The unconscious and smells
Today we know that the sense of smell has a crucial importance in our lives.
The imprint of smells on the human unconscious
Like Gregory Samsa, Stephen D. woke up one fine day having undergone a metamorphosis. That morning, possibly due to the recent consumption of amphetamines, the smell took over his entire perceptual world.. And this was what defined this young man's life for the next few days: an incredible sensitivity to scents. The exaltation of his sense of smell meant that all he noticed around him were fragrant notes and, although he retained the rest of his senses, they all seemed to have lost importance under the rule of the nasal.
For the first time, Stephen D. had the need to smell everything, he identified people by their smell before seeing them and recognized the moods of his companions without looking at them. Not only did he become much more sensitive to all smells: all layers of the real became very powerful olfactory stimuli. Moreover, this metamorphosis also meant entering a reality in which a strong emotionality tinged everything. a strong emotionality tinged everythingThe here and now came to the forefront while abstract thought was dwarfed as it dissolved in this rich array of sensations.
Sadly, after three weeks everything returned to normal. The loss of this gift, as abrupt as its arrival, was an emotional shock. Once the door to a world of such pure perception had been opened, it was difficult to give up these sensations.
These events, recounted by Oliver Sacks in a chapter called The Dog Under the Skinare presented as true by the author (Sacks, 2010/1985). To most of us, however, this may seem like an almost alien account, something that bears little or no relation to our everyday experience. We generally believe that smell is something like the poor brother of the five senses, we think of smell as something of a poor brother to the five senses.. This is true to a certain extent.
Smell, emotionality and the unconscious
Our whole life seems to have audiovisual formatOur leisure time, the people we interact with and the situations we are involved in are defined by what we can see and hear. However, the story of Stephen D. has a particularity that calls this rule into question: this young man sees his sensitivity to smells increase due to the effects of a drug, but the major structures of his body do not undergo any transformation.
Neither his nose enlarges nor his brain transforms into that of a dog, and the changes come and go very quickly, suggesting that they are due to a relatively superficial alteration. Simply put, his nervous system functions differently for three weeks on top of the brain mechanisms already in place.
Perhaps it is all explained by the fact that, in Stephen's case, some processes that normally remain unconscious made the leap to consciousness. Perhaps, even if we don't realize it, we all have a dog under our skin, an unconscious part of us that reacts to smells beyond our control.
Scientific evidence seems to support this perspective. We now know that the sense of smell plays a crucial role in our lives even though we may not realize it. For example, smell has been found to be a very powerful trigger of memories associated with each of the fragrances, and that this happens independently of our will to remember something. Moreover, the experiences that odors bring to our memory are of a much more emotional character than memories evoked by images or words (Herz, R. S., 2002). This is true for a wide variety of odors.
However, perhaps the most interesting repertoire of reactions we have to odor is when that odor comes from another human being. In the end, the information provided by other people is as important, if not more important, than that provided by a ripe pear, a mowed lawn, or a plate of macaroni. If we want to understand how odor-based communication between people works, we have to talk about pheromones and signature odors.
Invisible communication
A pheromone is a chemical signal emitted by one individual that alters the behavior or psychological disposition of another individual (Luscher and Karlson, 1959). They are species-specific chemical signals that produce instinctive reactions. Signature odors, on the other hand, serve to identify each specific member of the species and are based on the recognition of previously experienced odors (Vaglio, 2009). Both are ubiquitous in many life forms, and humans seem to be no exception.
Although the human species is not as sensitive to odors as other mammals (a sign of this is that our snout is drastically flattened, giving rise to fewer olfactory receptors), our body is capable of know aspects of other people such as 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 showed how people can become emotionally synchronized with each other. emotionally synchronized through the smell they emit. During the experiment, a series of men were exposed to two types of film: one was scary, and the other showed repulsive images. While this was going on, sweat samples were collected from these participants (overall, it must have been quite an unsettling experience). Once this was done, these sweat samples were exposed to a group of female volunteers and their reactions were recorded: those who smelled sweat secreted during the viewing of the scary movie showed a facial gesturing associated with fear, while the face language of those who smelled the other samples expressed disgust (de Groot et al, 2012).
