Essentials: How Smell, Taste & Pheromones Shape Behavior
This Huberman Lab Essentials episode explores how smell, taste, and chemical sensing influence memory, alertness, and interpersonal communication. Dr. Andrew Huberman discusses the neurobiology of these senses and provides practical tools to enhance learning, sensory function, and brain health.
Deep Dive Analysis
11 Topic Outline
Introduction to Chemical Sensing: Smell, Taste, and Human Communication
Human Biological and Hormonal Responses to Other People's Tears
Neurobiology of Smell: Innate, Learned, and Accessory Pathways
Pheromonal Effects in Animals: Vandenberg and Coolidge Effects
Sniffing and Nasal Breathing for Enhanced Alertness and Learning
Olfactory Neuron Replenishment and Brain Health Connection
Olfactory Dysfunction as a Readout for Traumatic Brain Injury Recovery
Specific Odors Like Peppermint for Increasing Alertness
Five (and Potentially Six) Taste Modalities and Their Functions
The Tongue and Mouth as a Chemical Sensing Apparatus
Human Subconscious Chemical Signaling and Interpersonal Evaluation
7 Key Concepts
Olfactory Bulb
A collection of neurons located at the base of the brain, which extend processes into the mucosal lining of the nose to detect odorant compounds. These neurons send signals deeper into the brain via pathways for innate, learned, and accessory olfactory responses.
Accessory Olfactory Pathway
A neural pathway that, in animals, is responsible for true pheromone effects, influencing reproductive biology and social behaviors. Its existence and function as a separate system in humans are controversial.
Vandenberg Effect
A pheromonal effect observed in some animal species where exposure of a pre-pubertal female to the scent or urine of a sexually competent male triggers an earlier onset of puberty and ovulation.
Coolidge Effect
A pheromonal effect where a male or female animal, having mated to exhaustion with one partner, spontaneously regains the desire and ability to mate when a new partner (or just their odor) is introduced.
Gustatory Nerve
A collection of nerve bundles originating from the tongue that transmits taste information to specific brain regions, including the nucleus of the solitary tract, thalamus, and insular cortex, where different tastes are processed and perceived.
Umami
One of the five (or potentially six) basic taste modalities, detected by specific receptors on the tongue. It signals the presence of amino acids, which are vital for the body's function.
Cribriform Plate
A Swiss cheese-like bone plate in the skull through which olfactory neurons extend into the nose. This structure is vulnerable to damage during head injuries, leading to the shearing of these neurons and subsequent olfactory dysfunction.
8 Questions Answered
Human tears, particularly those evoked by sadness, contain chemicals that can significantly reduce testosterone levels and decrease activity in brain areas associated with sexual arousal in men who smell them.
Volatile chemicals are inhaled into the nose, trapped by a mucosal lining, and detected by neurons extending from the olfactory bulb. These neurons send signals to the brain via pathways for innate responses (e.g., smoke), learned associations (e.g., specific memories), and potentially accessory olfactory functions.
Yes, the act of inhaling (sniffing) itself increases alertness in the brain, improving attention, focus, and the ability to learn and remember information, independent of what is being smelled. Nasal breathing specifically has been shown to enhance learning compared to mouth breathing.
The ability to smell and taste well is a strong indicator of brain health because olfactory neurons are unique in their ability to be continually replenished throughout life. Enhancing smell can promote neurogenesis in these neurons.
Olfactory dysfunction is common after TBI because the cribriform plate, through which olfactory neurons extend, can shear these wires during head impacts. The recovery of one's sense of smell can serve as a partial gauge for recovery from a head injury.
There are five established taste modalities: sweet (signals energy/sugars), salty (signals electrolytes), bitter (signals poisons, triggers gag reflex), umami (signals amino acids), and sour (signals spoiled/fermented food, triggers pucker response). A sixth, fat, is also being investigated.
Scents like peppermint and ammonia (found in smelling salts) can increase attention and create an arousal response by triggering specific olfactory neurons that communicate with brain centers like the amygdala, which are involved in alertness.
