Retronasal Olfaction

mechanism

Much of flavor is smell arriving from food in or near the mouth. Reduce that olfactory input and foods can become difficult to distinguish even though the tongue still receives their chemicals.

Pinch your nose and cinnamon, cumin, and paprika—ingredients that seem unmistakably different—can become surprisingly hard to tell apart. The tongue has not stopped working; a major part of what you called “taste” has disappeared.

Flavor takes the back route

The episode’s estimate is startling: 80–90% of taste is actually smell. Food in or near the mouth supplies olfactory information, and the brain combines it with the tongue’s chemical input into a single experience called flavor. Block the smell component and that construction loses much of its detail.

Retronasal olfaction is therefore one moving part in crossmodal flavor perception, not evidence that the tongue contributes nothing. It also explains why temperature can change an eating experience when it changes the aroma reaching the nose.

Where it shows up

Three spices, one blurred signal

The plugged-nose comparison collapses the apparent distance between cinnamon, cumin, and paprika. Their familiar identities depend heavily on olfactory cues; remove those cues and the remaining chemical input is less discriminating. What feels like a simple taste judgment is partly a sensory assembly—and distinct from learned differentiation through perceptual-narrowing.

Smell is dominant, not solitary

This mechanism does not make every flavor difference an olfactory illusion. The experiment says that reducing smell makes these spices hard to distinguish, not that the tongue receives no information. Retronasal olfaction explains a large missing component; the wider experience still belongs to crossmodal-perception.

Separate the channels

Tomorrow, compare tiny samples of cinnamon, cumin, and paprika twice: first while pinching your nose, then immediately after releasing it. Notice which distinctions return with smell. That contrast gives you a cleaner diagnosis than treating every food preference—or every acquired taste—as a verdict delivered by the tongue alone.

Episodes that teach this

We Eat With Our Eyes - How Your Taste Buds Are Tricked - FutureIQ 3,044 views
The speaker says '80 90% of taste is actually smell' and explains that plugged-nose experiments make cinnamon, cumin, and paprika hard to distinguish.