Neurogastronomy, neuroenology, neuroneuroscience – does it actually tell us anything?

I should think that we are all pretty well aware of the trend to neuroify pretty much everything (neuroaesthetics, neuroeconomics, uh neuroecology). In a review of Gordon Shepherd’s book Neuroenology: How the Brain Creates the Taste of Wine, Steven Shapin spends some time ruminating on whether there is any actual use to all of this.

First, some comments on the ‘neuroenology’:

The distinctions between olfaction and gustation, and even between orthonasal and retronasal olfaction, are only a start. There are many more scientific facts to be understood about, for example, how wine moves around in the buccal cavity and then on to the pharynx and esophagus; how these muscle- and gravity-induced movements contribute to sensory experience; how swallowing is controlled by the sCPG (the swallowing central pattern generator); how swallowed wine leaves behind in the mouth and pharynx both a sticky “matrix” and “volatiles” which can be released when post-swallow respiration resumes; how the first expiration of breath after swallowing has the highest concentration of volatiles, which some tasters call “the aroma burst” and which they consider “the strongest contributor to the taste of wine”; how the nerves of the tongue and nasal epithelium are arrayed and what paths they take to the brain; how and where the various sensory modes are integrated into the experience of flavor; and how some aroma molecules come to elicit olfactory responses…

But: does it actually change how we perceive wine? Can it be used to broaden or deepen our appreciation for wine (or food in general)?

So does any of this newly acquired “objective” knowledge about sensory modes bear at all on the nature and quality of subjective experience? Yes, it may, and no anti-reductionist humanist should feel obliged to deny that. Nevertheless, some claims for the aesthetic significance of scientific knowledge seem dubious. For example, Shepherd writes about the importance of the mucus membranes in the mouth, assuring us that “being aware of the structure of the mucus membranes, their various receptors, and the sensations they produce will enrich the wine-tasting experience.” But other neuroscientific stories seem more plausibly experience-changing. Scientists’ accounts of the retronasal pathway, for example, have the capacity to alter the attention paid to different types of olfactory experience. Our senses engage with a field of potential experience: we can attend to some features of that field and not to others, making some sensible aspects part of our focal awareness, and backgrounding or bracketing others. Having a “private” conversation in a public room, we focus on our partner’s talk and not on the booming, buzzing “background” sound washing over us. Then we overhear someone mentioning our name and we realize that the background noise has been waiting to be turned into signal through a change in attentiveness…

Michael Baxandall’s marvelous accounts of what he called “the period eye” in Quattrocento painting told us how late medieval people looked at paintings — the eye attending to the areas of azure and gold in the Virgin’s clothing, guided there because of the known preciousness and expense of these pigments, just as the Quattrocento period eye attended to certain shapes because of the widely distributed mercantile skill in gauging the internal volumes of barrels from their visible surfaces. Knowing this, you can look at paintings in this way too. The French sociologist Antoine Hennion — also a wine lover — has proposed a “sociology of attention” in which features of the sensory field are framed, parsed, and differently stressed, and in which subjects momentarily make themselves passive with respect to the sensed object. (“Ah, yes, now I notice that.”) So the framing impulses that can change or enhance sense experience need not derive from sensory science, and in these cases they do not, but sensory framing may come from scientific accounts of the structures and processes of sense perception. Neuroenology relates several stories that do have the capacity to change — to reframe, to reconstitute — our sensory experience. It’s an authentic debt that some pleasures might owe to some scientific accounts…

Then there are neuroscientific accounts of what areas of the brain “light up” in functional magnetic resonance imaging (fMRI) when laboratory animals sniff different volatile substances. Neuroscientists also tell us that when you — but not, in this case, laboratory animals — are told that one of two wines you’re drinking costs more, even when the wines are in fact the same, a different area of the cortex lights up for the “expensive” wine, and does so more brightly. Yet both of these findings bear as much relationship to the experience of aroma as knowing the location of the fuel pump does to the experience of driving a car: the pump and the brain area relating to odor have got to be somewhere, but knowing where they are doesn’t add to, subtract from, or change the experiences of driving or drinking.

Finally, a note on neuromania:

[T]he Italian psychologists Paolo Legrenzi and Carlo Umiltà have called “neuromania.” This is the tendency to go beyond identifying the neural bases for beliefs and sensations to the claim that beliefs and sensations really are their neural bases. The first claim is unexceptionable: of course, sensations are the result of interactions between our neural structures and things in the world and elsewhere in our bodies. In this sense, neuroscience has begotten a set of pleonasms — using more words than necessary to convey a specific meaning — and these pleonasms have metastasized through contemporary culture. Insofar as our mental life is neurally based — and who now doubts that? – neuro-whatever might just be a potentially useful way of reminding us of this fact: “neuroaesthetics” is aesthetics; “neuroethics” is ethics; “neuromarketing” is marketing; “neuroeconomics” is economics — even if traditional practitioners of aesthetics, ethics, and the like have not routinely had much to say about which areas of the brain “light up” when we see a beautiful painting, do a good deed, or buy a new car, and provided that we appreciate that what “goes on in the brain” includes what people know, remember, feel, and feel to be worth their attention.

