The Thoughtful Animal

My contribution for the Guardian’s Science Blogging Festival has been posted!

Healthy, sane humans do not stab themselves in the thighs, or bathe their eyes in lemon juice. So why do we so love to assault one of the most sensitive organs in the human body, the tongue, with what amounts to chemical warfare? Chillies are unique among foods that we should otherwise not enjoy. For example, humans also have natural aversions to the bitterness of coffee or the harshness of tobacco, but those substances have some addictive qualities, which might make them desirable. Capsaicin, the compound that provides the mouth-watering punch of chillies, does not seem to have any addictive qualities whatsoever. And yet the preference for capsaicin is almost universal; nearly every culture has incorporated it into their cuisine in some way, for milllennia.

Head on over to check it out.

Comments

  1. #1 Jeremy Robson
    September 14, 2010

    The notion that consumption of chillis ’causes pain,’ and that therefore humans are masochistic in nature is a simple and compelling argument with one weakness. It is simply wrong. The ‘heat’ added to foods from which flavour is derived from other foods is pleasurable. Very few people who consume ‘hot’ foods would describe their experience as painful. There are curries which are purely ‘hot’ and without flavour. These are the bad ones, and there are flavoursome foods which are indeed very spicy, with the flavours originating from their other ingredients, such as onions, garlic, root ginger as well as fenugreek, cumin, coriander etc. Flavour combined with ‘heat’ is what makes certain foods compelling.

    Your argument is over simplified in extreme.

  2. #2 Jason G. Goldman
    September 14, 2010

    Jeremy: I think if you go over to The Guardian read the entire post (and not just the paragraph reproduced here), you will see a more nuanced argument.

  3. #3 Sharon Astyk
    September 14, 2010

    I’m afraid I have to agree with your other poster – the only quality of a chile pepper is not its heat – its flavor is integral to the experience. Moreover the sensory experience of chiles isn’t only painful.

    Sharon Astyk

  4. #4 Jason G. Goldman
    September 14, 2010

    Of course the heat isn’t all there is to such peppers. This is, though, an article *about* the heat.

  5. #5 Dunc
    September 14, 2010

    The strict binary conception of “pleasure” vs “pain” is far to simplistic, for starters. Then there’s the absurdity of the notion that anything children don’t immediately like is “aversive”. (Which wipes out most foods that aren’t heavily processed and loaded with sugar, and seems to be a uniquely American idea…) Sometimes good things need practice to appreciate.

  6. #6 Ahcuah
    September 14, 2010

    I had always assumed that the capsaicin was a decent de-wormer, thus our preference for it (and I can see how that could provide a genetic basis).

    But as I think about it, I realize I don’t really have any reason to think so. Have there been studies to show that the heat has an effect on things like hookworm, causing them to be excreted?

  7. #7 darwinsdog
    September 14, 2010

    Mammals perceive capsaicin as being “hot” but birds don’t. Mice would thoroughly chew and destroy a chili seed whereas birds swallow the seed and often eliminate it intact in their droppings. Hence, the metabolic synthesis of capsaicin in chilis is an adaptation that simultaneously inhibits mammalian seed predation while allowing seed dispersal by birds.

    As for why people can come to crave capsaicin despite it tasting “hot,” the just-so story I’ve always heard is that the perceived heat stimulates the secretion of endorphins in the brain. Capsaicin may taste hot but it does no tissue damage. People learn that no tissue damage ensues and come to like the stimulation of endorphin mediated pre-synaptic neurons. Perhaps this hypothesis is dated, I don’t know.

    I grow Mirasol chilis under drip irrigation in northern New Mexico, so-called because the pod grows upwards as if looking at the sun. They are a medium hot chili and are very flavorful. Slightly hotter than the highly overrated, imo, jalapeno, on average, but much tastier and more flavorful. I am quite literally addicted to them. One Mirasol pod provides 100% of the RDA for vitamins A & C.

  8. #8 Jason
    September 14, 2010

    I’m in with those confused by why it is supposed to be painful to eat spicy foods. It isn’t. Ok, the Scotch Bonnets or Bhut Jolokias in my garden tend to make me sweat a bit, but it is not “pain”. It just tastes interesting. If it actually hurt I wouldn’t eat them.

  9. #9 Paul W.
    September 14, 2010

    Jason,

    It’s not pain? Are you sure?

