The trace of smells on the human unconscious
Like Gregorio Samsa, Stephen D. woke up one fine day having undergone a metamorphosis. That morning, possibly due to recent amphetamine use, the scent took over his entire perceptual world. And this was what defined the life of this young man for the next few days: an incredible sensitivity to aromas. The exaltation of his nose made everything he noticed around him fragrant notes, and although he preserved 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 urge to smell everything, he identified people by their smell before he saw them, and he 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 were turned into by very powerful olfactory stimuli. In addition, this metamorphosis also meant entering a reality in which a strong emotionality colored everything, bringing the here and now to the fore, while abstract thought was dwarfed by dissolving into that rich range of sensations.
Unfortunately, after three weeks everything was back to normal. The loss of this gift, as abrupt as its arrival, and was a strong emotional blow. Once the door was opened to a world of such pure perception, it was difficult to renounce those sensations.
These events, narrated by Oliver Sacks in a chapter called The Dog Under the Skin, are presented as true by the author (Sacks, 2010/1985). However, to most of us, this may seem like an almost alien tale, something that bears little or no relation to our everyday experience. Usually, we believe that smell is something like the poor brother of the five senses. This is true up to a point.
Smell, emotionality and unconscious
Our whole life seems to have an audiovisual format: both our leisure time and the people with whom we interact and the situations in which we are involved are defined by what we can see and hear. However, the story of Stephen D. has a peculiarity that calls into question 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 is enlarged nor his brain becomes that of a dog, and the changes come and go very quickly, suggesting that they are due to a relatively superficial alteration. Your nervous system simply works differently for three weeks on existing brain mechanisms.
Perhaps everything is explained because, in Stephen’s case, some processes that normally remain unconscious came to make the leap towards consciousness. Perhaps, although we do not 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 view. Today we know that the sense of smell is of crucial importance in our lives even though we may not realize it. For example, the odor has been shown to be a very powerful trigger for regards associated with each of the fragrances, and that this happens regardless of our desire to remember something. Furthermore, the experiences that smell brings to our memory are of a much more emotional nature than the memories evoked by images or by words (Herz, RS, 2002). This occurs with a wide variety of odors.
However, perhaps the most interesting repertoire of reactions we have to smell is when that smell comes from another human being. At the end of the day, the information that other people provide us is as important, if not more, than what a ripe pear, mowed grass, or a plate of macaroni can provide. If we want to understand how communication between people based on smell works, we have to talk about pheromones and signature smells.
A pheromone is a chemical signal emitted by an individual and that alters the behavior or psychological disposition of another individual (Luscher and Karlson, 1959). They are chemical signals defined by each specific species and that produce instinctive reactions. Signature odors, meanwhile, serve to identify each specific member of the species and are based on the recognition of previously experienced odors (Vaglio, 2009). Both occur everywhere in many forms of life, and the case of humans does not seem to be an exception.
Although the human species is not as sensitive to odors as other mammals (an example of this is that our snout has flattened drastically, 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 found how people can become emotionally in sync through the smell they emit. During the experiment, a series of men were exposed to two types of film: one of them 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 secreted sweat during the viewing of the scary movie showed facial gestures associated with fear, while the language of The face of those who smelled the rest of the 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 men and women increases upon reaching puberty (Velle, 1978), and in the case of women, this ability to perceive odors fluctuates with their menstrual cycle (Schneider and Wolf, 1955), so the relationship between sexual behavior and smell It is obvious. 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 in which sight and hearing cannot contribute much (Schaal & Porter, 1991).
Women, for example, seem to tend to prefer partners with a different repertoire of immune responses than their own, perhaps to produce offspring with a good array of antibodies (Wedekind, 1995), and are guided by smell to receive this type of data. Beyond the search for a partner, in addition, mothers can differentiate their babies’ signature scent two days postpartum (Russell, 1983). Babies, on the other hand, from the first months of life are able to recognize their mother by smell (Schaal et al, 1980).
How is it possible that smell influences our behavior so much without us noticing it? The answer lies in the disposition of our brain. It must be taken into account that the parts of the brain in charge of 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 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 by 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 regulation of emotional tone, although we do not realize it, and that is why smells are a unique way to influence the mood of people even if they do not realize it. Furthermore, as 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 by accompanying this memory with a great emotional charge.
All this means, by the way, that theoretically some kind of handling over 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, found in bakeries. Hopefully, the big television and computer manufacturers will take a little longer to find out.