Such work could solve the nature versus nurture debate, but is morally, ethically impossible


In "Too Hard for Science?" I interview scientists about ideas they would love to explore that they don't think could be investigated. For instance, they might involve machines beyond the realm of possibility, such as particle accelerators as big as the sun, or they might be completely unethical, such as lethal experiments involving people. This feature aims to look at the impossible dreams, the seemingly intractable problems in science. However, the question mark at the end of "Too Hard for Science?" suggests that nothing might be impossible.

The scientist: Steven Pinker, Harvard College Professor and Johnstone Family Professor in the Department of Psychology at Harvard University.

The idea: One of the oldest controversies in psychology is the nature versus nurture debate. Are innate qualities more or less important than the effects of experience on how a person thinks and behaves?

There is one morally repugnant line of thought Pinker strenuously objects to that could resolve this question. "Basically, every nature-nurture debate could be settled for good if we could raise a group of children in a closed environment of our own design, they way we do with animals," he says.

For instance, renowned linguist Noam Chomsky of the Massachusetts Institute of Technology proposed that humans possess an innate set of linguistic principles dubbed "universal grammar" that guides and constrains the acquisition of language. This idea "could be tested by exposing children to artificial languages that violate the universal grammar and seeing whether they resist learning them as designed and instead assimilate them to the universal principles," Pinker says.

"The biological basis of sex differences could be tested by dressing babies identically, hiding their sex from the people they interact with, and treating them identically, or better still, dividing them into four groups — boys treated as boys, boys treated as girls, girls treated as girls, girls treated as boys," he notes.

"This is the tip of an iceberg," Pinker says. "One could spend many hours fantasizing about how to resolve every controversy about nature and nurture."

The problem: "There's no end to the ethical horrors that could be raised by this exercise," Pinker says.

"In the sex-difference experiment, could we emasculate the boys at different ages, including in utero, and do sham operations on the girls as a control?" Pinker asks. "In the language experiment, could we 'sacrifice' the children at various ages, to use the common euphemism in animal research, and dissect their brains?"

"This is a line of thought that is morally corrosive even in the contemplation, so your thought experiments can go only so far," he says.

The solution? Instead of performing such unacceptable experiments on children, psychologists commonly seek cases where the circumstances they want to learn more about have occurred. For instance, when exploring how children acquire language, "these would include deaf and blind children, children who have suffered from brain damage or inherited language disorders, children who have been raised in various kinds of isolation by depraved parents, and children of unusual communities such as historical plantation colonies in which no common language is spoken across the community," Pinker says.

Image of Steven Pinker from his Web site.


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About the Author: Charles Q. Choi is a frequent contributor to Scientific American. His work has also appeared in The New York Times, Science, Nature, Wired, and LiveScience, among others. In his spare time he has traveled to all seven continents. Follow him on Twitter @cqchoi.

The views expressed are those of the author and are not necessarily those of Scientific American.