In 1998, researchers from the University of Pennsylvania published a study that might strike you as kind of mean.

They took two people with severe amnesia, who couldn’t remember events occurring more than a minute earlier, and fed them lunch. Then a few minutes later, they offered a second lunch. The amnesic patients eagerly ate it. Then a few minutes later, they offered a third lunch, and the patients ate that, too. Days later, they repeated the experiment, telling two people with no short-term memory that it was lunch time over and over and observing them readily eat multiple meals in a short period of time.

This might seem like a somewhat trivial discovery, but it unveils a simple truth about why we eat. Hunger doesn’t come from our stomachs alone. It comes from our heads, too. We need our active memories to know when to begin and end a meal.

While our stomachs know exactly what food we’re eating (since they’re the organ responsible for processing it) our brains are a bit more easily tricked. In this month's Journal of Consumer Research, two studies on our brains and food open a crack into a depressing world of the eating brain's awful gullibility.

How Menus Trick Us

Calorie counts can be good things. Even if they don’t dramatically change our behavior, studies have shown that they gently nudge both foodies and restaurants toward lower-calorie fare. But a new study from JCR found that there’s an easy way to eliminate the benefit of calorie counts. If you organize all the healthy dishes into a single “low-cal” category, it ironically diminishes all of the positive effects of calorie-posting. Having a separate Health Menu lets people consider the Health Menu separately. They feel good that it’s there, and then they proceed to order the same fatty stuff they wanted to eat in the first place.