Losing your touch? Sustained inattentional numbness for dynamic tactile events

It is now well-known that a lack of attention can leave people unaware of clearly-noticeable, long-lasting and dynamic stimuli, such as a visible person dressed as a gorilla (Simons & Chabris, 1999) or an audible person claiming to be a gorilla (Dalton & Fraenkel, 2012). However, the question of whether touch can ever be susceptible to such extreme inattentional effects remains open. Here, we present evidence across two experiments that the absence of attention can leave people ‘numb’ to the presence of a tactile stimulus that lasts for 3.5 seconds and moves across six different skin locations, establishing the new phenomenon of ‘sustained inattentional numbness’. The effect is particularly surprising in light of claims that tactile information processing is more direct than auditory or visual processing (e.g., Gregory, 1967) which would suggest that tactile awareness might not be open to attentional modulation of the type that we observe here. The findings also have important applied implications given the increasing prevalence of tactile warnings in everyday information delivery systems.