Comments on: Biases are Fattening

By: Tiiba

Tiiba — Thu, 09 Aug 2007 18:57:35 +0000

My problem is that I buy a snack, see that it’s only a hundred calories, and decide to eat five… And now I have a Twinkie in my gut. What is that called? Perhaps “per-unit” bias?

This can also be generalized to procrastination and financial wastefulness. A dollar here, a minute there, soon the project is late and over budget.

By: _Gi

_Gi — Tue, 03 Jul 2007 17:32:48 +0000

“We can certainly learn more elaborate programs like “take unit; consume until full; leave the rest”, ”

This maybe much harder than you think. There is a several minutes lag between satiation and your awareness of it.

By: Anders Sandberg

Anders Sandberg — Tue, 03 Jul 2007 07:21:33 +0000

Mostly an artifact of the initial study (i.e. availability bias). I’m pretty certain unit bias is much more general. I think an easy way to test it would be to look at how people consume other resources like post-its and check whether consumption tends to match package size. The really interesting thing would be to look for conceptual unit bias, where it might round our thinking towards the nearest integer number of convenient units.

By: Nathan Iver O'Sullivan

Nathan Iver O'Sullivan — Mon, 02 Jul 2007 23:17:05 +0000

Based on the discussion so far, the unit bias appears to be almost exclusively a food bias. Why?

By: Floccina

Floccina — Mon, 02 Jul 2007 21:18:54 +0000

I worked in restaurant that sold Pizza and I always thought it silly that many people would ask how many pieces the pizza had (we only had one side Pizza was just a side line). Some people would ask the size and I would give them the diameter some would be happy with that but others would ask how many pieces is that. I wanted to say that we will cut it into as many pieces as you want but I did not.

By: Nathan Iver O'Sullivan

Nathan Iver O'Sullivan — Mon, 02 Jul 2007 14:14:29 +0000

Michael, I think Andrew’s point is that the 36oz is actually a worse deal because of our unit bias.

By: Michael Schwaeber

Michael Schwaeber — Mon, 02 Jul 2007 13:55:53 +0000

What about the rather favorable marginal cost of the expanded/supersized unit? For example, buy a small 20oz soda at a movie theater for $2.50 or a medium 36oz size for only a quarter more.

By: Andrew

Andrew — Mon, 02 Jul 2007 01:55:41 +0000

This reminds me of an insight I had several years ago which I used to tell the students in my decision analysis classes. They were always skeptical but maybe now with research behind me on this, they’ll believe me.

Anyway, here goes:

When I was younger, people used to complain about candy bars getting smaller and smaller. (For example, Stephen Jay Gould has a graph in one of his books showing the size of the standard Hershey bar declining from 2 ounces in 1965 gradually down to 1.2 ounces in 1980, and for that matter I can recall tunafish cans gradually declining from 8 ounces to 6 ounces.) And I remember going to the candy machine with my quarter and picking out the candy bar that was heaviest–I don’t remember which one–even if it wasn’t my favorite flavor, to get the most value for the money.

But now I realize that, rationally, candymakers should charge more for smaller candy bars. The joy from eating the candy is basically discrete–I’ll get essentially no more joy from a 1.7-ounce bar than from a 1.4-ounce bar. But the larger bar will be worse for my health (no big deal if I eat just one, but with some cumulative effect if I eat one every day, similarly with the sodas and so forth). And, given the well-known fact that nobody can eat just part of a candy bar, I get more net utility from the small bar, thus they should charge more.

By: Anders Sandberg

Anders Sandberg — Sun, 01 Jul 2007 12:01:26 +0000

I was referring to the nutrient labels. Tabular information is “statistical information” to most people. A surprising number of people have a hard time extracting the relevant information from even a simple table.

The amusement ride example from the paper is indeed rather bad when you start thinking about it. But that doesn’t make unit bias irrelevant. Most people seem to settle for one iteration of the bumper car ride even when there is no queue and they can get out if they wish.

And thank you, Hopefully Anonymous. I’m glad that I can contribute something.

By: TGGP

TGGP — Sun, 01 Jul 2007 08:04:43 +0000

“people take one ride on an amusement park ride regardless of whether it is 1 or 5 minutes long”

Well, are you going to stand in line twice?

Even more ridiculous, are you going to “waste” or “leave over” part of the ride by exiting before it comes to a complete stop!