Passage AIntroduction: The sense of smell is powerful. Odours affect us on a physical, psychological and social level. For the most part, however, we breathe in the aromas which surround us without being consciously aware of their importance to us. It is only when the faculty of smell is impaired for some reason that we begin to realise the essential role the sense of smell plays in our sense of well-being. A survey conducted at Montreal's Concordia University asked participants to comment on how important smell was to them in their lives. It became apparent that smell can evoke strong emotional responses. A scent associated with a good experience can bring us joy, while an odour associated with a bad memory may disgust us. Respondents to the survey noted that many of their olfactory (嗅觉的) likes and dislikes were based on emotional associations. Such associations can be powerful enough so that odours that we generally label unpleasant become agreeable, and those that we consider fragrant become disagreeable for particular individuals. The perception of smell, therefore, consists not only of the odours themselves, but of the experiences and emotions associated with them.Similarly, odours are essential in social bonding. One participant in the survey believed that there is no true emotional bonding without touching and smelling a loved one. In fact, infants recognise the odours of their mothers soon after birth and adults can often identify their children or spouses by scent. In one well-known test, women and men were able to distinguish by smell alone clothing worn by their partners from similar clothing worn by other people. Most of the subjects would probably never have given much thought to odour as a cue for identifying family members before being involved in the test, but as the experiment revealed, even when not consciously considered, smells register.In spite of its importance to our emotional and sensory lives, smell is probably the most undervalued sense in many cultures. It is often held that the human sense of smell is undeveloped compared with that of animals. While the olfactory powers of humans are nothing like as fine as those possessed by certain animals, they are still remarkably acute. Our noses are able to recognise thousands of smells, and to perceive odours which are present only in extremely small quantities.Smell, however, is a highly elusive phenomenon. Odours, unlike colours, for instance, cannot be named in many languages because the specific vocabulary doesn't exist. 'It smells like…., ' we have to say when describing an odour, struggling to express our olfactory experience. Nor can odours be recorded: there is no effective way to either capture or store them over time. We must make do with descriptions and recollections. Most of the research on smell to date has been of a physical scientific nature. Significant advances have been made in the understanding of the biological and chemical nature of olfaction, but many fundamental questions have yet to be answered. Researchers have still to decide whether smell is one sense or two. Other unanswered questions are whether the nose is the only part of the body affected by odours, and how smells can be measured objectively given the nonphysical components. Questions like these mean that interest in the psychology of smell will play an increasingly important role.1. According to the introduction, we become aware of the importance of smell when __________.