I’ve been working on a book of aphorisms—I’m writing my own aphorisms, and collecting my favorite aphorisms written by other people. That project keeps expanding, however—now I’m also collecting Proverbs of the Professions, my own Secrets of Adulthood, and quirky lists on odd subjects.

One of those lists contains examples of times when people have done something that, to me, shows a profound understanding of how people think and behave.

For instance, I’m fascinated by the actions of companies and organizations that have taken advantage of one particular quirk of human nature.

We often value things according to how much they cost us.

There’s a phenomenon called the “IKEA effect,” which gets its name from the popular Swedish store which sells furniture that people assemble themselves.

Studies show that if we feel that we’ve  made or created something ourselves, we view our creation more favorably. When we work harder on something, we tend to value it more highly.

This boost comes from the feeling of self-efficacy that we get from making something, and also from the fact that if we put effort into a task, we tend to believe that our work was well-justified.

IKEA isn’t the only company to take advantage of this effect. In the 1950’s, when instant cake mixes were introduced, they didn’t sell very well. After the mixes were changed so that a home cook had to mix in a fresh egg, the mixes became popular (that wasn’t the only change, but it was a factor).

These days, we can see the IKEA effect on meal-kit delivery services, where a subscriber gets a box of ingredients ready for assembly into a home-cooked meal. Or shoe companies that let customers design their own sneakers by choosing colors, stitching, and other features.

Parents sometimes use the IKEA effect when they ask their children to help prepare and cook food, because the parents see that children are more interested in eating something if they’ve helped make it.

We can think about the IKEA effect when creating any program, curriculum, or other change. If people feel that they’ve made a meaningful effort and contribution, they’re more likely to value the outcome.

It’s also useful to remember that we may over-value something because of the work we’ve put into it. We think that table is more valuable because we built it; we think that report is more useful because we wrote it.

We often value things according to how much they cost us—whether that’s in time, money, energy, or imagination.