Article

It has been hypothesized that cerebral lateralization of function enhances
cognitive performance. Evidence was found in birds and fish. However, recent
research in humans did not support this hypothesis. We aimed to replicate and
extend these findings for single- and dual-task performance in an ecologically
relevant task. We combined a word generation task which is assumed to be
primarily processed in the left hemisphere with a driving task which is assumed
to be primarily processed in the right hemisphere. For each task the individual
strength and direction of hemispheric lateralization was assessed by using
functional transcranial Doppler sonography (fTCD). For each subject (36
right-handed, 35 nonright-handed) performance was measured in the two
single-tasks and in the dual-task condition. On average, subjects showed a left
hemisphere bias for the word generation task, a right hemisphere bias for the
driving task and dual-task interference. Within subjects, lateralization of
language and driving were statistically independent. In accordance with earlier
studies, the results show no indication of a positive effect of strength of
lateralization on performance in single-tasks or dual-task efficiency. We also
found no advantage of a typical compared to an atypical or a contralateral
compared to an ipsilateral lateralization pattern. In right-handers, but not in
nonright-handers, we even found a negative relationship between strength of
lateralization and dual-task efficiency for atypically lateralized subjects. This
further supports the suggestion that lateralization does not enhance cognitive
performance in humans.
CI - Copyright (c) 2011 Elsevier Ltd. All rights reserved.

Langue : ANGLAIS