Motivation and emotion/Book/2013/Smell and emotion
Smell and emotion: How does smell affect emotion?
Have you ever wondered why the smell of lavender and talcum powder remind you of your grandmother? Or why smelling smoke makes you feel scared? Extensive research suggests that smell has a powerful link to our emotions and moods and can even influence how we perceive people and the world around us. Smell and emotional processes are uniquely linked through the limbic system in the brain which allows smell to have a strong influence on our emotions. Smell has the ability to change our emotions - both enhancing and reducing them - as well as regulate our mood. Chemosignals released by our bodies provide unconscious cues which give away how we are feeling and also have the potential to create the same emotion in others around us. In addition, it is becoming quite clear that smell plays a big part in our social relationships - dictating both who we befriend and our opinions of others. Smell is also quite a powerful trigger for emotional memories and these memories are far more potent than those elicited by our other senses. With all this in mind, there are ways we can use our sense of smell to improve our lives.
Smell is thought to be the least important of the five senses and is quite often called the “mute sense”. However, it is a common opinion among many researchers that the power of this sense is greatly underestimated. Olfaction is the term used to describe the function of perceiving odours. It is considered a chemical sense, as odours are said to be chemical substances - sometimes referred to as chemosignals (Soudry, Lemogne, Malinvaud, Consoli & Bonfils, 2011; Zhou & Chen, 2011). Olfaction is also the first of our five senses to completely mature in infancy (Angier, 2008).
Dysosmia is defined as an impairment or dysfunction in olfactory processing and results in an impaired or altered sense of smell. The main causes of dysosmia include head trauma, nasal blockages, migraines, nasal obstruction or infection, neurological damage and sometimes asthma. Some psychological disorders such as schizophrenia have also been linked to dysosmia (Kalogjera & Dzepina, 2012).
There are a few different classifications of dysosmia including anosmia, hyposmia, hyperosmia, parosmia and phantosmia.
Anosmia & hyposmia
Anosmia is a complete inability to detect odours, whereas hyposmia is a reduced ability to detect odours (Kalogjera & Dzepina, 2012).
Hyperosmia is a heightened sense of smell or “super-smell”. It is quite rare and difficult to diagnose (Leung, 2012).
Parosmia & phantosmia
Parosmia is a distorted perception of odours. Most often it involves perceiving pleasant or neutral odours as unpleasant. Put simply, phantosmia is olfactory hallucination, smelling odours that aren’t there, or “phantom smells” (Kalogjera & Dzepina, 2012).
Defining emotion and mood
Unfortunately there are no simple, definitive phrases to explain emotion and mood. Emotion can be described as a strong, short lived response to a stimulus (Pepe, Sims & Chin, 2007). Human emotions are conveyed through facial expression, body language, tone of voice, and even body odors (Zhou & Chen, 2011). Mood on the other hand, is described as a less intense, enduring response to a stimulus (Pepe, Sims & Chin, 2007).
There are many theories proposed to explain the processes behind emotion and emotional reactions. Basic emotion theories state that there are a handful of primary emotions which people experience and these can be further categorised as secondary emotions. The six agreed primary emotions are anger, disgust, fear, sadness, surprise and joy and provide broad terms to an array of secondary emotions. There is an almost endless number of secondary emotions including pride, hope, boredom, desire, disappointment, love, amusements, jealousy, admiration, irritation, etc. (Porcherot, 2010; Soudry et al., 2011).
Appraisal theories of emotion state that emotions are a result of a cognitive evaluation of a life event regarding its significance and relevance to our lives, as opposed to the event itself (Herzberg, 2009). For an example, when encountering a strange dog in the park, one could react excitedly and become happy, or fearfully and become anxious. Appraisal theory states that our emotional reaction is not brought on by the dog, but how we perceive the dog - perhaps the dog is a reminder of an angry dog encountered in our past, or of a friendly dog we owned as a child. Chrea et al. (2009) proposed that an appraisal theory of emotion would be more appropriate in explaining how smell is able to influence emotion as it allows for a more comprehensive conceptualisation of the interactions between major determining factors.
In order to fully understand how smell is able to affect emotion, it is important to examine the mechanisms involved receiving and perceiving odors and the brain structures which process olfactory and emotional information.
The olfactory system is unique in that it has direct contact to the limbic system in the brain (La Torre, 2003). When we breathe in, we inhale odorant molecules which pass through our nasal cavity to olfactory receptors located near the septum (Grammer, Fink & Neave, 2005; Soudry et al., 2011). These chemosignals are quite often unnoticeable and our olfactory system processes these at an unconscious level (Zhou & Chen, 2011). These signals travel through olfactory neurons until they reach the olfactory bulb, which is located in the limbic system.
