Tactile “Change Blindness” in the Detection of Vibration Intensity

A variety of data rich complex domains stand to benefit from the introduction of tactile displays that offload the visual and auditory information channels. Yet, a better understanding of factors that affect tactile information processing is needed to ensure the robustness of these interfaces. Recent research has shown, for example, that the sense of touch can be affected by phenomena that are analogous to visual change blindness, which describes the surprising difficulty in detecting changes to a visual scene when these changes coincide with masking stimuli or blank inter-stimulus intervals. To date, tactile change blindness has been demonstrated only for changes in the number of body locations where vibrations were presented. The present study examined whether change blindness is observed also in the context of detecting changes in vibration intensity and whether the introduction of a secondary task during vibrotactile presentations exacerbates these effects. The findings show that a 300-ms vibrotactile masking stimulus and a 600-ms “mudsplash” sequence of stimuli significantly degrade performance in detecting coincident intensity changes, as do intensity changes that occur gradually instead of abruptly. Change detection was significantly worse in dual-task (vs. isolation) conditions for only the “mudsplash” presentations. Implications of these effects for the design of tactile displays that encode information in vibration intensity are discussed.