Odors influence several aspects of life, such as thoughts, memories, decisions, and emotions. Numerous studies have shown that human behavior can be affected by odors in different contexts. One such context is social relationships, in which body odors play a role. For example, previous studies have shown that close family members can identify each other’s body odors and prefer these compared to the body odors of non-family members. However, further research is needed to establish how body odors and olfactory functioning affect interpersonal behaviors and intimate relationships. In this thesis, I have conducted three studies highlighting the interplay between intimate relationships and olfaction. The overall purpose of this thesis was to investigate if and how olfaction is related to behaviors in intimate relationships.

Study I tested if a romantic partner’s body odors have stress-altering effects and whether such effects differ depending on individual differences in romantic attachment security. As the practice of smelling a partner’s worn garment has been reported as a self-treatment against stress, my colleagues and I carried out an experiment to determine whether exposure to a partner’s body odor attenuates adult individuals’ subjective discomfort and psychophysiological responses. To induce discomfort and stress responses, participants were exposed to weak electric shocks while smelling their partner’s body odor (experimental condition) and three control odors (control conditions). The results showed that partner body odor had an attenuating effect on subjective discomfort during stress. Additionally, highly attachment-secure participants exhibited attenuated skin conductance specifically when exposed to their partner’s body odor. Thus, study I concluded that partner body odor is a scent of security, especially for relatively attachment-secure adults.

Next, to determine whether olfaction is linked to sexual outcomes in intimate relationships, study II explored associations between self-reported olfactory functioning, on the one hand, and infidelity and sexual well-being, on the other, using a survey design. Our exploratory analyses found that self-reported olfactory function predicted sexual well-being positively and infidelity negatively, while controlling for other relevant socio-demographic variables. These results are discussed from a relationship science perspective, in which one’s intimate partner signifies sexual bonding in addition to caregiving and attachment. Thus, study II suggests that a partner’s body odor might be a scent of monogamy.

Study III summarized the literature on populations with an impaired or total absence of a sense of smell. The interplay between olfaction and intimate relationship variables was examined by reviewing research reports and empirical studies concerning individuals with an impaired sense of smell. My colleague and I provided an overview of how olfactory impairment can impact three types of close social relationships: family relationships, friendships, and romantic relationships. For romantic relationships, which are the main focus of this thesis, three categories were defined in which olfactory impairment can impact close social relationships: eating, social support, and sexuality. Thus, study III concludes that olfactory ability is related to various romantic, intimate relationship behaviors.

In sum, all three studies reported findings highlighting that olfaction (body odors and olfactory functioning) is related to intimate relationships. The results from the three studies are discussed via theoretical frameworks concerning the sense of smell, romantic relationships, and attachment. The thesis concludes that olfactory functioning and the experience of body odors are meaningful for intimate relationships and, as such, also for various behaviors in these relationships.