The illusion of explanatory depth (IoED), Do you understand how a zipper works?
A recent book I picked up on a stroll through one of the last remaining book stores in Manhattan turned out to be interesting, eye-opening and frightening all at once. “The Knowledge Illusion” by Steven Sloman and Philip Fernbach is well written, interesting and very easily applied to one’s everyday life and humility.
The following is a part that really put some things into perspective for me.
Tickling the dragons tale
Nuclear warfare lends itself to illusion. Alvin Graves was the scientific director of the U.S. military’s bomb testing program in the early fifties. He was the person who gave the order to go ahead with the disastrous Castle Bravo detonation which wrecked absolute havoc and exploded with about a thousand times more power then what everyone expected. No one in the world should have understood the dangers of radioactivity better then graves. Eight years before Castle Bravo, in 1946, Graves was one of the eight men in a room in Los Alamos, the nuclear laboratory in New Mexico, while another researcher Louis Slotin performed a tricky maneuver the great physicist Richard Feynman nicknamed “tickling the dragon’s tail.” Slotin was experimenting with plutonium, one of the radioactive ingredients used in nuclear bombs, to see how it behaved. The experiment involved closing the gap between two hemispheres of beryllium surrounding a core of plutonium. As the hemispheres got closer together, neutrons released from the plutonium reflected back off the beryllium, causing more neutrons to be released. The experiment was dangerous. If the hemispheres got too close, a chain reaction could release a burst of radiation. Remarkably, Slotin, an experienced and talented physicist, was using a flathead screwdriver to keep the hemispheres separated. When the screwdriver slipped and the hemispheres crashed together, the eight physicists in the room were bombarded with dangerous amount of radiation. Slotin took the worst of it and died in the infirmary nine days later. The rest of the team eventually recovered from the initial radiation sickness, thought several died young of cancers and other diseases that may have been related to the accident.
How could such smart people be so dumb !?
It’s true accidents happen all the time. We’re all guilty of slicing our fingers with a knife or closing the car door on someone’s hand by mistake. But you’d hope a group of eminent physicists would know to depend on more than a handheld flathead screwdriver to separate themselves from fatal radiation poisoning.
Why was Slotin so reckless? We suspect it’s because he experienced the same illusion that we have all experienced; that we understand how things work even when we don’t.
Frank Keil a cognitive scientist who worked at Cornell for many years and moved to Yale in 1988. At Cornell, Keil had been busy studying the theories people have about how things work. He soon came to realize how shallow and incomplete those theories are, but he ran into a roadblock. He could not find a a good method to demonstrate scientifically how much people know relative to how much they think they know. Most methods he tried took to long or led participants to to just make stuff up. And then he had an epiphany. Next morning he grabbed Leo Rozenblit, who had been working with him on the division of cognitive labor and started mapping out the details. The questions were as follows:
- On a scale from 1 to 7, how well do you understand how zippers work?
- How does a zipper work. Describe in as much detail as you can all the steps involved in a zipper’s operation.
If you’re like most of Rozenblit and Keil’s participants, you don’t work in a zipper factory and you have little to say in the answer to the second question. You just really don’t know how zippers work. So when asked this question:
3. Now, on the same 1 to 7 scale, rate your knowledge of how a zipper works again.
This time you show a little humility by lowering your rating. After trying to explain how a zipper works, most people realize they have little idea and thus lower their knowledge ratings by a point or two. This demonstration shows that most people live in an illusion. When people rated their knowledge the second time, they were essentially saying “I know less then I thought.” It’s remarkably easy to to disabuse people of their illusion; you merely have to ask them for an explanation.
So next time one of your friends, colleagues or managers pretends to know it all; simply ask them to “explain” in detail. You will quickly put things into perspective.
