Different pattern of hemisphere specialization between identical kinesthetic spatial and weight discrimination tasks.

Thumb position discrimination and weight discrimination tasks were examined in female students. Task procedures were identical for the position and weight tasks. Different weights were loaded for each positioning and the thumb was abducted to discriminate the weight. The Weber ratio was obtained by the method of constant stimuli and was compared between right and left. The results of position discrimination indicated left thumb (right hemisphere) superiority, while the results of weight discrimination indicated no laterality despite identical tasks. Directed attention is suggested to play an important role in the appearance of hemisphere lateralization.