I can eat pure sugar and pure fats and find it pleasurable thanks to the taste receptors; and salt to a lesser extent. But pure raw chilli products trigger irritation to the tongue, cheeks and nasal passages.
So it seems chillies do not "win over" taste receptors the way sugar, fat and salt do, but we do crave it.
What is the reward mechanism that makes spicy foods desirable?
Rozin (1996) provides an introduction to the psychology of food. Rozin and Schiller (1980) present a study on the acquisition of preferences for chili peppers.
In the abstract, they write:
Interviews, observations, and measurements were carried out in both Mexico and the United States. Exposure to gradually increasing levels of chili in food seems to be a sufficient condition for preference development. Chili likers are not insensitive to the irritation that it produces. They come to like the same burning sensation that deters animals and humans that dislike chili; there is a clear hedonic shift. This could be produced by association with positive events, including enhancement of the taste of bland foods, postingestional effects, or social rewards. It is also possible that the initial negative response to chili pepper is essential for the eventual liking. Chili stimulates an innate sensory "'warning" system but is not harmful. The enjoyment of the irritation may result from the user's appreciation that the sensation and the body's defensive reaction to it are harmless. Eating of chili, riding on roller coasters, taking very hot baths, and many other human activities can be considered instances of thrill seeking or enjoyment of "'constrained risks.
The paper also present research for and against desensitisation processes, although they note that this still requires some general rewarding quality to chilis.
Chili preference might be related to receptor desensitization. However, there would have to be positive features of chili that support a preference once the desensitization took place; otherwise, desensitization would lead to neutral responses. There is some reason to believe that desensitization to capsaicin could be a factor in human chili ingestion. High concentrations of capsaicin placed on the skin of humans or rats produce drops in sensitivity to subsequent applications of capsaicin that last for hours up to days after the initial treatment (Jancs6, 1960). Systemic injections of high levels of capsaicin into rats and guinea pigs produce months-long complete desensitization to the effects of capsaicin and other chemical irritants. Desensitized rats do not respond (as with paw wiping) to irritating solutions of capsaicin or ammonia placed in their eyes (Jancs6- Gfibor & Szolcs~myi, 1969)
I'm surprised simple endorphins havn't been mentioned, not even by those studies you cited Jeromy.
Without citing anything - I'm going to stick with this, which I used to do with my buddies before we'd go out, ha.
When you eat something super spicy (I'd just eat raw habaneros) and experience intense pain, you get an endorphin rush. Endorphins feel good. That's all.
If you think about it though it's a bit weird, because that's the same reason people purposefully cut themselves (the word for that pathology alludes me at the moment) and other things in that domain - except I'm (and I believe those who crave it - I never got to that level though) doing it by eating a spicy pepper.
"enhancement of the taste of bland foods, postingestional effects, or social rewards"
I can understand the enhancement of bland foods...yeah that's always good....and the social rewards from looking like a badass. However, spicy peppers don't seem to be too favorable for almost anyone "postingestionally" unless you want to experience pain.
I could see how if people really liked the taste of hot peppers/chilis they'd want to be desensitized to them too. Haha it's funny though that they become immune to ammonia in the eye. That sounds painful.
