The unconscious and smells

The imprint of odors on the human unconscious

Like Gregorio Samsa, Stephen D. woke up one fine day after undergoing a metamorphosis. That morning, probably due to recent amphetamine use, the smell has taken over the reins of its entire perceptual world. And that’s what will define the life of this young man over the next few days: an incredible sensitivity to aromas. The exhilaration of his sense of smell made all he noticed scent notes around him, and if he retained the rest of his senses, they all seemed to have lost importance under the empire of what was nasal.

For the first time, Stephen D. needed to smell everything, identify people by their scent before they saw them, and recognize the moods of his peers without looking at them. Not only has he become much more sensitive to all smells: all layers of reality have become very powerful olfactory stimuli. Moreover, this metamorphosis also meant stepping into a reality in which a strong emotivity has everything, Bringing the here and now to the fore as abstract thought faded as it dissolved into this rich range of sensations.

Unfortunately, after three weeks everything is back to normal. The loss of this gift, brutal though it was, was an emotional blow. Once the door was opened to such a world of pure perception, it was difficult to let go of these sensations.

These events, recounted by Oliver Sacks in a chapter titled The Dog Under the Skin, are presented as true by the author (Sacks, 2010/1985). However, for most of us, it may have seemed like an almost alien story, one that has little or nothing to do with our day-to-day experience. Usually, we believe the smell is something like that poor brother of the five senses. This is true to some extent.

Smell, emotivity and unconsciousness

Our whole life seems to have audiovisual format: Both our free time and the people we interact with and the situations we find ourselves in are defined by what we can see and feel. However, the story of Stephen D. has a peculiarity that challenges this rule: this young man sees his sensitivity to odors increase due to the effects of a drug, but the large structures of his body do not undergo any transformation.

Neither his nose enlarges nor his brain transforms into a dog’s, and the changes come and go very quickly, suggesting that they are due to a relatively superficial alteration. Simply put, your nervous system works differently for three weeks on the brain mechanisms that already exist.

Perhaps this is because, in Stephen’s case, certain processes that normally remain unconscious have come to make the leap to consciousness. Maybe, even if we don’t realize it, we all have a dog under our skin, an unconscious part of us reacting to smells beyond our control.

Scientific evidence seems to support this perspective. Today we know that smell is crucial in our lives even if we don’t realize it. For example, odor has been shown to be a very powerful trigger for Best regards associated with each of the scents, and that this occurs independently of our willingness to remember something. In addition, the experiences that smells bring to our memory are much more emotional than memories evoked by pictures or words (Herz, RS, 2002). It happens with a wide variety of smells.

However, it may be that the most interesting repertoire of reactions we have to smell occurs when this smell comes from another human being. After all, the information that other people give us is as important, if not more, than the information that a ripe pear, clippings or a plate of macaroni can give us. If we want to understand how smell-based communication between people works, we need to talk about it. pheromones and of signature smells.

invisible communication

A pheromone is a chemical signal emitted by an individual that changes the behavior or psychological disposition of another individual (Luscher and Karlson, 1959). These are chemical signals defined by each specific species and which produce instinctive reactions. The distinctive scents, in turn, serve to identify each particular member of the species and are based on the recognition of previously experienced scents (Vaglio, 2009). Both occur everywhere in many life forms, and the case of humans does not appear to be an exception.

Although the human species is not as sensitive to odors as other mammals (a sign of this is that our noses have been drastically flattened, resulting in fewer scent receptors), our bodies are able to know the aspects of others like their identity, their emotional state or other aspects of their psychology from these “traces” that we leave in the air.

For example, a 2012 study revealed how people can be emotionally synchronized through the smell they emit. During the experiment, a series of men were exposed to two types of films: one scary and the other showed disgusting images. During this time, sweat samples were collected from these participants (overall, this must have been a rather disturbing experience). Once done, these sweat samples were displayed to a group of female volunteers and their reactions were recorded: Those who smelled segregated sweat while watching the horror film showed a facial gesture associated with fear, while the facial language of those who felt the rest of the samples expressed disgust (de Groot et al, 2012).