The limbic system contains the thalamus, amygdala and hippocampus, among other structures, which are directly involved in the creation and processing of emotional information and memory (Masaoka, Sugiyama, Katayama, Kashiwagi & Homma, 2012) as well as the regulation of mood (Chu & Downes, 2000). The amygdala plays a crucial role in the detection of emotional signals, whereas the hippocampus is involved in memory creation and storage as well as responses to stress and creating context of emotional information (Soudry et al., 2011).
It is this closeness to brain structures which are essential in the creation, regulation and storage of memory, emotions and mood that leads researchers to believe that smell has a large role to play in eliciting emotion, changing and regulating mood and retrieval of and cues for emotionally charged memories.
Can we smell emotions?
The ability to smell someone’s emotions sounds like it could be a super power. However, as unbelievable as the concept is, we are all able to detect emotions using our noses. The idea that smell is a powerful emotional trigger is common across most cultures (Chrea et al., 2009). This is made possible by chemosignals which are unconsciously detected and processed in the olfactory system (Dooley, 2012; Rodriguez, 2012).
It is a relatively new area of research but it has to date received quite a bit of attention. Many studies have been conducted looking at our ability to correctly identify an emotion based on the smell of someone else’s sweat, many of which have shown that a person’s body odour does provide information about their current emotional state (Croy, Olgun & Joraschky, 2011). As humans, we are capable of detecting and interpreting emotional cues from body odour even when there is no other indication to of the emotions involved (Zhou & Chen, 2011). In addition, it has been shown that the ability to correctly identify emotions based on body odour increases with familiarity, i.e. de facto couples who have been together for a long period of time are better at sensing their partner’s emotions using their olfactory senses than strangers (Rodriguez, 2012). Zhou and Chen (2011) also found that even though partners could not accurately state whether a sweat sample belonged to their significant other or a stranger, their interpretation of the emotion associated with the sweat was more accurate when the sample came from their partner.
Certain emotions can also trigger different emotional reactions in other people. For example, Prehn-Kristensen et al. (2009) discovered that empathy could be elicited by smelling the sweat of people who were anxious. In their experiment, they exposed participants to sweat samples from both an anxious subject and one who had been on an exercise bike. Through observation of functional magnetic resonance imaging (fMRI), they were able to conclude that the sweat from anxious subjects activated areas of the brain in the participants which are primarily involved with empathy.
Emotional contagion is the idea that an emotion can be elicited by being in the presence of another person experiencing that emotion. One study collected sweat samples from men who watched either a movie that generated disgust or a horror movie. These samples were then given to women whose facial expressions were recorded upon exposure. The women who smelt the “disgust” sweat produced facial expressions associated with disgust, and those who smelt the “scared” samples, produced facial expressions associated with fear (Dooley, 2012). Studies have also seen that participants exhibit symptoms of anxiety when entering a dentist waiting room if the previous inhabitants suffered anxiety when attending the dentist. Another study also found that when a group of participants watched a horror movie, they released a chemosignal which resulted in a second group of participants watching a comedy movie in the same room showing increased anxiety (Hoover, K., 2011).
For more information about emotional contagion, see Emotional contagion
As well as inducing certain emotional responses, odour can also influence and enhance our moods. Research has shown that pleasant odours can induce positive moods, and unpleasant odours can induce negative moods (Porcherot et al., 2010). They also have the ability to reduce negative mood and enhance positive mood (Chrea et al., 2009). For example, Lehrner, Eckersberger, Walla, Pötsch, and Deecke (2000) found that ambient odour of orange reduced anxiety, improved mood and increased calmness in women patients in a dental office, compared with controls.
In addition to improving our moods, our ability to smell can have a detrimental effect on our well-being. People suffering from dysosmia often suffer from depressive disorders, anxiety and lower general quality of life in relation to safety, eating habits, and interpersonal relationships (Soudry et al., 2011). One sufferer of anosmia, Bonnie Blodgett, reported feeling lost, sad and disconnected. Further, a woman who suffers from hyperosmia stated that her sensitivity to smell restricts where she travels, where she eats and who her friends are (Leung, 2012). In their study on quality of life in anosmia patients, Smeets et al. (2009) found increased feelings of nervousness and depression, reduced energy levels, more limitations in social activities/interactions and a reduction in general health as well as significantly higher levels of depression ranging from mild to severe.
Bonnie Blodgett has authored a book called "Remembering Smell: A Memoir of Losing - and Discovering - the Primal Sense". For more information see www.gardenletter.com.
