Odorant-specific patterns of sniffing during imagery distinguish 'bad' and 'good' olfactory imagers.

There are large individual differences in the self-reported ability to form vivid olfactory mental imagery. Based on such self-reports, subjects have been classified as 'bad' or 'good' imagers. The present study examined whether a differential strategy in re-enacting the olfactomotor response during imagery may explain the dissociation between 'bad' and 'good' olfactory imagers. As previously reported, odor imagery was accompanied by sniffing. Although 'bad' and 'good' olfactory imagers did not differ in their overall sniffing volume, they used different strategies when re-enacting the motor component of olfaction during imagery. Particularly, as in real perception, 'good' but not 'bad' imagers generated bigger sniffs when imagining a pleasant smell compared with an unpleasant smell (P<0.02). Furthermore, preventing sniffing significantly hampered mental imagery of pleasant odors in 'good' but not 'bad' imagers (P<0.03). Taken together, these results suggest (i) the validity of the dissociation between 'bad' and 'good' olfactory imagers as revealed by self-report; (ii) that sniffing may be a causal factor in the creation of olfactory imagery; and (iii) that sniff measurements may serve as a reliable non-verbal tool in exploring individual differences in odor imagery.