Tactile perception by mouth: Perceiving properties of objects when vision is impaired

The lips and tongue demonstrate similar or greater spatial acuity than the fingertips. Indeed, infants use the mouth to perceive properties of objects such as hardness, texture, and shape. In normal development, it is assumed that mouthing decreases in favour of increasingly advanced hand exploration patterns. However, anecdotal reports suggest that mouthing continues to serve a perceptual function when a person’s vision is abnormal. This study explored blind or visually impaired (BVI) adults’ self-reported use of mouthing to perceive properties of objects. We conducted semi-structured interviews with 20 BVI adults with visual acuities ranging from no light perception to 20/40. Data were analysed using content analysis to identify specific properties perceived by the mouth. Despite social norms that discourage mouthing, some BVI adults use oral tactile perception of texture, shape, temperature, and taste to better characterize objects. These findings suggest that compensatory behaviours using the mouth can support the rehabilitation of individuals with abnormal vision.