Editor's note: Paul Bloom is professor of psychology and cognitive science at Yale University, where he directs the Mind and Development Lab. Follow him at twitter.com/paulbloomatyale. Bloom spoke at the TED Global conference last month in Edinburgh, UK. This article is adapted from his book, "How Pleasure Works" (Norton, 2010). TED is a nonprofit dedicated to "ideas worth spreading" which it makes available on its website.

(CNN) -- Some questions about pleasure have easy answers. We know why humans get so much joy from eating and drinking. We know why sex is often fun, and why it can be such a delight to look at a baby's smiling face and listen to a baby's laugh. All of this follows from the logic of natural selection.

Animals like us need food and water to survive, need sex to reproduce, and need to attend to and care for our children in order to pass on our genes. Pleasure is the carrot that attracts us to these reproductively essential activities.

But many human pleasures are far more mysterious. Some men pay good money to be spanked by prostitutes. The average American spends over four hours a day watching television. The thought of sex with a virgin is intensely arousing to many men. Abstract art can sell for millions of dollars. Young children enjoy playing with imaginary friends and can be comforted by security blankets. People slow their cars to look at gory accidents and go to movies that make them cry.

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How do we explain these weird, and uniquely human, pleasures? I don't think that any of them are biological adaptations. Instead, they are best understood as accidental byproducts of a certain way that we make sense of the world around us.

We unconsciously believe that things, people, and events have invisible essences that make them what they are. Experimental psychologists have argued that this essentialism underlies our understanding of the physical and social worlds, and developmental and cross-cultural psychologists have proposed that it is instinctive and universal. We are natural-born essentialists.

In my book, I proposed that this essentialism not only influences our understanding of the world, it also shapes our experience of the world, including our pleasures. The enjoyment we get from something is powerfully influenced by what we think that thing really is. This is true for intellectual pleasures, such as the appreciation of paintings and stories, and it is true as well for pleasures that seem simpler and more animalistic, such as the satisfaction of hunger and lust.

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I am not denying that we are influenced by other factors as well. Of course, the chemical composition of wine affects how much we like it; the geometry of a face affects how attractive it is, the fat content of a steak affects how much we enjoy eating it. But what I would argue is that there is always more to our pleasure than the physical nature of things.

We are always influenced by our beliefs. Pleasure is always deep. For a painting, it matters who the artist was; for a story, it matters whether it is truth or fiction; for a steak, we care about what sort of animal it came from; for sexual desire, we are strongly affected by who we think our sexual partner really is, and the nature of our relationship with that person.

Wine is a perfect example of this. You can take the same wine and label it in different ways, and this affects how people, including experts, experience it. In one study, a Bordeaux was either labeled as a "grand cru classe" or as a "vin du table."

Forty experts said the wine with the fancy label was worth drinking, while only 12 said this of the cheap label. The grand cru was "agreeable, woody, complex, balanced and rounded," while the vin du table was "weak, short, light, flat and faulty."

In another study, scientists scanned people's brains while they tasted wine. It was always the same wine but it was described as costing either $10 or $90. People reported liking the wine more when it was described as expensive -- and the parts of the brain associated with pleasure and reward were far more active.

It gets worse. My favorite recent finding was reported in a working paper called "Can People Distinguish Pâté from Dog Food?" They can't. If you grind up a product called "Turkey & Chicken Formula for Puppies/Active Dogs" in a food processor and garnish it with parsley, people cannot reliably distinguish it from duck liver mousse, pork liver pâté, liverwurst, and Spam. But, of course, if you know what you are eating, dog food and pâté are entirely different taste experiences.

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I hope these thoughts spark debate over why we like what we like. In a recent discussion, the psychologist Paul Rozin pointed out that if you look through a psychology textbook you will find little or nothing about sports, art, music, drama, literature, play, and religion. These are wonderful and important domains of human life, and we won't fully understand any of them until we understand pleasure.

The opinions expressed in this commentary are solely those of Paul Bloom.