Attending to two fingers: two hands are better than one.

Abstract

The ability of subjects to attend to vibrotactile patterns presented to two fingers was explored in several experiments. The patterns were generated by two 6 column × 24 row tactile arrays. In one set of measurements, the arrays were placed in contact with the subjects’ left index and middle fingers. Both discrimination and identification tasks suggested that there was an attentional deficit in processing patterns presented simultaneously to these two fingers. A pattern presented to either the middle or index finger was identified both more accurately and more rapidly than was the same pattern divided in half and presented to two fingers. Patterns were also presented to two fingers on opposite hands, and performance measures were taken on pattern-identification tasks, on discrimination tasks, and on tasks that required subjects to combine pattern information from two fingers. All three measures showed performance to improve when the patterns were presented to two fingers on opposite hands relative to when they were presented to two fingers on the same hand. The results are interpreted to suggest, first, that subjects can process patterns simultaneously presented to two fingers on the same hand, but with some deficit due to attentional mechanisms, and second, that information from patterns presented to two fingers is processed differently depending on whether the two fingers are on the same or on different hands. There is much less of an attentional deficit in processing patterns presented simultaneously to two fingers on opposite hands.