Let’s say you lick a sheet of pure elemental copper. What makes it taste like copper? Is your tongue actually stripping copper atoms off the sheet and somehow analyzing them…?
Then, what if it’s an alloy, compound, or solution of some sort? Is your tongue individually analyzing each component and “summing” them up, or is the taste of a combined substance overall different from the sum of its individual parts?
Then what happens when you get into the actually complex things, like vegetables and meats and a hearty home-cooked meal made with all those things and sauces and carbs and such?
I know nothing about any of this, so please explain it like I’m five…
You have taste buds (which are small clusters of specialized receptor cells) on your tongue for five basic “true flavors”: salty, sweet, bitter, sour, and umami. Pretty much everything else is scent, which is why when you have a cold, foods can taste bland. When you chew, aroma compounds travel up the back of your throat to your nose. That’s “retronasal olfaction.”
The various dimensions of input have different pathways. The tastebuds go by way of cranial nerves to medulla to thalamus to gustatory cortex. Heat/cold (spicy hot/menthol) through a different cranial nerve. Olfactory information has a more direct route to the olfactory cortex. Those brain areas are then integrated at higher order cortical centers, send information to other brain areas, and receive information from each as well. All of which impacts the gestalt of what taste is experienced.
More information on the non-linear multimodal process than you likely want to know:
And it bears repeating: elementary school lied to you. There is no “zones” of the 5 different tastes mapped on your tongue. Certain types can cluster in an area, but they’re not elsewhere on the tongue too.
As said, your tongue detects which of the five basic tastes are in whatever you are tasting.
The scent component of taste is more complicated. As I understand it, the olfactory organs contain a large variety of different chemical sensors, and anything you scent (while tasting or otherwise) actives those sensors according to how sensitive that particular sensor is to it. Some are activated strongly, some weakly, some not at all. Your brain then interprets that pattern of activation as a scent.
Which is why wildly different things can share smells. They may be chemically different, but if they produce a close enough pattern of activation your brain will perceive it as the same scent.
Reality though is that the processing of taste perception is nowhere near as well studied as visual or even auditory processing.
Much is understood about the how visual cortical columns process information and the interplay between “bottom up” and “top down” processing - how the brain at multiple levels complete the perception filling in expected signal to make up for noise - sometimes falsely resulting in various perceptual illusions.
Taste perception? We don’t even know if it shares that columnar organization or not. How much top down occurs? (The literal bit of hunger being the best appetizer, of plating impact on flavor perception.) Are there taste perceptual illusions? (Yes BTW but not anywhere near as well studied as many other sensory illusions.)
Apologies for potentially overposting here, but the comparison above, contrasting to study of visual systems, got me thinking of studies on visual system development, such as the Hubel and Wiesel kitten experiments in which early monocular deprivation led to the undeprived eye taking over brain real estate from the deprived eye but not if either bother were equally deprived or it occurred outside of a sensitive period. It helped set up the understanding of brain development as portions that are innate (experience independent), some that is experience expectant (responding to normally universally available inputs), and experience dependent (refining based on environmental variability) - but more to the point of critical and sensitive periods of development. These processes are extensively studied for vision development but sparsely for taste.
Still there are inherited difference in taste bud receptors (which are actually broadly distributed other than on tongue - elsewhere in the gut, the endocrine system, and in the brain), innate taste preferences and aversions, and development that is experience dependent and expectant, with critical and sensitive periods including in utero and learned preferences from exposure to flavors that pass through in breast milk. With some fairly typical progressions through developmental progressions, including toddler and preschooler fear of new foods and textures (neophobia).
But understanding the actual mechanisms by which those developmental processes occur is fairly zilch. Even how much is changed value (reward and aversion systems) for different tastes vs actually changed perception of them? In the auditory system we literally can hear certain types of sounds more or less well as adults based on their importance in the language(s) we are exposed to in sensitive periods of language development (one recent example); does that occur for taste to any degree as well?
(@Reply sorry if this gets beyond explaining like you are five but it is interesting to me to realize how little we know about how taste works!)
Thank you for all the answers… really interesting. I didn’t know taste and smell are so interlinked. It’s like a evolutionary synesthesia.