We are all guilty of avoiding the person who has particularly pungent body odour or is wearing too much perfume, but does our sense of smell actually have an influence on who we like and our opinions of people. Research says it does. There is strong evidence out there to suggest that odours we cannot consciously detect can be a deciding factor on our opinions of people, and also on certain social groups.
There is a growing body of literature which shows that when people are exposed to smells which elicit disgust, they give harsher social and moral judgments. To expand on this, Inbar, Pizarro and Bloom (2012) exposed participants to a commercially available ‘stink bomb’ while asking them to give likeability ratings to a number of social groups including homosexual men and women, heterosexual men and women, the elderly, African Americans and college students, with the distinct purpose of identifying changes in ratings of gay men. Their results showed that when exposed to the disgusting odour, average likeability ratings of gay men significantly decreased. They also noted that ratings of gay women decreased slightly.
Similarly, Dematte, Osterbauer and Spence (2007) aimed to determine whether olfactory cues influenced female participant ratings of facial attractiveness in males. They were exposed to four different odours – geranium (pleasant), male fragrance (pleasant), body odour (unpleasant) and rubber (unpleasant) – while viewing images of male faces. They found that females rated the male faces as less attractive when they were exposed to unpleasant odours, compared with pleasant or neutral odours.
In addition, Li, Moallem, Paller and Gottfried (2007) employed 39 undergraduate students to test whether subliminal odours had the ability to alter social preference. The participants were exposed to pleasant, unpleasant and neutral odors while being shown photographs of neutral faces and were asked to rate the likeability of said faces. Their results showed that the likeability ratings were lower for those exposed to an unpleasant odor, and higher for those exposed to a pleasant odour. They also noted that these effects disappeared when the odours were detected consciously by participants, showing that subliminal odours have the biggest influence.
Research suggests that smell is the most powerful trigger for emotional memory of all the five senses. In particular, it is said that smell is particularly good at triggering memories long forgotten, such as those from childhood (Chrea et al., 2009; Chu & Downes, 2002). Not only is it a powerful trigger, but it has also been found that memories evoked through smell are far more emotionally potent than others as confirmed by Masaoka et al. (2012) in their study which measured the strength memories triggered by certain perfumes.
For more information on how memory and emotion are linked, see Memory and emotion.
How smell can improve your life
The most obvious answer to how smell can improve our lives is hazard detection. Our ability to smell is vital in the detection of environmental hazards such as gas, smoke and rotten food, all of which can have detrimental effects on our health and well-being (Kalogjera & Dzepina, 2012). However, there are other ways in which smell can improve our lives. One finding which will help students world-wide is that smell can help aid recall. Several studies have shown that when a certain scent was present during study and consequent exams, students obtained higher results. For example, wearing a particular perfume both while studying and wearing the same perfume while sitting an exam (Schab, 1990).
Aromatherapy is an alternative treatment which is said to be quite successful. Essential oils are used in various cultures across the world for their healing properties. The use of essential oils in massage and therapy is widely used and found to be effective for inducing calm and relaxation in clients and patients (La Torre, 2003). La Torre (2003) discusses an example of a particular client with whom she was undertaking regular psychotherapy. Her client, Doreen, was having trouble getting to the root of her problems with anxiety and this was affecting her studies and her life in general. During one of their sessions, the scent of lavender was introduced to help her relax. This triggered memories of a lavender and rose candle Doreen used to own and consequently resulted in her delving into past memories and purchasing another of these candles for further use to help her relax. It also resulted in Doreen feeling more comfortable in opening up about problems in her past.
DID YOU KNOW..?
We are exposed to both subliminal and detectable scents everyday which are employed to alter our moods. Olfactory marketing is a method employed by many retailers to make shoppers happier, more relaxed, and more likely to spend their money! For more information, see the links below.
Many people disregard smell as being less important than the other four senses. As it turns out, smell does have a large impact on our emotions and can affect our everyday experiences - from influencing our moods to determining our social behaviour. There is compelling research evidence showing that smell is an influential and vital sense; essential for hazard reduction, social relationships and general well-being.
When things go wrong with our sense of smell, studies have shown that there are serious consequences associated with having no sense of smell or the ability of "super smell" that greatly impact your emotional wellbeing which in turn indicates that smell has quite a powerful influence on our emotions.
There have been various studies linking smell and memory, smell and emotion, and smell and attraction. However, the interactions between smell and emotion are still a relatively new area of study which definitely warrant further investigation.
Test your knowledge!