While true pheromonal effects in humans are debated, there is clear evidence of chemical signaling between humans, such as the effect of tears on male hormones and subconscious chemical evaluations during social interactions.
9 Actionable Insights
1. Nasal Breathing for Focus & Learning
Focus on nasal breathing during any focused work that doesn’t require speaking or eating, as inhaling through the nose increases alertness, attention, focus, and memory, improving learning outcomes.
2. Eliminate PFAS from Cookware
Actively choose and use cookware that is completely PFAS and toxin-free, such as Our Place products, to avoid toxic compounds linked to hormone disruption, gut microbiome issues, and fertility problems.
3. Daily Electrolyte Intake
Dissolve one packet of Element in 16-32 ounces of water and drink it first thing in the morning, and consume another packet during physical exercise, especially on hot days, to ensure proper hydration and adequate electrolyte balance.
4. Train & Enhance Smell
Actively interact with a variety of odors, preferably positive ones, and practice sniffing more to train and enhance your sense of smell, as this system is highly amenable to rapid behavioral training and helps keep it ’tuned up'.
5. Olfactory Training Post-Injury
If recovering from a head injury, engage in olfactory training by closely interacting with odors and focusing on inhaling more to enhance your sense of smell, which can stimulate new neuron growth and indicate sensory performance recovery.
6. Heighten Smell & Taste Perception
To enhance perception, take an object like an orange, smell it, perform 10-15 inhales through the nose, and then smell it again to significantly increase the richness of your experience of that smell and taste.
7. Boost Alertness with Peppermint
Sniff peppermint or other minty scents to increase attention and create an arousal response, which can help wake up your system and improve focus, though less intensely than ammonia salts.
8. Recognize Subconscious Chemical Cues
Be aware that humans subconsciously sense and evaluate chemicals from others (e.g., through breath or skin contact like handshakes followed by touching eyes), and observe these behaviors in your environment to understand interpersonal chemical communication.
9. Caution: Avoid Direct Ammonia Sniffing
Do not sniff real ammonia directly or too closely, as it is a toxic scent that can damage your olfactory epithelium and vision; if using smelling salts, understand proper usage to avoid severe damage to your olfactory pathway.
7 Key Quotes
The act of inhaling itself wakes up the brain. It's not about what you're perceiving or what you're smelling and indeed sniffing as an action, inhaling as an action has a powerful effect on your ability to be alert, your ability to attend, to focus, and your ability to remember information.
Andrew Huberman
How well we can smell and taste things is actually a very strong indication of our brain health.
Andrew Huberman
It is a total myth, complete fiction, that different parts of your tongue harbor different taste receptors.
Andrew Huberman
Olfaction, smell, is the most ancient sense that we have.
Andrew Huberman
The taste system, just like the olfactory system and the visual system, was laid down for the purpose of moving towards things that are good for us and moving away from things that are bad for us.
Andrew Huberman
People are shaping each other's biology all the time by way of these chemicals that are being traded from one body to the next through air and skin-to-skin contact and tears.
Andrew Huberman
There are things floating around in the environment, which we call volatile chemicals. So when you actually smell something, like let's say you smell a wonderfully smelling rose or cake, yes, you are inhaling the particles into your nose. There are literally little particles of those chemicals are going up into your nose and being detected by your brain.
Andrew Huberman
2 Protocols
Enhance Sense of Smell and Sniffing Ability
Andrew Huberman- Take an item with a distinct odor (e.g., an orange).
- Perform 10-15 inhales and exhales through the nose while smelling the item.
- Smell the item again to notice a significant increase in the richness of your perception of that smell.
Olfactory Training for Brain Health and TBI Recovery
Andrew Huberman- Actively interact with a variety of different odors, preferably positive ones.
- Focus on inhaling more and sniffing closely to discern the nuances of those smells, which helps create new olfactory neurons and enhance abilities.