. The results support the homolog activation hypothesis, which states that bilateral stimulation by similar stimuli activates homologous areas of the two hemispheres, disrupting communication between the areas. The other hypotheses were eliminated.

Arousal↗
PubMed1989

Do visual field asymmetries intercorrelate?

Lateralized word and bargraph recognition tasks were presented to 22 right-handed and 15 left-handed subjects. The correlation between the opposite reaction time asymmetries for the tasks was significant, and indicated that individual subjects generally showed strong lateralization for one task and weak lateralization for the other. The results are viewed as inconsistent with models of individual differences in hemispheric function that stress strong hemisphericity, lateralization strength, or independent functions. However, they are consistent with a model stressing weak hemisphericity. Also potentially consistent with the results is the neurodevelopmental theory of Geschwind and Galaburda (Cerebral Lateralization: Biological Mechanisms, Associations and Pathology, MIT Press, Cambridge, Massachusetts, 1987), if it is assumed that the lateralized functions reflected by the tasks are subserved by homologous anatomical areas. Compared to right-handers, left-handers tended to produce a smaller correlation between the tasks, as well as weaker hand preferences, and smaller and less reliable field asymmetries.

Adult↗
PubMed1989

Word attributes and lateralization revisited: implications for dual coding and discrete versus continuous processing.

Three attributes of words are their imageability, concreteness, and familiarity. From a literature review and several experiments, I previously concluded (Boles, 1983a) that only familiarity affects the overall near-threshold recognition of words, and that none of the attributes affects right-visual-field superiority for word recognition. Here these conclusions are modified by two experiments demonstrating a critical mediating influence of intentional versus incidental memory instructions. In Experiment 1, subjects were instructed to remember the words they were shown, for subsequent recall. The results showed effects of both imageability and familiarity on overall recognition, as well as an effect of imageability on lateralization. In Experiment 2, word-memory instructions were deleted and the results essentially reinstated the findings of Boles (1983a). It is concluded that right-hemisphere imagery processes can participate in word recognition under intentional memory instructions. Within the dual coding theory (Paivio, 1971), the results argue that both discrete and continuous processing modes are available, that the modes can be used strategically, and that continuous processing can occur prior to response stages.

Adult↗
PubMed1987

Reaction time asymmetry through bilateral versus unilateral stimulus presentation.

Previous research indicates that bilateral stimulation of the visual fields results in larger asymmetry than unilateral stimulation. However, the research has largely been limited to percentage correct studies. Here, three experiments employ reaction time (RT) measures, and show that the bilateral advantage generalizes to RT, and across spatial and verbal stimulus materials (bargraphs, letters, and words). Visual field differences average about six times larger with bilateral than with unilateral presentation. Beyond promising increased power to detect hemispheric differences, the results argue against structural and attentional models of behavioral asymmetry and support a dynamic (hemispheric interaction) model.

Attention↗
PubMed1986

Hemispheric differences in the judgment of number.

Two manual reaction-time experiments examined visual field differences for the judgment of number. All told, three tasks (recognition/enumeration, magnitude judgment and oddity judgment) were performed on three nonverbal indicators of number (dot clusters, bargraphs and dials) and two verbal indicators (word names of numbers and digits). The results indicated that field differences depended largely on display format, not on the task. Thus, dot clusters, bargraphs and dials all showed a left visual field superiority, while words showed a right visual field superiority. There was no evidence of lateralization for digits.

Functional Laterality↗
PubMed1985

The effects of display and report order asymmetries on lateralized word recognition.

Word recognition typically is better or faster in the right visual field than in the left visual field, an effect that often interacts with the handedness of subjects or the phonetic characteristics of the language employed. While these findings suggest a hemispheric locus, it is possible that the field difference is confounded with display or report order asymmetries. Here two experiments manipulate word orientation (horizontal vs. vertical), letter symmetry, and report order variables, and they demonstrate a generalized right field superiority that fails to interact with other factors. Since the superiority appears even when all apparent artifactual asymmetries are eliminated, the findings support a hemispheric interpretation.

Dominance, Cerebral↗
PubMed1983

Visual and phonetic codes and the process of generation in letter matching.

Physically identical letter pairs are matched more quickly than are nominally identical or nonidentical pairs, which is an effect usually interpreted as resulting from the use of a visual memory code versus a phonetic or name code. However, prior manipulations of phonetic confusion and visual-field lateralization have provided little evidence consistent with this notion. Here, three reaction time experiments suggest through converging confusion and visual-field manipulations that a phonetic code is not used in either simultaneous or successive letter matching. Two additional experiments yield confusion evidence consistent with a rapid visual generation process underlying nominally identical and nonidentical matches, emphasizing the role of visual memory processes in all of the commonly used same-different letter-matching tasks. Implications for coding and hemispheric theories are discussed.

Form Perception↗