Underlying Paul Bloom’s insightful essay is a bias that permeates human attitudes toward authenticity. There is something less worthy about a copy or a duplicate even when it is virtually indistinguishable from an original, whether an object, a living thing, a person, a song, or an idea. Why is this? After all, some things get better with modification.

Originality appears to be important, and, as a father of two teenagers, I can attest to young people’s need to be seen as unique. My teens often accuse each other of copying the other’s preferences and mock those who follow trends. The irony of course is that the desire to be different is itself a trend. Teenagers are torn between wanting to belong and wanting to be different.

The issue of self-construal resonates with another theme running through Bloom’s piece, namely the extended self—we use possessions to signal our status to others. William James effectively said that we are what we own, and marketing strategies strive to connect our idealized sense of self with products for sale. Bloom addresses this as an issue of signaling but does not explicitly discuss a topic clearly relevant to the value that we place on possessions: essentialism.

Marketing strives to connect our sense of self with products.

We prefer originals because we invoke the intuitive notion of essentialism, which holds that there is some underlying property of objects that confers identity and that in some instances is almost contiguous with quality. For example, one polystyrene cup is pretty much the same as another so long as it functions. However, if it turns out to be the last polystyrene cup Elvis Presley drank from, then it becomes irreplaceable. But there is more to this authentic value than history. For many of us, though not all, authenticity evokes the notion of essential contagion. The cup that touched Elvis’s lips would be an example of positive contagion—something to covet and pay good money for. As Bloom notes, memorabilia collecting is motivated by aspects of positive contagion, which explains why collectors do not want their celebrity keepsakes washed. The flipside of memorabilia is murderabilia, the trade in items connected with evil acts. A few perverse people are attracted to the notion of owning and touching items associated with violent crime.

A cynic might dismiss both positive and negative essences as nothing more than associative learning, arguing that we experience the pleasure or revulsion because of associations rather than any intuitive sense of actual contamination. But while associations may be part of the explanation for our emotional reactions, consider how you would respond to holding two books in your hands, one a biography of Adolf Hitler detailing the atrocities he was responsible for and the other a cookbook that he used when preparing schnitzel for Eva Braun. According to association theory, the biography should trigger more negative reactions because of the explicit descriptions of war crimes. In contrast, the cookbook says nothing about Hitler’s crimes, but I suspect that most people would find it more offensive to hold. It is as if you would be making direct contact with the dead fuhrer’s hands.

What could possibly explain such behavior? Paul Rozin, the psychologist who pioneered many of these irrational-contagion studies, argues that it is a legacy of a biological defense mechanism. After all, we do not know why someone is a psychotic killer. Maybe it is due to some pathogen that we intuitively avoid.

Essentialism permeates many aspects of culture, including concepts of purity and moral behavior, which vary across the globe. For example, although India’s caste system has been banned for some time, untouchables are still recognized in rural areas, with all of the associated rules about what amount and type of contact with others is acceptable. In contrast to the West, India is often described as a collectivist society where the sense of self is reflected not in the individualistic status one has achieved but rather in the interdependence one has demonstrated. That might explain why Darren Julien, founder and president of one of the world’s largest celebrity memorabilia auction houses, notes that, despite increasing demand for investment opportunities in Eastern countries, interest in memorabilia is not yet as strong as in the United States. This does not mean that essentialism is entirely constructed by culture, but rather that the ways it manifests reflect the values cultures place on items as a measure of individualism. It seems likely that sacred sites and objects will also generate authentic biases that evoke some deeper metaphysical property like an essence.