Processing electrotactile signals: relationship of speed to intelligence

Individual differences in their speed of tactile information processing were investigated in 12 male subjects by applying an electrotactile mask at various time intervals before and after the presentation of an electrotactile stimulus. An IBM PC generated both the electrocutaneous stimulus and the mask. The tactile display consisted of four concentric silver electrodes that were held against a subject´s abdominal skin surface. The stimulus signal was applied to one of these electrodes whereas the mask was applied simultaneously to all four electrodes. The pilot study found a significant correlation between a subject´s tactile information processing speed (as measured by how closely the mask could be applied in time to the stimulus without noticeable effects) and his intelligence as measured using the Raven Progressive Matrices Test