Despite this, it is possible that the most important property of these odor traces is their ability to influence our reproductive behavior. Olfactory acuity in both males and females increases upon reaching puberty (Velle, 1978), and in the case of females this ability to perceive odors fluctuates with their menstrual cycle (Schneider and Wolf, 1955), so that the relationship between sexual behavior and olfaction is evident. It seems that men and women judge the attractiveness of people in part by their smell, since this provides relevant information about the internal state of our bodies, an area about which sight and hearing cannot give us much (Schaal & Porter, 1991).
Females, for example, seem to tend to prefer mates with a different repertoire of immune responses than their own, perhaps in order to produce offspring with a good antibody repertoire (Wedekind, 1995), and are guided by olfaction to receive this type of data. Beyond mate searching, moreover, mothers are able to differentiate the signature odor of their babies two days postpartum (Russell, 1983). Infants, for their part, are able to recognize their mother by smell as early as the first months of life (Schaal et al, 1980).
The explanation
How is it possible that smell influences our behavior so much without our noticing it? The answer lies in the disposition of our brain. It should be noted that the parts of the brain responsible for processing information about the chemical signals that surround us are very old in our evolutionary history, and therefore appeared long before the structures associated with abstract thought. Both smell and taste are directly connected to the lower part of the limbic system. lower part of the limbic system (the "emotional" area of the brain), unlike the other senses, which first pass through the thalamus and are therefore more accessible by conscious thought (Goodspeed et al, 1987) (Lehrer, 2010/2007).
For this reason the chemical signals we receive through the nose act drastically on the regulation of emotional toneThis is why odors are a unique way to influence the mood of people even if they do not realize it. Moreover, since the limbic system includes the hippocampus (a structure associated with memories), the signals picked up by the nose easily evoke experiences already lived, and they do so with a strong emotional charge accompanying this memory..
All this means, by the way, that theoretically some kind of manipulation could be exercised. manipulation 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, to be found in bakeries. Let us hope that it will take the big manufacturers of televisions and computers a little longer to discover it.
Bibliographical references:
- de Groot, J. H. B., Smeets, M. A. M., Kaldewaij, A., Duijndam, M. J. A. and Semin, G. R. (2012). Chemosignals Communicate Human Emotions. Psychological Science, 23(11), pp. 1417 - 1424.
- Goodspeed, R. B., Gent J. F. and Catalanotto, F. A. (1987). Chemosensory dysfunction: clinical evaluation results from a taste and smell clinic. Postgraduate Medicine, 81, pp. 251 - 260.
- Herz, R. S. y Schooler, J. W. (2002). A naturalistic study of autobiographical memories evoked by olfactory and visual cues: testing the Proustian hypothesis. American Journal of Psychology, 115, pp. 21 - 32.
- Luscher, M y Karlson, P. (1959). "Pheromones": a new term for a class of biologically active substances. Nature, 183, pp. 55 - 56.
- Russell, M. J. (1983). Human olfactory communications. En D. Müller-Schwarze y R. M. Silverstein, (Eds.), Chemical Signals in Vertebrates 3. Londres: Plenum Press.
- Sacks, O. (2010). El hombre que confundió a su mujer con un sombrero. Barcelona: Anagrama. (Originalmente publicado en 1985).
- Schaal, B., Motagner, H., Hertling, E., Bolzoni, D., Moyse, R. y Quinchon, R. (1980). Les stimulations olfactives dans les relations entre l'enfant et la mere. Reproduction Nutrition Development, 20, pp. 843 - 858.
- Schaal, B. y Porter, R. H. (1991). "Microsmatic Humans" revisited: the generation and perception of chemical signals. Advances in the Study of Behavior, 20, pp. 474 - 482.
- Schneider, R. A. y Wolf, S. (1955). Olfactory perception thresholds for citral using a new type of olfactorium. Applied Physiology, 8, pp. 337 - 342.
- Vaglio, S. (2009). Chemical communication and mother-infant recognition. Communicative & Integrative Biology, 2(3), pp. 279 - 281.
- Velle, W. (1978). Sex differences in sensory functions. Psychological Bulletin, 85, pp. 810 - 830.
- Wedekind, C., Seebeck, T., Bettens, F. y Paepke, A. J. (1995). MHC-dependent mate preferences in humans. Proceedings of the Royal Society of London B, 260, pp. 245–249.
(Updated at Apr 13 / 2024)