Behaviorally, at central sound positions (= auditory cues maximally ambiguous), participants were more likely to categorize a sound as coming from the right with concurrent right-nostril stimulation, while the proportion of left-responses increased with left-nostril stimulation.

Notably, this effect was only robust in the 2nd half of the sound sequence, suggesting an after-effect of odorant stimulation. Our results replicate a previous report of odorant-induced sound localization bias under slightly different conditions (Liang et al., 2022, Chem. Seses).