However, it is possible that the most important property of these odor traces is their ability to influence our reproductive behavior. Olfactory acuity in men and women increases with puberty (Velle, 1978), and in the case of women, this ability to perceive odors fluctuates with their menstrual cycle (Schneider and Wolf, 1955), therefore the relationship between sexual behavior and smell It’s obvious. It seems that men and women judge the attractiveness of people in part by their smell, as it provides relevant information about the internal state of our body, an area that sight and hearing cannot provide us with. a lot (Schaal & Porter, 1991).

Women, for example, seem to tend to prefer couples with a repertoire of immune responses different from their own, perhaps to sire offspring with good antibody distribution (Wedekind, 1995), and are guided by smell. to receive this type of data. . Beyond finding a partner, in addition, mothers can tell their babies’ signature scent two days after childbirth (Russell, 1983). Babies, on the other hand, are already able to recognize their mother by smell from the first months of life (Schaal et al, 1980).

the explanation

How is it possible that the smell influences our behavior so much without us realizing it? The answer is available to our brain. It should be noted that the parts of the brain responsible for processing information on the chemical signals that surround us are very old in our evolutionary history, and therefore appeared long before the structures associated with abstract thought. The smell and taste are directly related to the lower limbic system (The “emotional” area of ​​the brain), unlike the rest of the senses, which first pass through the thalamus and are therefore more accessible to conscious thought (Goodspeed et al, 1987) (Lehrer, 2010/2007).

For this reason, the chemical signals that we receive through the nose act drastically on the emotional tone regulation, Although we don’t realize it, and that’s why smells are a unique way to affect people’s moods even if they don’t notice it. Moreover, as the hippocampus (structure associated with memories) is included in the limbic system, the signals picked up by the nose easily evoke lived experiences, and they do so by accompanying this memory with a great emotional charge..

All of this means, by the way, that in theory you could exercise some sort of handling on the rest of the people without them being able to do much to control their own feelings and psychological dispositions. The clearest example of this principle of manipulation is, of course, in bakeries. Hopefully, the big TV and computer manufacturers will take a little longer to figure it out.

Bibliographical references:

  • de Groot, JHB, Smeets, MAM, Kaldewaij, A., Duijndam, MJA and Semin, GR (2012). Chemosignals communicate human emotions. Psychological Sciences, 23 (11), pages 1417-1424.
  • Goodspeed, RB, Gent JF and Catalanotto, FA (1987). Chemosensory dysfunction: results of clinical evaluation from a taste and smell clinic. Postgraduate Medicine, 81, pages 251 to 260.
  • Herz, RS and Schooler, JW (2002). A naturalistic study of autobiographical memories evoked by olfactory and visual clues: testing the Proustian hypothesis. American Journal of Psychology, 115, pages 21-32.
  • Luscher, M and Karlson, P. (1959). “Pheromones”: a new term for a class of biologically active substances. Nature, 183, pages 55-56.
  • Russell, MJ (1983). Human olfactory communications. In D. Müller-Schwarze and RM Silverstein, (Eds.), Chemical Signals in Vertebrates 3. London: Plenum Press.
  • Sacks, O. (2010). The man who mistook his wife for a hat. Barcelona: Anagram. (Originally published 1985).
  • Schaal, B., Motagner, H., Hertling, E., Bolzoni, D., Moyse, R., and Quinchon, R. (1980). Olfactory stimulation in the relationship between the child and the mother. Development of Reproductive Nutrition, 20, p. 843 – 858.
  • Schaal, B. and Porter, RH (1991). Revisited “microsmatic humans”: generation and perception of chemical signals. Progress in the Study of Behavior, 20, pages 474-482.
  • Schneider, RA and Wolf, S. (1955). Citral olfactory perception thresholds by a new type of olfactory. Applied Physiology, 8, pages 337-342.
  • Vaglio, S. (2009). Chemical communication and mother-baby recognition. Communicative and Integrative Biology, 2 (3), p. 279 – 281.
  • Velle, W. (1978). Sexual differences in sensory functions. Psychological Bulletin, 85, pages 810-830.
  • Wedekind, C., Seebeck, T., Bettens, F. and Paepke, AJ (1995). MHC-dependent couple preferences in men. Proceedings of the Royal Society of London B, 260, pages 245-249.

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