As a college senior, I took an introductory philosophy course. It was a big class—around 50 students. On the first day of class, my fellow students and I filed into the classroom to meet our professor.

The professor began by welcoming each of us to class. Individually. By name. Row by row, he looked each student in the eye and greeted everyone by name.

This got our attention.

It turned out he’d used a little-known feature in the school’s computer system to access the class roster along with each student’s ID photo. He’d then spent who-knows-how-long memorizing each student’s name and face. After a first day like that, I was not surprised when Intro to Philosophy proved to be one of the most engaging and stimulating courses I took in undergrad.

It turns out that there’s a term for this kind of thing, and it’s something we should be familiar with if we want to maximize our impact on others.

Costly Signals

In biology and economics, a message to others that’s expensive to send (in terms of money, time, etc.) is known as a costly signal. Costly signals eat up resources, and that makes them unlikely to have been sent casually. It takes a lot of time to memorize the names and faces of 50 college students before you’ve met them, and there’s no way to fake it.

We send costly signals all the time:

  • A handmade gift says “Our friendship is so valuable to me that I spent several hours making this for you.”
  • A well-manicured lawn says “I care about my property values (and yours). I’m a team player (and maybe a bit of a traditionalist).”
  • An advanced degree says “I’ve spent years becoming an expert in my field. You can trust what I say.”

Talk is cheap. If you’re trying to send a message to others, it’s worth taking some time to think about how you can make your sincerity blindingly obvious.