Odorant identification in rats: an update.

In a previous report, Youngentob et al. (8) described a new and substantially different type of animal psychophysical procedure in which rats were trained to differentially report (i.e., identify) five different odorants. The present study confirms and extends the usefulness of the cross-modal association paradigm as an effective means for developing an extensive nonverbal "vocabulary" with which an animal can communicate multiple changes in sensory stimuli. Given the appropriate nonverbal means of communication, a rat has the channel capacity to differentially report (i.e., identify), at least ten different odorants. The expansion to a ten odorant identification task is discussed with respect to the analytic capabilities of the animal model for the study of olfactory quality perception.