Abstract
In many mammals, various social interactions are guided by olfactory cues, whereby olfactory preferences often form early in ontogeny. Early olfactory learning is usually investigated within the theoretical framework of olfactory imprint- ing, which assumes that early olfactory preferences are acquired upon a short expo- sure and with no need for further reinforcement. It is also expected that such preferences are resistant to change. Olfactory imprinting has been investigated using a cross-fostering experimental design or by early exposure to artifcial odours and subsequent assessment of preference for these odours. Existing fndings indicate that mammals develop olfactory preferences during a limited period of time in early postnatal development, and once acquired, these preferences remain stable at least until weaning. On the other hand, there is currently no evidence to the effect that juvenile odour preferences are acquired at the same time as adult odour preferences.
Stability of adult odour preferences also depends on the stimuli used in experiments, because some stimuli (e.g. natural odours) seem to elicit stronger preferences than others (e.g., artifcial odours). Moreover, some reinforcement is needed for early olfactory learning, which is why it is diffcult to disentangle the particular learning mechanisms involved. Despite the wide range of studies on the subject, it thus remains unclear what mechanisms underpin early odour learning.