Individual differences in lateralization: effects of gender and handedness.
Male and female left- and right-handers participated in 3 experiments designed to investigate 3 components of performance asymmetry in lateralized tasks. Experiment 1 used a consonant-vowel-consonant (CVC) identification task measuring quantitative differences in hemispheric abilities and hemispheric control and qualitative differences in hemispheric strategies. The quantitative data revealed that left-handers have a smaller performance asymmetry than do right-handers and that both groups have the same degree of increased accuracy when stimuli are presented bilaterally. Handedness affected the qualitative measures of men, not of women. Experiment 2 used nominal and physical letter-matching tasks with bilateral presentations and measured the flexibility of callosal function. The results suggest that left-handers have less flexible interhemispheric communication than do right-handers and show no effect of gender. Experiment 3 used a chair identification task indexing hemispheric arousal bias. Left-handers tended to have more aroused right than left hemispheres, whereas the distribution of right-handers was centered around 0 arousal bias. Intertask analyses revealed a relationship between arousal bias and metacontrol, where individuals with more aroused right hemispheres tended to use a right-hemisphere strategy in the bilateral condition of the CVC experiment. Intercorrelations between measures from the experiments revealed only a limited relationship between metacontrol patterns in the CVC task and a measure of callosal flexibility in the physical letter-matching task. The results are discussed in the context of the relationships between dimensions of hemispheric asymmetry.
Eviatar
Z
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Department of Psychology, University of Haifa, Israel.
Hellige
J B
JB
Zaidel
E
E
D000328:Adult; D001143:Arousal / Q000502:physiology; D003071:Cognition / Q000502:physiology; D003337:Corpus Callosum / Q000502:physiology; D003463:Cues; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007206:Individuality; D008297:Male; D009483:Neuropsychological Tests; D011597:Psychomotor Performance / Q000502:physiology; D012727:Sex Characteristics