Vibrotactile localization on the arm: effects of place, space, and age.

Although tactile acuity has been explored for touch stimuli, vibrotactile resolution on the skin has not. In the present experiments, we explored the ability to localize vibrotactile stimuli on a linear array of tactors on the forearm. We examined the influence of a number of stimulus parameters, including the frequency of the vibratory stimulus, the locations of the stimulus sites on the body relative to specific body references or landmarks, the proximity among driven loci, and the age of the observer. Stimulus frequency and age group showed much less of an effect on localization than was expected. The position of stimulus sites relative to body landmarks and the separation among sites exerted the strongest influence on localization accuracy, and these effects could be mimicked by introducing an "artificial" referent into the tactile array.