Inattentional numbness and the influence of task difficulty

Abstract

Research suggests that clearly detectable stimuli can be missed when attention is focused elsewhere, particularly when the observer is engaged in a complex task. Although this phenomenon has been demonstrated in vision and audition, much less is known about the possibility of a similar phenomenon within touch. Across two experiments, we investigated reported awareness of an unexpected tactile event as a function of the difficulty of a concurrent tactile task. Participants were presented with sequences of tactile stimuli to one hand and performed either an easy or a difficult counting task. On the final trial, an additional tactile stimulus was concurrently presented to the unattended hand. Retrospective reports revealed that more participants in the difficult (vs. easy) condition remained unaware of this unexpected stimulus, even though it was clearly detectable under full attention conditions. These experiments are the first demonstrating the phenomenon of inattentional numbness modulated by concurrent tactile task difficulty.

It's All in the Timing: Principles of Transient Distraction Illustrated with Vibrotactile Tasks

“…First, the auditory surprise distractor effects were consistently modest, when present at all. Such smaller effects are consistent with other studies of cross-modal attention distraction [19,31,49,50,60]. Second, there was little evidence of effects in the 1050 ms SOA, either positive or negative.…”

“…Another example is found in the inattentional numbness phenomenon. When one is paying attention to a demanding visual or tactile task, a strong but unexpected vibrotactile stimulus is often not detected [49,50].…”

“…For descriptive statistics, we report marginal means and standard deviations or standard errors of the mean. Before calculating descriptive and inferential statistics for the sample, we removed participants whose detection performance in target-only trials was not reliably above chance performance, a procedure used in similar studies [49][50][51]. We reasoned that we could not assess the effects of surprise distractors on performance from such individuals.…”

“…Instead of detecting specific distracting events, the system could instead detect when the user is in a taxing environment or a taxing attentional state [5,29,44,46,49,50,54]. In such cases, information that is important but does not require immediate action (e.g.…”

Examining the efficacy of vibrotactile displays for monitoring patient vital signs: Six laboratory studies of change detection and state identification.

“…Moreover, Gomes, Betza, et al (2020) found that tacton detection was lower when participants were standing and walking than when sitting. Instances of tactile change blindness (Lu & Sarter, 2014; Riggs & Sarter, 2016) and “inattentional numbness” have also been reported (Murphy & Dalton, 2016, 2018).…”