An American study published in the journal Psychological Science indicates that so-called "subliminal smells", ones that are not consciously perceived by the brain because they derive from extremely minute quantities, play a key role in our evaluation of a fellow human being (drawn face in this test) and bear more impact actually than consciously perceived smells.......
Curiously, according to the account of the study in the Telegraph, it seems that the categories of judgment related to types of smells in these tests are rendered very conventional and seem to coincide with conformist social judgment. Subliminally dosed Lemon is good, subliminally dosed BO is bad when looking at a neutral 2D face. Other studies show that different types of BOs emanating from real persons elicit different types of reactions according to the persons who perceive them and their genetic makeups (cf. studies on how the pill reverses perception of genetic info conveyed by BO).
"Now a study has revealed that faint odours that we are unaware of can influence whether we like the look of someone, so that the faintest hint of body odour can make a man appear less likeable. Most fascinating of all, it concludes that barely perceptible scents affect us more than an obvious smell, whether of BO or perfume."
Image from Psychnews