Attention to olfaction - A psychophysical investigation

Olfaction is unique among the senses in that signals from the peripheral se nsory receptors bypass the thalamus on their way to the cortex. The fact th at olfactory stimuli are not gated by the thalamus has led some researchers to suggest that people may be unable to selectively direct their attention toward the olfactory modality. We examined this issue in an experiment whe re participants made speeded intensity (strong vs weak)discrimination respo nses to an unpredictable sequence of olfactory and visual stimuli. Attentio n was directed to either olfaction or to vision by means of an informative cue that predicted the likely modality for the upcoming target on the major ity of trials. Participants responded more rapidly when the target was pres ented in the expected rather than the unexpected modality, showing that peo ple can selectively attend to olfaction.