 

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Humans are not the only copycats…

Both sets of newcomers seemed to follow social cues when selecting their snacks. Baby monkeys ate the same colour maize as their mothers. Seven of the ten males that migrated from one colour culture to another adopted the local colour preference the first time that they ate any maize. The trend was even stronger when they first fed with no higher-ranking monkey around, with nine of the ten males choosing the locally preferred variety. The only immigrant to buck this trend was a monkey who assumed the top rank in his new group as soon as he got there — and he may not have given a fig what anyone else ate.

 

“The take-home message is that social learning — learning from others rather than through individual trial and error — is a more potent force in shaping wild animals’ behaviour than has been recognized so far,” says Andrew Whiten, an evolutionary and developmental psychologist at St Andrews and co-author of the paper.

Humans are not the only copycats.  (More from Ed Yong).  With the key question being: what are the neural mechanisms that distinguish between social learning and ___ learning?

Soybeans all up in your brainz

It’s not exactly a secret that marijuana causes the munchies (see: Half Baked).  Marijuana aka cannabis contains what are called endocannabinoids (see the resemblance?), which are neuromodulators that your brain uses to regulate feeding.  But marijuana isn’t the only thing that contains endocannabinoids; vegetable oil does too:

If what happens in people mirrors what happens in animals, then the prevalence of soybean oil, corn oil and other polyunsaturated vegetable oils in today’s Western diet means your body is “dumping out a lot of these marijuana-like molecules into your brain,” explains Hibbeln, a nutritional neuroscientist. “You’re chronically a little bit stoned.”

Vegetable oil’s link to endocannabinoids is just one example of newfound and surprising ways that foods can confuse calorie-sensing networks and foster obesity — in some cases by damaging the brain. Especially troubling: Excess body weight itself can exaggerate the risk of the brain telling a well-fueled body that it is running on empty.

Deciding whether to eat or not eat seems like a pretty fundamental decision, no?  But decisions aren’t made in some platonic void, they’re contextual and dependent on our environment.  Hence, if your environment contains a lot of vegetable oils, well, you’re going to be making different decisions than if it didn’t.  What’s great about this research is that it explains how the neural pathway is modified by the environment, and which receptors are mediating this interaction with the environment.  But mostly, how the environment causes the munchies.

On the trail of genetic gastronomy

If I told you that our diets were shaped by our environments, would you be surprised?  If I said that what we ate was shaped by what we liked, would you be surprised by that either?  I should think the answer is no to both questions.  But still, thinking as a neuroscientist the question becomes: what is the neurological basis for why we like the food that we do?  Why do some people enjoy cilantro and some think that it tastes of soap?

It’s clear that our diet has shaped our evolution – just look at the relatively recent emergence of lactose tolerance in European populations.  It is a small leap to assume that the recipes we use may shape how we taste as well – and thus how we experience the world.  A news article in Nature explores the science of taste and recipes:

The Silk Road offers a potential paradise for such genetic exploration. The route traverses massive mountain ranges such as the Pamir and the Tian Shan in central Asia and passes through pockets of the nomadic tribes who originally populated the region, as well as ethnically diverse groups descended from traders who settled en route, often near the roadside inns called caravanserais. These populations did not tend to share their genes, but they did share recipes. Cuisines are remarkably similar along much of the Silk Road — variations on tandoor breads, noodles with vegetable or mutton sauces, and dried or fresh fruit. This means that differences in food preferences between groups are likely to be down to variations in genes rather than in dietary cultures, making them even more appealing to the geneticists…

The scientists have already identified eight variants in known genes, including one for an ion channel involved in sensing spicy-hotness, which are associated with a taste for particular foods. And they have found that variants of the gene for the TAS1R2 protein, part of a sweetness receptor, are associated with a strong liking for vodka and white wine…

There may be bigger scientific stories hiding in the data. Gasparini says that the team is seeing an emerging association in Tajikistani populations between an olfactory receptor gene and both sensitivity to bitter tastes and a tendency to mistake smells. If the finding holds up, it will be the first demonstrated genetic link between smell and taste perception, and it could help to explain how signals from different senses combine to sculpt individual food preferences.