Odor - Behavioral Cues

Behavioral Cues

Odor perception is a complex process involving the central nervous system that can evoke psychological and physiological responses. Because the olfactory signal terminates in or near the amygdala odors are strongly linked to memories and can evoke emotions. The amygdala participates in the hedonic or emotional processing of olfactory stimuli. Odors can disturb our concentration, diminish productivity, evoke symptoms, and, in general, increase a dislike for a particular environment. Odors can impact the liking for a person, place, food, or product as a form of conditioning. Memories recalled by odors are significantly more emotional and evocative than those recalled by the same cue presented visually or auditorily. Odors can become conditioned to experiential states and when later encountered have directional influences on behavior. Doing a frustrating task in a scented room decreases performance of other cognitive tasks with the presence of the same odor. Nonhuman animals communicate their emotional states through changes in body odor and human body odors are indicative of emotional state.

Human body odors influence interpersonal relationships. Human body odors are involved in adaptive behaviors, such as parental attachment in infants or partner choice in adults. "Mothers can discriminate the odor of their own child, and infants recognize and prefer the body odor of their mother over that of another woman. This maternal odor appears to guide infants toward the breast and to have a calming effect." Body odor is involved in the development of infant–mother attachment and is essential to a child’s social and emotional development bringing feelings of security. Reassurance created by familiar parental body odors may contribute significantly to the attachment process.

How a man smells is critical for woman to find a lover. Body odor is a sensory cue critical for mate selection because it is a signal of immunological health. Women prefer men with major histocompatibility complex (MHC) genotypes and odor different than themselves especially during ovulation. Different MHC alleles are favorable because different allele combinations would maximize disease protection and minimize recessive mutations in offspring. Biologically females tend to select mates "who are most likely to secure offspring survival and thus increase the likelihood that her genetic contribution will be reproductively viable."

Studies have suggested that people might be using odor cues associated with the immune system to select mates. Using a brain imaging technique, Swedish researchers have shown that gay and straight males' brains respond differently to two odors that may be involved in sexual arousal, and that the gay men respond in the same way as straight women, though it could not be determined whether this was cause or effect. The study was expanded to include lesbian women; the results were consistent with previous findings meaning that lesbian women were not as responsive to male identified odors, while their response to female cues was similar to straight males. According to the researchers, this research suggests a possible role for human pheromones in the biological basis of sexual orientation.

An odor can cue recall of a distant memory. Most memories that pertain to odor come from the first decade of life, compared to verbal and visual memories which usually come from the 10th to 30th years of life. Odor-evoked memories are more emotional, associated with stronger feelings of being brought back in time, and have been thought of less often as compared to memories evoked by other cues.