Detection, Discrimination & Localization: The Psychophysics of Touch

Detecting and discriminating touches on your fingertip and other highly sensitive body parts has been a paradigm in somatosensory science since the birth of psychophysics in the nineteenth century. By isolating a body part and applying discrete stimuli over many repetitions, the limits of somatosensation and bodily perception can be discovered. This chapter will focus on two methods of studying discriminative touch in the temporal and spatial domains: vibrotactile perception and spatial acuity. Different psychophysical approaches and experimental designs will be described and evaluated in terms of their validity, efficiency, and reliability. Practical and participant-specific difficulties will be noted. Vibrotactile and spatial acuity methods offer relatively cheap and reliable measures of somatosensation, often suitable for undergraduate student projects. Yet care and experimentation is required to ensure that the experimental design is adequate, and the data collection is sufficient to answer your theoretical question.