Average and unique

I thought this was an interesting NPR interview regarding what it really means to be average (is anyone really?) or unique (is anyone not?). Most of it is with regards to education, but the points made about statistics would seem to apply to general categorizations we make of people (e.g. introvert/extrovert), but also -- to the extent that all psychological criterion take into account the culture of those they are being applied to (pedophilia is not going to mean the same in a culture in which the average marriage age is 13, sadness doesn't necessarily mean your depressed if you are just expressing a culturally appropriate amount of grieving, criminality in one culture is entrepreneurship in another, etc.)  -- to the world of psychology.

Rose talked with us about his new book: The End Of Average: How We Succeed in a World That Values Sameness.

The opening example you use in the book is that in the 1940s, when the Air Force designed cockpits based on the average measurements of the pilots, there were an unacceptable number of crashes. But when they went back and measured thousands of pilots, across 10 body dimensions, they found that zero of them even came close to the "average" on all 10. So they concluded that they had to redesign the seats and so forth to be adjustable to each person.

Body size is a very concrete example of what I call jaggedness. There is no average pilot. No medium-sized people. When you think of someone's size you think of large, medium, small. Our mass-produced approach to clothing reinforces that. But if that were true you wouldn't need dressing rooms.

So dimensions like height and weight and arm length and waist circumference ...

Yes, they're not nearly as correlated as you would think. Height is one-dimensional, but size isn't. People are jagged in size, in intelligence, everything we measure shows the same thing.

I'm going to quote a line from the book, said to psychologist Paul Molenaar, who is arguing for a greater focus on individual difference: "What you are proposing is anarchy!" How do you make decisions about people if you can't use statistics and cutoff scores and compare them to averages?

People feel like if you focus on individuality, everyone's a snowflake, and you can't build a science on snowflakes. But the opposite has been true.

It's not that you can't use statistics, it's just that you don't use group statistics. If I want to know something about my daily spending habits, one straightforward way would be to collect records of what I spend every day. To take an average for myself would be perfectly fine.

So you can generalize across time, but not across people?

We've got to let go of putting a group into a study and taking an average and thinking that's going to be close enough to universal insight.

Now we have something better. We have a natural science of individuality that gives us a surer foundation. We've gotten breakthrough insights in a whole range of research, from cancer to child development.