Human beings seem to have five key senses, these being sight, hearing, touch, taste and smell. Certain individuals may suggest humans have more senses than previously believed, however, the core five senses seem to remain undisputed. Certain senses may be closely linked such as the connection between an individual’s sense of smell and their sense of taste. This connection is largely due to their connection in the chemosensory system, or as it may be known, the chemical senses. A human’s ability to smell seems to be the result of specialised sensory cells within the olfactory system known as olfactory sensory neurons. This sensory system may be found within the nose and seems to connect cells to the brain, a process which may be found in several animals. It seems to be widely believed animals have a greater sense of smell when compared to humans, however, a recent study claims this may be a myth. An individual’s sense of smell seems to play a large role in the daily operation of many people from the aromatic scent of freshly cut grass to identifying which foods are still fresh enough to eat. A study from neuroscience professor John McGann claims humans may have a significantly stronger sense of smell than previously believed.
John McGann has been studying the olfactory system for the past 14 years and seems to have an intriguing hypothesis. During this time McGann examined existing data and historical writings, which may have made questionable claims regarding a human’s sense of smell and the potency of the olfactory bulb. The olfactory bulb is a rounded mass of tissue which houses several types of nerve cells, which form a sense of smell. The original myth regarding the power of human’s sense of smell seems to have been perpetuated in the 19th century by a brain surgeon and anthropologist by the name of Paul Broca. Paul Broca theorised humans have a smaller volume of olfactory receptors, – around 400, – where animals such as mice have close to 1000. This primary difference in the number of receptors in the nose seems to have largely contributed to this belief. This seems to have been supported by Broca’s writings in 1879 which claim this smaller olfactory area when compared to the brain, meant humans naturally were far from developed to rely on this sense when compared to other mammals and their reliance on smell for survival.
McGann suggests there may be more to a human’s sense of smell than previously hypothesised since this theory assumes humans and animals have the same sense of smell. McGann adds “Dogs may be better than humans at discriminating the urine on a fire hydrant and humans be better than dogs at discriminating the odours of fine wine, but few such comparisons have actual experimental support”. McGann suggests humans are believed to have a superior sense of smell seems to be due to them having a larger number of receptors in the nose. Human’s smell seems to affect behaviour, elicit memories, emotions and shape perceptions. This important sense seems to play a role in how individuals perceive the world and sometimes this may even be unconscious. From assisting when deciding what to eat to selecting mates the olfactory system of a human may be significantly more complex than previously believed. John McGann’s hypothesis into the complexity of the olfactory system may encourage further research in this area as more is learned about the importance of smell and the broad spectrum it may cover.
How might this recent study highlight the importance of one of humanity’s primary senses?