Can odours acquire fat-like properties?

Odours can acquire taste-like properties via simultaneous pairing in the mouth with tastants like sucrose. The experiment reported here sought to test whether qualities other than taste may also be acquired. Participants received pairings between odour A and low-fat unsweetened milk (LFUN), odour B and low-fat sweetened milk (LFSW), odour C and high-fat unsweetened milk (HFUN) and odour D and high-fat sweetened milk (HFSW). On test, participants reported that odours paired with milks perceived as being fattier (i.e. LFSW, HFUN, HFSW) were judged to smell fattier than they did prior to conditioning. In a further test, participants were asked to sample each of the four odours in a slightly fatty-sweet milk target. Odours previously paired with high-fat milks enhanced perceived fattiness of the target, whilst odours previously paired with sweetened milks enhanced perceived sweetness. These results were not well accounted for by participants' explicit knowledge of the odour-milk pairings and suggest that fat-like qualities may be acquired.