    My impression of my experience is that I’ve learned to feel pain and not mind, and kind of like it.

    I don’t usually think about it that way, but when eating very hot food (by U.S. but not Thai standards) I can stop and think about it, and I notice that my mouth is painfully burning. I just don’t mind that sensation anymore—the physical sensation of pain has gotten decoupled from the usual emotional response to it.

    I’d think this would be similar to the use of sedatives as though they were anaesthetics—if you give people enough valium, I think it is, they can endure a fair amount of pain, and just not care much. (Like consciously but Spockishly thinking Thats a lot of pain. Normally it’d bother me, but right now I just don’t care much. Fascinating.)

    I’m no expert on this, but I’d think there’s a connection there, and that people don’t normally distinguish between the perception of pain and the emotional response, but you can decouple them to some extent with drugs or appropriate experience.

    In particular, with eating hot peppers, you learn that you’re not really being damaged, and you stop minding what’s actually distinct pain.

    It makes sense to me, on this story, that other animals would have great difficulty with this—the connection between one and the other is fairly strong and reflexive, and it really helps to KNOW consciously with a fair degree of certainty that you’re not being damaged, and to believe it.

    Without that, it seems to me likely that the aversion is maintained even in animals that have a fair bit of experience eating hot food, because they’re always afraid when it happens. The link between the pain sensation and the emotional aversion may be strong enough that they freak out a bit every time, and that emotional freakout reinforces the aversion. (Rather like a panic disorder, and being afraid because you know that sort of situation IS unpleasant for you, even if it’s mainly fear of fear itself at root.)

    I wonder if you could desensitive animals to the aversiveness of hot food by giving them valium before the hot food, until they get used to feeling the pain and not minding, and then slowly withdrawing the valium.

  10. #10 Pierce R. Butler
    September 14, 2010

    Capsaicin… does not seem to have any addictive qualities whatsoever.

    You clearly haven’t been in my house when I’ve run out of Tabasco.

  11. #11 D. C. Sessions
    September 14, 2010

    Wow — the comments.

    It’s downright dangerous to even let people suspect that you might be disrespecting the noble pod, eh?

    (Writes dcs over a lunch consisting of, approximately, five roasted Hatch chiles, some onion, a bit of cheese, and an egg to hold it all together in a tortilla.)

    As for the perennial red/green argument: IMHO green for fresh, red for dried. Drop in on the Plaza Cafe in Santa Fe for their papas con chile and you can have them with both the red and green. IMHO the green is very good, but the red is awesome. Other dishes? Chile roja con carne sucks compared to chile verde.

    The there are my own mesquite smoked serranos. Can’t grow enough of the suckers to keep up with co-worker demand.

  12. #12 Jason G. Goldman
    September 14, 2010

    DCS: Yes, people are (apparently) very serious about their peppers! FSM forbid I suggest that spicy isn’t actually a taste but a pain response :-)

  13. #13 Eric Lund
    September 14, 2010

    And yet the preference for capsaicin is almost universal; nearly every culture has incorporated it into their cuisine in some way, for milllennia.

    The use of hot peppers in Asian cuisines only dates, IIRC to around 1700 when Dutch traders introduced peppers to the region. Even then, adoption was hardly universal. In China, you tend to find hot peppers in inland cuisines (especially Sichuan and Hunan), while the cuisines of the coastal plain (Mandarin and Cantonese) are much milder. The Japanese did not incorporate peppers in their cuisine to any great extent. Even in Europe, Hungary is an anomaly; peppers are much less prevalent especially among northern cuisines.

    I’ve heard a pop theory (nothing to back it up) to the effect that capsaicin helps to stimulate the appetite. This is more important in hot climates such as India or interior China than in cooler climates such as northern Europe. It also accounts for why tolerance for capsaicin is much lower here in New England than in the Southwest. I tend to request medium spice levels at my local Indian restaurant (I got burned, literally, by a South Indian vindaloo at a different restaurant many years ago), but I have noticed that most people who patronize that restaurant request mild spicing.

  14. #14 stripey_cat
    September 14, 2010

    I love chillis, but I would agree that it is a pain response. I think the thing, for me, is that the pain is fairly fleeting (apart from the time I sneezed over powdered cayenne and got it up my nose and into my eyes!), while the high from the pain response (as best as I can describe it) lasts for hours. After a while, you barely notice the pain (my tolerance for chilli is so much greater than DBf’s that he’ll be spitting stuff out at the stage I’m busily adding more!), but you still get the buzz. Also helped by the fact that many taste utterly delicious too!

