Olfactory sexual inhibition and the Westermarck effect

The Westermarck effect (sexual inhibition among individuals raised together ) is argued to be mediated olfactorily. Various animals, including humans, distinguish among individuals by scent (significantly determined by MHC gen otype), and some avoid cosocialized associates on this basis. Possible mode ls of olfactory mechanisms in humans are evaluated. Evidence suggests avers ions develop during an early sensitizing period, attach to persons as much as to their scents, and are more powerful among females than among males. A dult to child aversions may develop similarly, but more likely result from stimulus generalization. This hypothesis accords with current evidence and yields testable predictions (e.g., anosmia will prevent inhibition) that, s hould they be supported, will conclusively ground the Westermarck effect in a biological mechanism.