Angier, N. (2008, August 5). The nose, an emotional time machine. The New York Times. Retrieved from http://www.nytimes.com Chrea, C., Grandjean, D., Delplanque, S., Cayeux, I., Le Calve, B., Aymard, L., Velazco, M., Sander, D., & Scherer, K. (2009). Mapping the semantic space for the subjective experience of emotional responses to odors. Chemical Senses, 34, 49-62.
Chu, S., & Downes, J. (2000). Odour-evoked autobiographical memories: Psychological investigations of proustian phenomena. Chemical Senses, 25, 111-116.
Chu, S., & Downes, J. (2002). Proust nose best: Odors are better cues of autobiographical memory. Memory and Cognition, 30(4), 511-518.
Croy, I., Olgun, S., & Joraschky, P. (2011). Basic emotions elicited by odors and pictures. Emotion, 11(6), 1331-1335.
Dematte, M., Osterbauer, R., & Spence, C. (2007). Olfactory cues modulate facial attractiveness. Chemical Senses, 32, 603-610.
Dooley, R. (2012, August 11). Yes, you really can smell emotions. Forbes. Retrieved from http://www.forbes.com
Grammer, K., Fink, B., Neave, N. (2005). Human pheromones and sexual attraction. European Journal of Obstetrics, Gynecology and Reproductive Biology, 118, 135-142.
Herzberg, L. (2009). Direction, causation and appraisal theories. Philosophical Psychology, 22(2), 167-186.
Hoover, K. (2011). The scent of emotion, sex and evolution. Maturitas, 70, 1-2.
Inbar, Y., Pizarro, D., & Bloom, P. (2012). Disgusting smells cause decreased liking of gay men. Emotion, 12(1), 23-27. doi: 10.1037/a0023984
Kalogjera, L., & Dzepina, D. (2012). Management of smell dysfunction. Current Allergy Asthma Report, 12, 154-162.
La Torre, M. (2003). Aromatherapy and the use of scents of psychotherapy. Perspectives in Psychiatric Care, 39(1), 35-37.
Lehrner, J., Eckersberger, C., Walla, P., Pötsch, G., & Deecke, L. (2000). Ambient odor of orange in a dental office reduces anxiety and improves mood in female patients. Physiology & Behavior, 71(1-2), 83–86.
Leung, W. (2012, November 25). Can smell convey emotions? The Globe and Mail. Retrieved from http://www.theglobeandmail.com
Li, W., Moallem, I., Paller, K., & Gottfried, J. (2007). Subliminal smells can guide social preferences. Psychological Science, 18(12), 1044-1049
Masaoka, Y., Sugiyama, H., Katayama, A., Kashiwagi, M., & Homma, I. (2012). Slow breathing and emotions associated with odor-induced autobiographical memories. Chemical Senses, 37, 379-388. doi: 10.1093/chemse/bjr120
Pepe, H., Sims, V., & Chin, M. (2007). Applying the appraisal theory of emotion to human-agent interaction. Proceedings of the Human Factors and Ergonomics Society Annual Meeting 2007, 51:1491. doi: 10.1177/154193120705102205
Porcherot, C., Delplanque, S., Raviot-Derrien, S., Le Calve, B., Chrea, C, Gaureau, N., & Cayeux, I. (2010). How do you feel when you smell this? Optimization of a verbal measurement of odor-elicited emotions. Food Quality and Preference, 21, 938-947.
Prehn-Kristensen, A., Wiesner, C., Bergmann, T., Wolff, S., Jansen, O., Mehdorn, H., Fersti, R., & Pause, B. (2009). Induction of empathy by the smell of anxiety. Plos One, 4(6), 1-9.
Rodriguez, T. (2012, December 31). Partners can smell each other’s emotions. Scientific American. Retrieved from http://www.scientificamerican.com
Schab, F. (1990). Odors and the remembrance of things past. Journal of Experimental Psychology: Learning, Memory and Cognition, 16(4), 648-655
Smeets, M., Veldhuizen, M., Galle, S., Gouweloos, J., de Haan, A. M., Vernooij, J., Visscher, F., & Kroeze, J. (2009). Sense of smell disorder and heath-related quality of life. Rehabilitation Psychology, 54(4), 404-412. doi: 10.1037/a0017502
Soudry, Y., Lemogne, C., Malinvaud, D., Consoli, S., & Bonfils, P. (2011). Olfactory system and emotion: Common substrates. European Annals of Otorhinolaryngology, Head and Neck Diseases, 128, 18-23.
Zhou, W., & Chen, D. (2011). Entangled chemosensory emotion and identity: Familiarity enhances detection of chemosensorily encoded emotion. Social Neuroscience, 6(3), 270-276.