Vision of the body increases interference on the somatic signal detection task

Research suggests that attention has a significant effect on somatic perception in both healthy people and those who suffer from somatic disturbance. The current study investigates the effects of attending to the body on somatic awareness and a particular type of somatic disturbance: erroneous reports of touch sensation, as measured by the Somatic Signal Detection Task (SSDT). During the SSDT, participants are required to detect near-threshold tactile stimulation at their fingertip. Previous research has found that healthy participants erroneously report touch sensations in the absence of a stimulus on this task and that such false alarms are increased when a simultaneous light flash is presented next to their fingertip. Thirty-seven participants completed the SSDT under two conditions: non-informative vision of the hand and no vision of the hand. False alarms were significantly higher in light trials in the non-informative vision condition compared to light trials in the no-vision condition. However, hit rates, sensitivity (d') and response criterion (c) were not affected by non-informative vision of the hand. Using the SSDT, we found that viewing the body increased somatic interference, possibly due to raised awareness of internal bodily sensations. This work provides evidence that viewing the body can have a detrimental effect on simple detection of near-threshold tactile stimulation.