Latest scientific research is dismantling the myth that humans are “bad smellers,” revealing that our sense of smell is not only ancient but deeply intertwined with memory and emotion—a connection far richer than previously thought. This new understanding sheds light on how even a simple whiff of a familiar odor can instantly transport us back in time, evoking powerful memories and emotions, and opens the possibility of harnessing scents in therapeutic, educational, and cultural contexts in Thailand and beyond.
For years, smell was the neglected sibling of the senses, dismissed as less important or useful compared to sight and hearing. The assumption stemmed from 19th-century brain research by Paul Broca, who noted that human olfactory bulbs—the brain’s smell-processing regions—are relatively small compared to those of animals. Misinterpretations of Broca’s work led to the belief that humans are poor at smelling, a misconception that was repeated by figures like Freud and endured in popular culture and science for over a century (Quanta Magazine). Yet, contrary to these old ideas, emerging studies demonstrate that the human sense of smell is both sophisticated and central to how we experience the world.
Researchers now know that smell is our most ancient sense, tracing its roots back billions of years to the first cells that could sense chemicals in their environment. Prof. Matthias Laska, a leading zoologist at Linköping University, notes, “No single cell can see or hear. But single cells already can respond to chemicals.” In the 1990s, Nobel laureates Linda Buck and Richard Axel discovered the genes that code for odorant receptors, revealing that humans possess around 400 different kinds of these receptors, each capable of detecting a wide range of scent molecules. When we smell something as simple as a rose, hundreds of different molecules enter the nose, binding to millions of receptors and firing distinct patterns of neurons in the brain.
The profound link between smell, memory, and emotion is rooted in how the brain processes odors. The olfactory pathways connect directly to the limbic system, including the amygdala and hippocampus, which are responsible for emotion and memory. This connection explains why the smell of green tomatoes might send a leading German olfaction researcher instantly back to his childhood bedroom, and why many Thais might be reminded of a grandmother’s kitchen upon catching a whiff of jasmine rice or lemongrass. According to olfactory researcher Dr. Valentina Parma at the Monell Chemical Senses Center, “It’s a highly dimensional sense. We don’t know exactly how chemicals translate to perception.” But recent breakthroughs are beginning to close these gaps.
A number of new databases and scientific efforts are underway to build a common language for describing how specific molecules smell to humans. For example, a study published in Scientific Data details efforts to systematically catalog the odor profiles of thousands of molecules. Meanwhile, brain imaging and molecular studies, some published in Nature, are mapping how these molecular signals are “translated into a neural language” that produces recognizable memories and emotional reactions.
Understanding smells and how we talk about them is a central challenge. As Antonie Bierling of Dresden University of Technology points out, “We tend to underestimate our sense of smell because we lack a vocabulary for it.” While we can easily describe a pineapple as “yellow and green with scaly skin,” trying to articulate the actual smell of a pineapple is far more difficult. In English and even in Thai, smell words are often borrowed from their sources—“grassy,” “fishy,” or “jasmine-like”—limiting precise scientific analysis. Thai cuisine’s distinctive use of aromatic herbs such as lemongrass, kaffir lime leaves, and holy basil illustrates how well-developed olfactory preferences are deeply ingrained in the country’s culture, yet even here, precise descriptions remain challenging.
Recent studies emphasize that smells not only evoke memories but can also influence learning, mood, and cognitive performance. In hospitals, some research suggests that familiar or pleasant scents can reduce patient stress and promote healing. In educational settings, using subtle fragrances like lavender or peppermint may enhance attention and recall, though more large-scale, peer-reviewed research is needed to determine robust effects (Frontiers in Behavioral Neuroscience; NIH). For Thailand’s growing elderly population—almost 20% of the population as of 2024—the therapeutic use of scent (aromatherapy) is gaining traction in dementia care and mental health support programs.
In the context of Thai society, smells are integral to daily life and religious practice. From burning incense at Buddhist temples to the aroma of street food, scent forms part of the nation’s collective identity. The loss of smell, anosmia, which gained public awareness during the COVID-19 pandemic, has highlighted how crucial olfaction is to well-being and social connection. Public health campaigns in Thailand have since begun to recognize the importance of early detection and intervention for olfactory dysfunction, emphasizing smell tests alongside more traditional health screenings.
Culturally, Thai language and literature are rich in olfactory references, from classic poetry that evokes the scent of blooming champaca trees to modern advertisements that harness the allure of perfume or freshly cooked rice. Yet, the new research suggests that science is only beginning to catch up with art and tradition in appreciating the significance of smell.
Looking ahead, advances in olfactory science may help develop new diagnostic tools for diseases including Alzheimer’s, since changes in smell sensitivity can precede cognitive decline by years (Alzheimer’s Association). For Thai researchers and policymakers, investing in olfactory research and public education could lead to earlier disease detection, enhanced learning environments, and better quality of life for vulnerable populations. Furthermore, food tourism, a cornerstone of Thailand’s economy, can benefit from a deeper scientific understanding of how aroma shapes visitor experiences, potentially leading to innovative marketing and culinary initiatives.
As our scientific vocabulary for smells continues to grow, so will opportunities for innovation in art, medicine, and culture. Experts urge Thai educators to incorporate olfactory learning in classrooms, health professionals to recognize the value of smell in diagnostics and therapy, and for individuals to pay closer attention to the subtle scents that color their everyday experiences. As for scientific progress, the future promises richer databases, improved testing kits, and more personalized interventions related to scent.
For all Thai readers: actively notice the smells in your daily routine, and consider how certain aromas can improve well-being or evoke warm memories. Encouraging children to describe and appreciate local scents—from incense at temples to the fragrance of Thai basil—can enrich cultural heritage and enhance cognitive development. If you notice sudden changes in your ability to smell, consult medical professionals, as this can be an early warning sign of illness. Scientific advances are just beginning to decode the language of smell; in the meantime, appreciating and preserving Thailand’s distinctive aromas is both a comfort and an act of cultural stewardship.
Sources for this article include direct summary and analysis of the recent Quanta Magazine report (Quanta Magazine), current research overviews from Frontiers in Behavioral Neuroscience, Nature, and related public health guidance from the Alzheimer’s Association.