Sensing Smells
Smell, or olfaction, detects chemicals floating in the air. Receptors high inside the nose identify odor molecules, and the brain recognizes the pattern as a particular smell.
Questions you may have include:
- How does smell work?
- Why is smell tied to memory?
- What are its quirks?
How smell works
As you breathe, airborne molecules reach a patch of olfactory receptors high in the nasal cavity. These receptors respond to different molecules and send signals to the olfactory bulb in the brain, which the brain interprets as specific odors. Humans can distinguish an enormous number of different smells.
Smell, memory, and emotion
The smell pathways connect closely to brain areas involved in memory and emotion, which is why a particular scent can suddenly bring back a vivid memory or feeling more powerfully than other senses do.
A quirk of smell
Smell also fatigues: when you are exposed to a constant odor, you soon stop noticing it, as the sense adapts and frees attention for new or changing smells. Smell also combines with taste to create the experience of flavor.
Summary
Smell works as olfactory receptors in the nose detect airborne molecules and signal the brain, which recognizes specific odors. Its close link to memory and emotion gives scents their power to evoke the past, it adapts to constant smells, and it combines with taste to produce flavor.