Can science account for taste?

I was asked the question “From a scientific point of view, how are our tastes created?” Here’s my answer.

“There’s no accounting for taste!”

Typically we explain taste — in food, music, movies, art —  in terms of culture, upbringing, and sheer chance. In recent years there have been several attempts to explain taste from biological perspectives: either neuroscience or evolutionary psychology. In my opinion these types of explanations are vague enough to always sound true, but they rarely contain enough detail to account for the specific tastes of individuals or groups. Still, there’s much food for thought in these scientific proto-theories of taste and aesthetics.

[An early aesthete?]

Let’s look at the evolutionary approach first. An evolutionary explanation of taste assumes that human preferences arise from natural selection. We like salt and sugar and fat, according to this logic, because it was beneficial for our ancestors to seek out foods with these tastes. We like landscape scenes involving greenery and water bodies because such landscapes were promising environments for our wandering ancestors. This line of thinking is true as far as it goes, but it doesn’t go that far. After all, there are plenty of people who don’t much care for deep-fried salty-sweet foods. And many people who take art seriously quickly tire of clichéd landscape paintings.

[Are you a homo sapien? They you must love this. 😉 ]

Evolutionary psychology can provide broad explanations for why humans as a species tend to like certain things more than others, but it really provides us with no map for navigating differences in taste between individuals and groups. (These obvious, glaring limitations of evolutionary psychology have not prevented the emergence of a cottage industry of pop science books that explain everything humans do as consequences of the incidents and accidents that befell our progenitor apes on the savannahs of Africa.)

Explanations involving the neural and cognitive sciences get closer to what we are really after — an explanation of differences in taste — but not by much. Neuroscientific explanations are essentially half way between cultural theories and evolutionary theories. We like things because the ‘pleasure centers’ in our brains ‘light up’ when we encounter them. And the pleasure centers are shaped by experience (on the time scale of a person’s life), and by natural selection (on the time scale of the species). Whatever we inherit because of natural selection is presumably common to all humans, so differences in taste must be traced to differences in experience, which become manifest in the brain as differences in neural connectivity and activity. If your parents played the Beatles for you as a child, and conveyed their pleasure to you, then associative learning might cause the synapses in your brain that link sound patterns with emotional reactions to be gradually modified, so that playing ‘Hey Jude’ now triggers a cascade of neural events that generate the subjective feeling of enjoyment.

[What’s not to love about the Beatles?]

But there is so much more to the story of enjoyment. Not everyone likes their parents’ music. In English-speaking countries there is a decades-old stereotype of the teenager who seeks out music to piss off his or her parents. And many of us have a friend who insists on listening to music that no one else seems to have heard of. What is the neural basis of this fascinating phenomenon?

We must now enter extremely speculative territory. One of the most thought-provoking ‘theories’ of aesthetics that I have come across was proposed by a machine learning researcher named Jürgen Schmidhuber. He has a provocative way of summing up his theory: Interestingness is the first derivative of beauty.

What he means is that we are not simply drawn to things that are beautiful or pleasurable. We are also drawn to things that are interesting: things that somehow intrigue us and capture our attention. These things, according to Schmidhuber, entice us with the possibility of enhancing our categories of experience. In his framework, humans and animals are constantly seeking to understand the environment, and in order to do this, they must be drawn to the edge of what they already know. Experiences that are already fully understood offer no opportunity for new learning.  Experiences that are completely beyond comprehension are similarly useless. But experiences that are in the sweet spot of interestingness are not boringly familiar — but they are not bafflingly alien either. By seeking out experiences in this ‘border territory’, we expand our horizons, gaining a new understanding of the world.

For example, I’m a Beatles fan, but I don’t listen to the Beatles that often. I am, however, intrigued by music that is ‘Beatlesque’: such music can lead me in new directions, and also reflect back on the Beatles, giving me a deeper appreciation of their music.

