To Smell Is to Remember: The Psychology of Scent in the Age of AI

Among the five senses, olfaction is often regarded as the most elusive — less examined, less discussed, and frequently underestimated. Yet it is also the most intimately tied to memory, emotion, and identity. Unlike vision or hearing, the sense of smell bypasses the brain’s analytical pathways and connects directly to its emotional and memory centers.

A fleeting scent can evoke vivid recollections long thought forgotten, triggering emotional responses more immediate than those elicited by images or words. This unique neurobiological pathway positions olfaction as not merely a sensory input, but a powerful psychological and cognitive mechanism.

In parallel, artificial intelligence has made remarkable strides in simulating human sensory perception — from visual recognition to speech processing. Yet the domain of artificial olfaction remains nascent, raising critical questions: Can a machine truly replicate the emotional and mnemonic depth of scent? What does it mean for AI to ‘smell’?

Few senses are as intimately tied to emotion and memory as smell — and none pose a greater challenge to artificial replication.

The Emotional Architecture of Smell

Olfaction occupies a uniquely intimate position among the human senses — not only in its biological structure, but in its privileged access to the emotional and mnemonic core of the brain. Unlike visual or auditory stimuli, which pass through the thalamus before reaching conscious awareness, olfactory signals follow a more direct and ancient route. This deviation is not incidental, but fundamental to how smell is experienced, processed, and remembered.

When odor molecules bind to receptors in the nasal epithelium, signals are transmitted to the olfactory bulb, situated just above the nasal cavity. From there, rather than being filtered through higher-order cognitive processing, these signals are relayed directly to the amygdala and hippocampus — the brain's primary centers for emotion and memory, respectively. This neural architecture allows smell to bypass conscious mediation and reach the most emotionally reactive and autobiographical parts of the mind.

This is the neurological basis of what is commonly known as the “Proustian effect” — the phenomenon by which a scent can instantaneously evoke vivid, emotionally loaded memories, often from early life. The French novelist Marcel Proust famously described this in In Search of Lost Time, where the smell of a madeleine dipped in tea unexpectedly transported him into the rich landscape of his childhood.

Scientific research supports this literary observation. In a widely cited study, Herz and Schooler (2002) found that odor-evoked memories are not only more emotional, but also more vivid and older than memories triggered by visual or verbal cues. These findings suggest that olfaction does not merely assist memory; it actively accesses and shapes autobiographical narrative at a level that other senses cannot reach.

Evolutionarily, this makes sense. As one of the most primitive senses, smell played a crucial role in survival — helping early humans detect food, avoid toxins, recognize kin, and sense danger through pheromonal cues. Although modern life has distanced us from this instinctual dependency, the underlying architecture remains intact. Smell continues to operate beneath the threshold of conscious attention, shaping our perceptions, moods, and interpersonal connections in subtle but profound ways.

Recent studies have extended this understanding to clinical and social domains. In neurology, olfactory dysfunction is now considered an early biomarker for neurodegenerative diseases such as Alzheimer’s and Parkinson’s, often preceding cognitive symptoms by years. In social psychology, experiments have shown that human body odor carries emotional information, conveying signals of fear, stress, or even attraction — processed subconsciously by others.

In short, olfaction is not a lesser sense, but a deep structure of emotional and cognitive life. Its neural shortcuts allow it to bypass logic, language, and even awareness — reaching us in the rawest and most human ways.

Artificial Olfaction: Can Machines Learn to Smell?

In recent years, artificial intelligence has made astonishing progress in mimicking human sensory capabilities. Machines can now recognize faces with greater precision than the human eye, and generate speech that is nearly indistinguishable from human voices. But among the five human senses, smell remains the most elusive and least developed in the realm of artificial simulation.

Unlike vision or hearing, olfaction is inherently complex, both in its chemical variability and in its psychological interpretation. For humans, to smell is not only to detect molecules, but to access memory, emotion, and subjective meaning. This depth poses a fundamental challenge for computational modeling — a challenge that lies not only in chemistry, but in consciousness.

Yet the field of artificial olfaction, often referred to as the development of electronic noses (e-noses), is gaining momentum. These systems combine chemical sensor arrays with machine learning algorithms to detect and classify volatile compounds. In medical applications, for instance, e-noses have been used to identify diseases such as lung cancer or diabetes through breath analysis. In the food industry, they assist in quality control by detecting spoilage or contamination. Their pattern-recognition capabilities are fast and efficient — even superior to human noses in certain tasks.

Advancements in deep learning and neural networks have further accelerated this field. Notably, a 2021 study by Google Research introduced a model trained to predict human-perceived scent qualities based solely on molecular structure. Using graph neural networks, the AI was able to label molecules with descriptors such as “floral,” “fruity,” “musty,” or “spicy,” demonstrating the potential of algorithmic learning to emulate human olfactory classification.

However, these systems remain limited in scope. What they excel at is detection — identifying the presence of chemical signatures and mapping them to predefined categories. What they lack is interpretation in a human, psychological sense. An e-nose can detect jasmine, but it cannot associate it with the scent of someone’s mother, a summer evening, or a feeling of longing. These associations are not embedded in molecules themselves, but in the lived experiences and emotional histories of individuals — elements machines do not possess.

More fundamentally, AI lacks the biological architecture that makes smell so powerful in the human mind. It has no hippocampus to link scent to spatial memory, no amygdala to encode emotional salience, no embodied history to tie the two together. Even the most sophisticated algorithms are, at their core, statistical engines — capable of impressive inference, but devoid of subjective awareness.

This reveals a deeper boundary between human and machine perception: while machines are advancing in sensing, they remain limited in feeling. And nowhere is this gap more visible than in the domain of olfaction. Scent resists abstraction. It is embodied, emotional, and often unconscious — qualities that challenge not only engineers, but philosophers and psychologists alike.

Nonetheless, artificial olfaction continues to evolve. Its potential in diagnostics, environmental monitoring, food safety, and even restorative therapies for anosmia — smell loss — is undeniable. As this field progresses, it forces us to reconsider not only how machines can replicate human senses, but what it truly means to sense something.

The Limits of Sensing Without Feeling

The replication of human perception has long been a central ambition in artificial intelligence. Machines can now see, hear, and even "speak" with remarkable fluency. But what separates perception from experience — and simulation from understanding — becomes most evident when we consider the sense of smell.

Olfaction is uniquely embedded in the human emotional apparatus. It is not only a tool for detection but a gateway into memory, mood, identity, and instinct. A scent may evoke longing, comfort, or even grief — not because of its molecular structure, but because of the personal history and emotional associations it carries. These dimensions of meaning are not inherent in the stimulus, but in the subjective framework of the perceiver.

Artificial systems, no matter how advanced, do not possess such frameworks. They do not feel. They do not remember. A neural network may associate a molecular structure with the label “smoky,” but it does not experience that smokiness as the echo of a fireplace in childhood or the residue of absence in a long-empty room. These associations arise not from the data, but from the conscious self — from a continuity of memory, emotion, and embodied experience that machines fundamentally lack.

This limitation is not merely technical; it is existential. To smell, in the human sense, is to connect the present moment to a personal and emotional past. It is a convergence of perception and narrative. Machines can recognize patterns, but they do not possess stories. They can categorize odors, but they do not feel nostalgia.

The case of olfaction illustrates a broader truth: intelligence, however powerful, is not the same as consciousness. The ability to process sensory input does not entail the capacity to assign personal or emotional significance. In this way, artificial olfaction reveals the limits not only of current technology, but of any system divorced from the mechanisms of emotion and memory.

As AI systems grow more integrated into human life, understanding these limits becomes increasingly important. The line between simulation and empathy, between recognition and resonance, may define the ethical and emotional boundaries of future human–machine interaction.

Smell, in its quiet immediacy, reminds us that to sense is not always to understand — and that understanding often begins with feeling.

Olfaction as a Psychological Portal

In psychology, olfaction is increasingly recognized not only as a sensory function but as a gateway into the structure of experience itself. Among the senses, smell is uniquely nonverbal, emotionally potent, and intimately linked to memory and identity. These qualities make it a profound subject of psychological inquiry — one that reveals how perception and personality are interwoven.

Unlike visual or auditory stimuli, olfactory input is rarely described with precision. People often say “it smells like something I can’t describe,” because the language for scent is limited, and because scent memory is often episodic and emotional, rather than conceptual. This mismatch between perception and language reflects how olfaction bypasses cognitive processing and engages what psychologists refer to as affective memory.

Smell also plays a significant role in the formation of autobiographical memory. It not only triggers past events but often reconstructs emotional states associated with those memories. A single scent can revive not just a place or a time, but a version of the self that existed in that moment — what some psychologists describe as the “remembered self.”

Moreover, scent has powerful effects on mood, behavior, and interpersonal perception. Research has shown that certain smells can unconsciously elevate or suppress mood, influence social trust, and even affect perceived attractiveness. In developmental psychology, infants rely on maternal scent for attachment and emotional regulation. In social psychology, body odor conveys emotional information such as fear or anxiety, often without conscious awareness.

At a deeper level, scent may also contribute to the sense of continuity in the self. Because olfactory memories are often tied to specific life periods and intimate spaces, they help structure an internal narrative — a lived story that anchors personal identity. When people lose their sense of smell (a condition known as anosmia), they often report not only diminished pleasure, but also a weakened sense of connection to others and to themselves.

This convergence of perception, emotion, and identity through smell is what makes olfaction such a psychologically rich domain. It resists abstraction and analysis, yet it shapes the deepest contours of subjectivity. In this way, olfaction serves as a reminder that psychological life is not built only on thought, but on embodied, affective experience — and that the self is as much a felt phenomenon as it is a cognitive one.

Smell, Memory, and the Meaning of Experience

If a machine learns to smell, will it ever learn what a scent means to a person?

Smell is often referred to as the most primitive of the senses — and yet, in many ways, it is also the most profound. It bypasses thought and goes straight to feeling, skipping language to speak directly to memory, emotion, and identity. It is not only a sense that detects the world, but one that anchors us to ourselves, shaping the emotional continuity of our lives.

In psychological terms, olfaction functions as a bridge between past and present, sensation and self. A scent can awaken a version of ourselves we had long forgotten, or cast our present mood into sharp emotional relief. Its influence is subtle, often invisible, yet deeply formative. As we have seen, smell weaves through memory, mood, attachment, and even the social fabric of human interaction — a silent architect of psychological life.

In contrast, artificial systems — no matter how sophisticated — can detect patterns, but they do not remember. They can label scents, but they do not long for them. This distinction reveals a fundamental boundary between intelligence and experience, between simulation and being. What makes smell so psychologically powerful is not just its biological design, but the meaning it acquires through time, emotion, and memory.

As technology continues to evolve, we may build machines that match or even surpass human sensory accuracy. But replicating the emotional architecture of perception remains a deeper challenge — one that reaches beyond data, beyond pattern recognition, and into the nature of what it means to feel, to remember, and to be.

Smell reminds us that not all understanding is rational, and not all experience is visible. Some truths arrive through the nose — unannounced, unprocessed, and unforgettable.