Does the view of your nose help your smell?

Vision of one’s own body part can improve tactile sensitivity on that body part (Serino et al, 2009). Here, we verified whether seeing one’s own nose could facilitate odour detection, and eventually whether this effect could affect the olfactory and the trigeminal systems differently. Therefore, we presented 21 people (12 females) with an odour detection task by presenting through an olfactometer a series of stimuli (banana as odorant, mint as trigeminal stimulus, and clean air as control) while viewing on a PC monitor different pictures: Their own nose, a body-unrelated object (a kitchen hood), and a black square as control. On each trial, participants were instructed to try and detect the presence of odours as fast and accurately as possible. The results revealed that detection of the odorant was less accurate (M=85%) than both trigeminal stimulus and clean air (for both, M=97%). Overall, responses to clean air were significantly longer (M=1954 ms) than to trigeminal and odorant stimuli (M=1519 ms and M=1676 ms, respectively; cf. Jacob & Wang 2006). Interestingly, the interaction between odours and pictures was significant. As a matter of fact, responses to trigeminal stimuli were faster than those to odorant trials in both the control (M=1553 ms and M=1681 ms, respectively) and body-unrelated condition (M=1448 ms and M=1708 ms, respectively), while there was no difference in the body-related condition. This last result might be due to a possible distracting effect exerted by the nose picture which could have somewhat slowed down the responses to trigeminal trials.