Olfaction or the sense of smell is perhaps the most crucial human senses that can influence our cognition, emotion, attitude, and behavior.
Olfaction: The sense of smell
Our sense of smell is often considered to be one of the most mysterious out of our five senses. Smell has played a vital role in ensuring our survival throughout our evolution. It is only through our ability to differentiate thousands of unique scents and odors we are able to identify a threat and realize when we are safe.
Guinness World Record holder, endurance athlete and author Christopher Bergland writes “Smell is often the first warning of safety or danger, friend or foe. Smells have the power to drive your behavior on an instinctive and subconscious level. Luckily, you can also harness the power of smell and consciously use it to your advantage.”
Unfortunately, most of us tend to underestimate the importance of smell. Olfaction is a physical sensation that can regulate our mental experiences. It can evoke psychological states of mind, both negative and positive, and trigger instantaneous reflexes. It can subtly influence our thoughts and emotions even when we are not aware of the scents in our present environment.
Why smell is so important
According to Fifth Sense, a charity for individuals affected by olfactory disorders, our olfactory neurons generate an impulse when it detects a smell. The olfactory nerve passes the impulse to a part of the brain known as the olfactory bulb. Here the signal is processed and passed on to related areas of the brain. This is collectively called the limbic system.
The Fifth Sense explains that “The limbic system comprises a set of structures within the brain that are regarded by scientists as playing a major role in controlling mood, memory, behaviour and emotion.” The Khan Academy adds that “The limbic system is a set of structures in the brain that deal with emotions and memory.” This helps us to realize why smell is so important when it comes to managing our mood, memories and emotions.
Scents and psychology
Our sense of smell is an evolutionary tool and all creatures from single-celled bacteria to bloodhounds can identify chemicals around them. The American Psychological Association (APA) explains “Odors are molecules, after all, and olfaction is just the vertebrate version of chemical sensing.”
But can smell affect our mood and behavior? Rachel S. Herz, an assistant professor of psychology at Brown University and author of The Scent of Desire: Discovering Our Enigmatic Sense of Smell believes the answer is yes. She explains “Odors do affect people’s mood, work performance and behavior in a variety of ways but it isn’t because odors work on us like a drug, instead we work on them through our experiences with them.” An odor can create a response only when we have associated a past event with that smell first. This process is called associative learning, where one event is linked to another due to past experiences. Once the association is established, the linked event can generate a conditioned response in response to the original event.
Rachel adds “We know that the neurological substrates of olfaction are especially geared for associative learning and emotional processing. The olfactory bulbs are part of the limbic system and directly connect with limbic structures that process emotion (the amygdala) and associative learning (the hippocampus).” Due to this neurological reason, olfaction and odors can influence our emotions and mood.
A 2016 study revealed a significant role for olfactory stimulation in the alteration of cognition, mood, and social behavior. It found that fragrances such as perfumes and room fresheners can influence our psychophysiological activities. The study states “The sense of smell plays an important role in the physiological effects of mood, stress, and working capacity.” It adds “Fragrances directly and/or indirectly affect the psychological and physiological conditions of humans.”
How smell affects our mood
Our memories are stored in the part of the brain which processes scents and odors. Hence, scents can not only trigger our memories, but also influence our emotions, cognitive abilities and productivity as well. “Odour molecules flow to the limbic system in the brain, where feelings, moods, emotions, sexual behaviour and memory are processed,” says Karen Gilbert, perfumery expert and author of The Art and Craft of Fragrance.