Optimum Information Transfer Rates for Communication through Haptic and Other Sensory Modalities

This paper is concerned with investigating the factors that contribute to optimizing information transfer (IT) rate in humans. With an increasing interest in designing complex haptic signals for a wide variety of applications, there is a need for a better understanding of how information can be displayed in an optimal way. Based on the results of several early studies from the 1950s, a general "rule of thumb" has arisen in the literature which suggests that IT rate is dependent primarily on the stimulus delivery rate and is optimized for presentation rates of 2-3 items/s. Thus, the key to maximizing IT rate is to maximize the information in the stimulus set. Recent data obtained with multidimensional tactual signals, however, appear to contradict these conclusions. In particular, these current results suggest that optimal delivery rate varies with stimulus information to yield a constant peak IT rate that depends on the degree of familiarity and training with a particular stimulus set. We discuss factors that may be responsible for the discrepancies in results across studies including procedural differences, training issues, and stimulus-response compatibility. These factors should be taken into account when designing haptic signals to yield optimal IT rates for communication devices.