Wired shows us how making supper is good thing.

The Ikea Effect is a psychological bias first identified by Michael Norton, Daniel Mochon and Dan Ariely. The concept will make perfect sense to anyone who has struggled to put together a bookshelf based on an inscrutable set of instructions. Although the furniture might look like crap — I always have a few leftover screws — the flimsy assembly of molded plywood feels like a masterpiece. (That shelf isn’t supposed to be straight, right?)

In one study, the behavioral economists asked people to fold origami and then bid on their own creations. As expected, the subjects were consistently willing to pay more for their own folded paper creations. In fact, they were so enamored of their amateurish designs that they valued them as highly as origami made by experts.

It turns out that the Ikea effect also applies to food, at least in mice. The experiment was simple: Mice were trained to push levers to get one of two rewards. If they pressed lever A, they got a delicious drop of sugar water. If they pressed lever B, they got a different tasting drop of sugar water. (This reward was made with polycose, not sucrose.)

The scientists then started to play mind games with the mice, as they gradually increased the amount of effort required to get one of the sweet rewards. Although the mice only had to press the lever a single time to get the sugar water at the start of the experiment, by the end they were required to press the lever 15 times.

Here’s where things get interesting: When the test was over and the mice were allowed to relax in their home cage, they showed an overwhelming preference for whichever reward they’d worked harder to obtain. More lever presses led to tastier water. (The scientists measured these preferences in a variety of ways, including an analysis of “licking microstructure”. Preferred foods lead to a faster rate of initial licking and longer duration of “licking bursts.”)

The scientists conclude the paper by speculating on why such an effect might exist. They argue that the association of effort and deliciousness would have been an adaptive association back when calories were scarce, and we’d sometimes have to work hard to end up with a rather disgusting dinner: