Selective adaptation has been used to evaluate receptor specificity in olfaction on the assumption that exposure to 1 stimulus will inhibit or cross-adapt the olfactory system to similar stimuli. It is theoretically possible that a stimulus could also facilitate or enhance the sensitivity to another stimulus, although this has not been demonstrated. Evidence for such facilitation in odor detection measured as a change in the human neonate's respiration is shown. It is hypothesized that facilitation may be explained in terms of the solubility of the odorants. (PsycINFO Database Record (c) 2006 APA, all rights reserved)