Essentials: How Smells Influence Our Hormones, Health & Behavior | Dr. Noam Sobel
Dr. Noam Sobel, a Weizmann Institute neurobiology professor and leading olfaction researcher, explores smell’s hidden influence on human life. They discuss body odor and friendship, fear-related chemosignals, baby odors and aggression, emotional tears, and how scents affect hormones and social behavior. Sobel also reveals efforts to digitize odors and develop electronic noses for medical diagnosis.
Top snips
Your Nose Is a Neural Gateway
1:03 – 4:32
Smell starts when airborne molecules travel 6–7 centimeters up the nose to the olfactory epithelium.
Inside are roughly 6–7 million receptors across about 350 types. Each odor creates a unique activation pattern, which reaches the olfactory bulb — then spreads to brain regions involved in memory, emotion, hormones, and behavior.
Humans have an utterly remarkable sense of smell.
— Noam Sobel
The Hidden Smell of a Handshake
5:40 – 8:26
Humans may not openly sniff strangers like dogs do — but we still sample one another chemically.
After shaking hands, people were significantly more likely to bring their hand to their nose and sniff it. They even smelled the opposite hand, suggesting the brain may compare self with other.
A handshake could be a subtle form of social information exchange.
Can Smell Predict Friendship?
10:03 – 13:59
People who instantly “click” may share more than interests or personality.
In one study, same-sex click friends had more similar body odors than random pairs. An electronic nose also predicted which strangers would view each other as friendly, nice, and likely to become friends.
Body odor may quietly influence the social chemistry behind connection.
Fear—and Even Aggression—Can Be Contagious
14:18 – 20:38
People in fear emit a body odor that others can detect without consciously identifying it. Exposure increases autonomic arousal — making fear somewhat contagious.
Another chemical, hexadecanal, produced opposite effects by sex:
- Reduced aggression in men
- Increased aggression in women
One theory: baby odors calm fathers while activating protective maternal aggression.
Tears Are a Chemical Blanket
21:51 – 25:26
Emotional tears may communicate more than sadness.
Although women’s tears were completely odorless to participants, sniffing them produced about a 14% drop in free testosterone within 20–30 minutes. Brain activity also decreased in the hypothalamus and fusiform gyrus.
Noam Sobel describes tears as a possible chemical blanket that helps protect against aggression.
The Future: Digitized Smell—and Medical Diagnosis
25:51 – 33:37
Noam Sobel’s lab developed an algorithm that predicts how similar two molecular mixtures will smell — even when they share zero molecules.
They created odor “metamers,” including a Chanel No. 5 alternative. In an early proof of concept, 15 of 16 people identified a digitally recreated violet scent.
Far ahead, electronic noses could detect disease through metabolic odors.