And thank for you the interesting asides, @DSeid. I do wonder why there’s less research… seems like it would be a huge boon for the food industry. I mean, what more universal human experience is there than eating?
An emerging, non-food industry that studies this a lot is cannabis. The flavor and aroma of combustion materials was well studied by tobacco but cannabis is new and also made into a lot of novel products. Vaping canna or tobacco, for example, isn’t food and isn’t smoking, either, but there are manufacturing R&D and QC considerations for customer preferences.
And there is no doubt huge amounts of market research sort of studies. My sister in law’s sister had done some for a while - more smell related but close enough - the taste “illusions” bit is with that in mind. Lots done on what congeners contribute what to various alcoholic beverages. But research on how the brain develops in those systems and the physiology of them are different.
Two reasons I can think of right off.
First we care about vision and hearing, especially language development, lots and tend not to think about taste as being as critical of a sense.
Two it is a more challenging system to experimentally manipulate. Patching kitten eyes is relatively straightforward in comparison.
Well said and illusion is a good term. We do it all over the place. Take audio: we use file compression techniques and playback signal processing tricks to make little speakers sound good at low bitrates.
Or pixels or impressionist art. Hey, those blobs and dots sort of look like an image!
I suspect that one important reason is that humans are bad about communicating what they smell; that makes getting results from any experiments harder.
I posted this in a thread I had created about licorice in CS but it belongs here as well:
Plus the following, related to licorice but not quite, is interesting about why taste gets so hard to use as a model of brain sensory function:
At the heart of absinthe’s signature profile lies trans-anethole, a phenylpropene molecule responsible for the sweet, warm, slightly medicinal aroma and flavor associated with aniseed. Unlike ethanol or sugar, which activate broad receptor families, trans-anethole binds selectively—and potently—to specific olfactory receptors (OR7D4 in humans) and bitter taste receptors (TAS2R subtypes). Its volatility means it’s perceived both retronasally (as aroma released during chewing or sipping) and orthonasally (as scent before ingestion), amplifying its sensory impact.
Crucially, trans-anethole isn’t just “strong”—it’s perceptually complex. At low concentrations, it reads as sweet and herbal. At higher doses—like those found in undiluted absinthe—it activates bitter pathways more intensely, while also stimulating trigeminal nerve endings, producing a mild cooling or numbing sensation on the tongue and palate. This multisensory layering explains why some describe absinthe as “medicinal,” “soapy,” or “chemical”: it’s not one note, but a chord of aroma, taste, and tactile feedback.
Yet concentration alone doesn’t explain the divide. Two people drinking the same glass of properly diluted absinthe—say, 3–5 parts water to 1 part spirit—can have diametrically opposed reactions. One finds it refreshing and layered; the other gags or pushes the glass away. That variance points squarely to biology—not brewing technique or serving ritual.
The Genetics of Flavor Aversion: OR7D4 and the “Licorice Gene”
In 2012, a landmark study published in Nature Neuroscience identified a genetic variant in the olfactory receptor gene OR7D4 that directly correlates with perception of trans-anethole. Researchers discovered that individuals carrying two copies of the RT allele (rs6591536) perceive trans-anethole as intensely sweet and pleasant—often describing it as “anise,” “fennel,” or “candy-like.” Those with two copies of the WM allele, however, report it as overwhelmingly unpleasant—“urinous,” “sweaty,” or “rotten.” Heterozygotes (one of each) fall somewhere in between, often neutral or mildly negative.
This isn’t theoretical. The RT/WM polymorphism affects roughly 15–20% of Europeans, 30–40% of East Asians, and up to 55% of West Africans—distribution patterns that align closely with historical culinary use of aniseed and related spices. In populations where anise was traditionally used medicinally or culinarily (e.g., Mediterranean and Middle Eastern cuisines), the RT allele appears to have undergone positive selection—likely because detecting sweetness in plant compounds signaled safe, energy-rich food sources. Conversely, the WM variant may have conferred advantage in avoiding potentially toxic aromatic plants.
(Not quite related to licorice because while trans-anethole is often perceived as “licorice” actual licorice root has little to no trans-anethole in it, illustrating @Der_Trihs ’s point specific to olfaction about taste - different paths to similar perceptions.)
But yeah hard to have even a good shared vocabulary about tastes and smells when we may not be sharing the perceptual experiences?