Edge: Richard Thaler's Question

11/22/10.

THALER'S QUESTION

"The flat earth and geocentric world are examples of wrong scientific beliefs that were held for long periods. Can you name your favorite example and for extra credit why it was believed to be true?"

65 scientists answer:

http://www.edge.org/3rd_culture/thaler10/thaler10_index.html

Sample answers:

JONATHAN HAIDT

Psychologist, University of Virginia; Author, "The Happiness Hypothesis."

The closest thing to a persistent flat earth belief in psychology is probably the view that experiences in the first five years of life largely shape the personality of the adult. (The child is father to the man, as Freud said). It's now clear that experiences that affect brain development, such as some viral diseases or some head injuries, can indeed change adult personality. Also, extreme conditions that endure for years or that interfere with the formation of early attachments (e.g., an abusive parent) can also have lasting effects. But the idea that relatively short-lived experiences in the first few years — even traumatic ones, and even short-lived sexual abuse — will have powerful effects on adult personality... this just doesn't seem to be true. (Although such events can leave lasting traces on older children). Personality is shaped by the interaction of genes with experience; psychologists and lay people alike long underestimated the power of genes, and they spent too much time looking at the wrong phase of childhood (early childhood), instead of at the developmental phases that matter more (i.e., the prenatal period, and adolescence).

Why is early childhood such a draw when people try to explain adult personalities? I think it's because we think in terms of stories, and it's almost impossible for us NOT to look back from Act III (adulthood) to early childhood (act I) when we try to explain someone turned out to be a hero or serial killer. In stories, there's usually some foreshadowing in act I of events to come in act III. But in real life there is almost never a connection.


JUDITH HARRIS

Psychologist. Author, "No Two Alike."

The apple doesn't fall far from the tree. In other words, people tend to resemble their parents. They resemble their parents not only in physical appearance but also, to some degree, in psychological characteristics.

The question is: Why? Two competing answers have been offered: nature (the genes that people inherit from their parents) and nurture (the way their parents brought them up). Neither of these extreme positions stood up to scrutiny and they eventually gave way to a compromise solution: nature + nurture. Half nature, half nurture. This compromise is now an accepted belief, widely held by scientists and nonscientists alike.

But the compromise solution is wrong, too. Genes do indeed make people turn out something like their parents, but the way their parents brought them up does not. So nature + nurture is wrong: it's nature + something else.

The evidence has been piling up since the 1970s; by now it's overwhelming. And yet few people outside of psychology know about this evidence, and even within psychology only a minority have come to terms with it.

You asked for "examples of wrong scientific beliefs that we've already learned were wrong." But who is "we"? A few thousand people have learned that the belief in nature + nurture is wrong, but most people haven't.