Hemispheric advantages and shifts of laterality differences in visual and tactual modalities

Laterality and practice effects were examined on two visual and two tactual-kinesthetic tasks in 32 right-handed males. There was an overall RVF superiority in accuracy of discrimination of tachistoscopically presented pairs of lines and pairs of squares of dots, and a left-hand advantage in RT in judging tactually presented lines. For the visual and tactual length tasks, these advantages were present only on the first block of trials in each half of the experiment; there were no differences in the second block in each half. These shifts in laterality are discussed in terms of development of a left-hemisphere descriptive set for length.