Why Humans Are Crazy for Crispy

Why Humans Are Crazy for Crispy
I’m always a bit wary of reductive thinking in popular discussions based on evolutionary biology, but this essay by anthropologist John S. Allen (from his forthcoming book, The Omnivorous Mind: Our Evolving Relationship With Food) raises some interesting issues about why we humans like noisy, crunchy, and crispy foods.

In The Babbo Cookbook, the celebrity chef and restaurateur Mario Batali wrote, "The single word 'crispy' sells more food than a barrage of adjectives. ... There is something innately appealing about crispy food." The hypothesis that crispy foods are innately appealing is a fascinating one. As an anthropologist interested in the evolution of cognition and the human diet, I think that maybe our attraction to crispy foods could give us insights into how people have evolved to think the food that they eat.

Perhaps one reason that crispy foods have such an appeal lies in their ability to stimulate our hearing as well as our senses of taste and smell. Crispiness in and of itself stands apart from other food qualities; this texture can be pleasurable even when combined with flavors that are themselves not necessarily all that appealing. Chewing crispy foods is louder than chewing noncrispy foods. If habituation [sensory neurons usually become less responsive with persistent exposure to a stimulus] takes longer given a stronger sensory signal, then we should enjoy eating crispy foods for a longer period of time during any given bout of eating. Of course, numerous factors are important in determining what we like to eat, but it is not unreasonable to suggest that we might like a particular crispy food in part because we like the way it sounds in our own heads.

Do we eat crunchy foods for longer periods than we eat quieter foods?

Simply reading, hearing, or saying the onomatopoeic terms "crispy" and "crunchy" is likely to evoke the sense of eating that type of food. Presumably this feeling would be represented in the brain by activation of the mouth and tongue regions of the primary motor cortex (and of course, when a word is actually said, the motor regions of the mouth are being directly activated). "Crispy" might be such a compelling descriptive term because, in a sense, hearing or saying it strongly promotes the motor imagery of eating—a food item with the word "crispy" attached to it is in some ways already being eaten by its potential consumer. "Crispy" in a menu could be quite persuasive, especially when coupled with the fact that crispy foods are often quite palatable for other reasons.

I feel the attraction of "crispy" food, but I don't know that it is more attractive than "soft" foods I enjoy such as chocolate mousse or even scrambled eggs. There's a lot more in the essay if you are intrigued.

I heard an NPR interview with the author (I believe it was on Science Friday) and I thought the whole thing was much ado about nothing.

Hmm... that's a really good question. Your basic flavor stuff is all based on nutritional needs: sweet, salty, sour, bitter and umami are all things you need (bitter as a deterrent to eating has been disproven, the vitamins and antioxidants in fruits are mainly bitter), and there's evidence that long-chain fats have their own receptors other than a generic "creamy" sensation.

But while crunchy is common in nature (a few fruits, a lot of vegetables), the more delicate but harder materials called crispy really don't. Only when you start processing foods do you approach crispy: well-done bacon and bread crust are probably the simplest, most others involve frying, I think.

JoelF wrote:Hmm... that's a really good question. Your basic flavor stuff is all based on nutritional needs: sweet, salty, sour, bitter and umami are all things you need (bitter as a deterrent to eating has been disproven, the vitamins and antioxidants in fruits are mainly bitter), and there's evidence that long-chain fats have their own receptors other than a generic "creamy" sensation.

But while crunchy is common in nature (a few fruits, a lot of vegetables), the more delicate but harder materials called crispy really don't. Only when you start processing foods do you approach crispy: well-done bacon and bread crust are probably the simplest, most others involve frying, I think.

The author reminds us insects are the original crispy food, followed by veggies. He speculates that their crispiness made these good nutritional sources attractive (as opposed to fruit that is sweet and juicy and perhaps more obviously inherently attractive). Of course, as he notes, cooking creates a whole bunch of delicious crispy foods.

Right, if I recall, his argument is basically: most crispy foods taste good. So there must be something genetic or evolutionary going on, or at least interesting.

The crunchy stale bread I bit into this morning is a counter example.

I read the essay, didn't hear the interview.

It seems as if many crispy foods are fried foods and fried foods are tasty (even if they are not good for us).