  15. #15 Roland
    September 14, 2010

    @darwinsdog: “but birds don’t”. I beg to differ. I once put Tabasco on an oyster cracker and fed it to a seagull. Result: hilarious! I think peppers are popular in any culture whose food is otherwise bland: rice, tortillas, etc. get boring very quickly without a boost.

  16. #16 Dunc
    September 15, 2010

    In particular, with eating hot peppers, you learn that you’re not really being damaged, and you stop minding what’s actually distinct pain.

    It makes sense to me, on this story, that other animals would have great difficulty with this—the connection between one and the other is fairly strong and reflexive, and it really helps to KNOW consciously with a fair degree of certainty that you’re not being damaged, and to believe it.

    I take it you’ve never watched a badger raid a wasp’s nest? Many animals will happily put up with quite a remarkable amount of discomfort if there’s a decent food reward to be had.

  17. #17 darwinsdog
    September 15, 2010

    #15:

    @darwinsdog: “but birds don’t”. I beg to differ. I once put Tabasco on an oyster cracker and fed it to a seagull. Result: hilarious!

    When the pods are roasted the stems & seeds & charred skins go to the chickens. Capsaicin doesn’t taste hot to them or else these chickens are really into hot chili!

    “While mammals will avoid food containing as little as 100-1000 parts per million (ppm) of capsaicin, birds will readily consume up to at least 20,000 ppm (mind, we’re talking food that’s 2% pure capsaicin here). The difference seems to be that bird receptor cells are largely insensitive to capsaicin. Certain chemical modifications can make capsaicin somewhat aversive to birds, which shows that it is the structure of the molecule that is the key. Capsaicin sensitivity is perhaps the most well known difference between bird and mammalian receptors..”

    http://www.straightdope.com/columns/read/1857/are-birds-immune-to-hot-pepper-enabling-them-to-eat-vast-amounts-and-spread-the-seeds

  18. #18 Paul W.
    September 15, 2010

    Dunc:

    I take it you’ve never watched a badger raid a wasp’s nest? Many animals will happily put up with quite a remarkable amount of discomfort if there’s a decent food reward to be had.

    Well, no, I haven’t watched that, and I think my dog is rather more averse to that sort of thing than your badger. I have seen my dog clawing at his face after getting into food with ants in it, and (it seemed to me) being wary afterwards.

    I think this needs more careful scientific study to tease out the issues.

    Speaking of teasing out issues, isn’t somebody going to connect this up to discomfort thresholds during sexual arousal, sexual masochism, etc.

    Seriously, where is the sex talk? I’m really disappointed in you people.

  19. #19 Jason G. Goldman
    September 15, 2010

    Oh, Paul. Don’t you worry. It’s coming.

  20. #20 Paul W.
    September 15, 2010

    it’s coming

    There’s a surprise; I didn’t even hear it breathing heavy.

  21. #21 Jason G. Goldman
    September 15, 2010

    Jeez. This used to be a family establishment.

  22. #22 Paul W.
    September 15, 2010

    family establishment

    There you go.

  23. #23 Paul W., OM
    September 23, 2010

    So, um, where’s the post you promised in #19, connecting discomfort thresholds and, um, family establishment?

    I quiver with anticipation.

    (And how are we going to keep that discussion clean, anyhow?)

    BTW, in the context of people cognizing capsaicin pain as part of the “flavor” of food, I think it’s worth noting that multimodal sense perception isn’t that weird. (Humans are very good at what the robotics guys call “sensor fusion.”)

    For example, when you listen to loud music on a good stereo, you don’t usually notice it consciously, but you mostly don’t actually hear the very low bass with your ears—you feel the low frequency vibrations, in your chest (through the air) and feet and/or butt (through the floor and/or chair). Unless it’s very loud dance music or an intrusive movie sound effect, you’re not generally conscious of feeling the thumps, but it’s part of the listening experience. The auditory/tactile fusion is usually seamless.

    (That’s one reason why headphones can sound great, but give a less full and satisfying experience than cranking it up through speakers. Even fairly cheap headphones can reproduce sound more accurately than fairly expensive speakers, even ignoring problems of room acoustics, but it’s just not the same.)