The Importance of Smell: Perfuming Human Evolution

Throughout human history, the sense of smell has played fundamental roles in the survival, adaptation, and evolution of our species.

Although often underestimated, this sense is directly connected to deep areas of the brain responsible for emotional responses, memories, and social behaviors. But what, after all, was its evolutionary importance?

Survival and Risk Detection

Since the earliest hominids, the sense of smell was essential for detecting spoiled food, sources of danger like smoke and predators, and guiding movement in the natural environment.

Although we now live in urban and highly visual contexts, our brain still responds automatically and quickly to certain smells, especially those indicating a threat.

This rapid response occurs because the olfactory bulb, the first station for processing smells, has direct connections to the limbic system, bypassing the thalamus, which normally handles sensory mediation.

Therefore, the smell of something burning, for example, can trigger an alarm reaction even before we consciously identify what is happening.

The Complexity of Human Olfaction

A common misconception is that the human sense of smell is weak compared to other animals—an idea that originated in the 19th century but has since been widely refuted by contemporary studies.

Although the surface of our olfactory epithelium is smaller and we no longer possess a functional accessory olfactory system (the vomeronasal system, responsible for detecting pheromones in many mammals), our brain compensates for these differences with a significantly higher number of olfactory glomeruli in the bulb—about three times more than mice, for example.

Furthermore, the way we interpret smells is considerably more complex, involving regions of the limbic system related to memory, emotions, and social context.

In other words, for humans, a smell is never just a chemical signal—it is an experience shaped by the environment, culture, personal history, and emotional state.

Chemical Communication and Social Bonds

Long before verbal language was established as the primary form of communication, smells already served as invisible cues in social interactions. Even today, humans produce and perceive chemical signals that can influence emotional states and proximity between people.

For example, studies show we can distinguish a person’s emotions by their scent. These chemical signals, though subtle, are processed automatically and can make us feel more empathy, alertness, or comfort near someone—influencing social decisions without us even realizing it.

Partner Selection and Genetic Diversity

The sense of smell also plays a surprising role in sexual partner selection. Research indicates that body odor can provide clues about genetic compatibility between individuals, especially concerning the immune system (MHC – Major Histocompatibility Complex).

Unconsciously, people tend to prefer the scent of individuals with genes different from their own, which increases the chance of producing offspring with greater immunological diversity, resulting in higher resistance to diseases.

Additionally, men can perceive subtle changes in a woman’s scent during her fertile period, which may have influenced reproductive behaviors over time.

Smell as an Affective and Cognitive Compass

Throughout our lives, we form a veritable “emotional archive” of smells: those that calm us, those that alert us to risks, and those that connect us to important people. This helps us navigate the social and environmental world more efficiently, even unconsciously.

Furthermore, the sense of smell is often one of the first senses to develop and one of the last to deteriorate. This suggests a basal and persistent function throughout aging, reinforcing its role as a “guiding sense” in our brain—whether for protection or for affectivity.

The Pandemic and the Rediscovery of Smell

The loss of smell (anosmia) during the COVID-19 pandemic was a watershed moment in the public’s perception of this sense’s importance.

Many people came to value their sense of smell precisely when they realized the profound impact of its absence: the loss of pleasure in eating, emotional detachment, difficulties with personal hygiene, and even an increase in depressive symptoms.

This collective experience revealed that the sense of smell is far from dispensable; it influences our well-being continuously, even if silently.

Discover the Boticário Group’s Olfactory Research Center

Knowing the vital importance of this sense, Grupo Boticário created the Olfactory Research Center (Centro de Pesquisa do Olfato). This center fosters knowledge in the field of research on smell and its relationship with behavior and well-being, aiming to understand the sensations caused by odors. Through this, it contributes to the development of new fragrances, always taking sensory diversity into account.

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