Hemispheric asymmetries in a tactile bisection task: effects of hemispace of presentation.

The validity of Bowers and Heilman's hemispace hypothesis (Neuropsychologia 18, 491-498, 1980) that "laterality effects depend upon the spatial condition in which a stimulus is presented" was examined in two tactile bisection experiments (one with adults and the other with kindergarten children). Three indices: absolute error, constant error and directional error were employed to measure the accuracy of the two hands and hemispaces. The results did not support the hemispace hypothesis, though weak spatial condition effects appeared for female subjects.