kahnemanandtversky

The first time I met Princeton University (former UC-Berkeley, former University of British Columbia) psychology professor Danny Kahneman and the only time I met the late Stanford University psychology professor Amos Tversky was at a decision making conference in Chicago in June, 1988. I was finishing up my dissertation on “ambiguity and rationality” at the University of Pennsylvania in Philadelphia and getting ready to move to Eugene to work as an assistant professor of psychology at the University of Oregon. I was 26.5 years old.

I had been arguing with “kahnemanandtversky” (as Columbia University marketing professor Eric Johnson aptly puts it – it’s one meme, ergo it should be one word) in my mind for five years. I was eager to fight with the real mccoys.

Even though at the time, no one imagined that Dr. Kahneman would win the 2002 Nobel prize in economics, most of other prominent experimental decision scientists (e.g., Paul Slovic, Sarah Lichtenstein, Lola Lopes, Baruch Fischhoff, May Bar-Hillel, Dick Thaler, Robin Hogarth, George Loewenstein, Frank Yates, Reid Hastie, Robyn Dawes) understood that Danny and Amos were superstars. There was a lot of competition to talk to both of them.

I spotted Danny first. I hovered in his vicinity, waiting for the tiniest break in the steady stream of people wanting to talk to him. Finally, I saw my chance and briskly approached him. He read my name tag.

“Hello, Deborah. It’s nice to meet you. What sort of research do you do?”
”I criticize what you do.”

He smiled and graciously listened to my two minute pitch on why he and Amos were totally off base about a statistical brain teaser involving Linda, a notorious feminist bank teller. After a few minutes, he praised me for my effort but candidly confessed that like others who had tried (e.g., Lola Lopes), I had failed to convince him that he and Amos were wrong about Linda. He cordially drew the conversation to a close and walked away. One thing I have to say about Dr. Kahneman – he has treated me like a peer since the moment I met him.

I don’t have as vivid a memory of the moment I met Amos Tversky at that 1988 conference in Chicago that was a tribute to the late University of Chicago Graduate School of Business professor Hillel Einhorn, who collaborated with Robin Hogarth. Einhornandhogarth never became one word like kahnemanandtversky. Of course, neither did lichtensteinandslovic, for that matter.

I remember sitting at a table for a long time arguing with Amos about Linda the feminist bank teller. I understood that the reason Amos was willing to debate Linda with me for pi-squared as many minutes as Danny was because he thought he had a non-zero chance of scoring tuchus.

When I got to the University of Oregon, I became friends with Jennifer Freyd, who had been an undergraduate at the University of Pennsylvania and a grad student at Stanford. I told her about how Amos (a Stanford prof) had sort of hit on me at the Einhorn conference. In hindsight, it seems naïve to me that I was so shocked and indignant. It suggests that in my five years as a graduate student in the psychology department at the University of Pennsylvania, I did not experience sexual harassment. This is kind of a compliment, I guess, to Jon Baron, John Sabini, Bob Rescorla, Dave Premack and the other professors I interacted with at Penn.

Jennifer listened to the story about my encounter with Amos. She said something to the effect of “In my four years at Stanford, he never looked above my clavicle or below my sternum.” I can’t say that I blame him, actually, because…aw, never mind.

Of course, I don’t really want to talk about Danny, Amos and Jennifer. I want to talk about Linda and what she means to me.

The gist of the research by Kahneman and Tversky et al. is that the way that people think about statistics and risky decisions deviates from mathematical models of how statisticians and economists allege we should think about statistics and risky decisions.

There are two reasons for a discrepancy between how most people think and mathematical models that allegedly describe the way all people should think. One reason is that we have biases and flaws in our thinking, especially our mathematical thinking. A second reason is that there are biases and flaws in the alleged models of rationality developed by statisticians and economists.

Kahneman and Tversky deny the possibility of the second reason. It’s not too much of a stretch to say that their most virulent critic (Gerd Gigerenzer) denies the possibility of the first reason. Like Lopes (and Einhorn and Hogarth and Slovic and Lichtenstein and probably Hastie and Yates, for that matter), I believe both reasons have validity.

A few months ago, I thought of a way to explain the gist of my answer to the question “How can Kahneman and Tversky be so right and so wrong at the same time?” without having to bring the audience up to speed on all of the concepts necessary to understand their research (e.g., probability, expected value, heuristic).

I have this t-shirt with the number pi written in tiny numbers corresponding to the first few hundred digits of the infinite number of digits in pi. My mother bought it for my nephew. When she showed it to me and announced the intended recipient, I said “Over my dead body” and she changed her mind and gave it to me.

When a random person comments on my pi tee shirt, 98.6% of the time I say “Hey, I was in a pi-eating contest last week. I got through 3.1415 but I couldn’t eat nine.”

Once, someone heckled me mid-joke. After I said “I was in a pi eating contest last week.” he said “I can tell.”

Another guy let me finish and then said “Better luck next time.”

The other 1.4% of the time, I say this, which captures the gist of my doctoral dissertation and 20 years of academic research.

You know, mathematicians say that pi is an irrational number. Pi is used to estimate the weight and describe the shape of quasi-spherical objects like the sun, moon and earth not to mention human heads and living cells. It’s used to quantify quasi-cylindrical objects like arms, legs and large intestines.

Mathematicians say the basis for quantifying, measuring and thereby, better understanding important objects in the universe and our bodies is irrational. I say mathematicians are irrational.