The basic intuition of this theory is well-supported by research in animals and humans. Animals all have some baseline level of curiosity. Lab rats will thoroughly investigate a new object introduced into their cages. Novelty seems to have a gravitational pull for organisms.

But again, there are differences even in this tendency. Some people are perfectly content to eat the same foods over and over again, or listen to the same songs or artists. At the other extreme we find the freaks, the hipsters, the critics, the obsessives, and all the assorted avant garde seekers of “the Shock of the New”.

Linking back to evolutionary speculation, all we can really say is that even the desire for novelty is a variable trait in human populations. (Actually it’s multiple traits: I am far more adventurous when it comes to music than food.) Perhaps a healthy society needs its ‘conservatives’ and its ‘progressives’ in the domain of taste and aesthetic experience. Group selection  — natural selection operating on tribes, societies and cultures — is still somewhat controversial in mainstream evolutionary biology, so to go any further in our theories of taste we have to be willing to wander on the wild fringes of scientific thought…

… those fringes are, after all, where everything interesting happens! 🙂

For more speculation on interestingness, beauty, and the pull of the not-completely-familiar, see this essay I wrote. I go into more detail about Schmidhuber’s theory about interestingness:
From Cell Membranes to Computational Aesthetics: On the Importance of Boundaries in Life and Art

This has nothing to do with science, but I find this David Mitchell video on taste very funny:

After writing this answer I realized that the questioner was most probably asking about gustation — meaning, the sense of taste. Oh well.

Why can most people identify a color without a reference but not a musical note?

[I was asked this on Quora. Here’s a slightly modified version of my answer.]

This is an excellent question! I’m pretty sure there is not yet a definitive answer, but I suspect that the eventual answer will involve two factors:

  1. The visual system in humans is much more highly developed than the auditory system.
  2. Human cultures typically teach color words to all children, but formal musical training — complete with named notes — is relatively rare.

When you look at the brain’s cortical regions, you realize that the primary visual cortex has the most well-defined laminar structure in the whole brain. Primary auditory cortex is less structured. We still don’t know exactly how the brain’s layers contribute to sensory processing, but some theories suggest that the more well-defined cortices are capable of making more fine distinctions.

[See this blog post for more on cortical lamination:
How to navigate on Planet Brain]

However, I don’t think the explanation for the difference between music and color perception is purely neuroscientific. Culture may well play an important role. I think that with training, absolute pitch — the ability to identify the exact note rather than the interval between notes — could become more common. Speakers of tonal languages like Mandarin or Cantonese are more likely to have absolute pitch, especially if they’ve had early musical training. (More on this below.)

Also: when people with no musical training are exposed to tunes they are familiar with, many of them can tell if the absolute pitch is correct or not [1] Similarly, when asked to produce a familiar tune, many people can hit the right pitch. [2]. This suggests that at least some humans have the latent ability to use and/or recognize absolute pitch.

Perhaps with early training, note names will become as common as color words.

This article by a UCSD psychologist described the mystery quite well:

Diana Deutsch – Absolute Pitch.

As someone with absolute pitch, it has always seemed puzzling to me that  this ability should be so rare. When we name a color, for example as  green, we do not do this by viewing a different color, determining its  name, and comparing the relationship between the two colors. Instead,  the labeling process is direct and immediate.

She has some fascinating data on music training among tonal language speakers:

” Figure 2. Percentages of subjects who obtained a score of at least  85% correct on the test for absolute pitch. CCOM: students at the  Central Conservatory of Music, Beijing, China; all speakers of Mandarin.  ESM: students at Eastman School of Music, Rochester, New York; all  nontone language speakers.”

Looks like if you speak a tonal language and start learning music early, you are far more likely to have perfect pitch. (Separating causation from correlation may be tricky.)


References:

[1] Memory for the absolute pitch of familiar songs.
[2] Absolute memory for musical pitch: evidence from the production of learned melodies.

Quora: Why can most people identify a color without a reference but not a musical note?