We’ve all been there. The morning you overslept and have to skip breakfast in order to make it to work on time. The meeting that runs long and makes lunch a distant dream. The snack drawer that’s unexpectedly empty right as you’re looking for an afternoon boost. Going without food – especially unexpectedly – can have all sorts of detrimental effects on us. From slowed cognitive functioning, to the dreaded “hangry” feeling of hunger-inspired irritability, managing hunger is never as easy as we’d like. But why is it so difficult?

Recent research into the hierarchies of needs in mice showed that hunger outweighs all other motivations. When mice who were hungry and thirsty were presented with the option to choose between sating one of the two needs, they chose food over water. Likewise, when mice were presented with the option to choose between sating hunger, or sating a need to socialize, they still chose food. Even fear and feelings of safety were not enough to overwhelm the need for food, as mice would choose to leave areas that were judged “safe” and venture into areas that smelled of predators in order to obtain food when hungry.

Mice are frequently used as analogs for humans in tests like these, because they closely resemble humans on a genetic, biological, and behavioral level. And much like humans, mice evolved to ensure that their most pressing needs were the ones they addressed first. Being hardwired to address hunger makes sense. While a human can go longer without food than without water, the food we consume contributes to our water intake as well, making food something that can satisfy multiple needs, while water only satisfies a single need. Likewise, while socialization is something humans need in order to function properly, it takes longer for a deficit to develop and have a comparably negative impact. Even safety can easily be outweighed when the possibility of danger is measured against the certainty of failing to fulfill a survival need.

So the next time you struggle with a┬ámid-day caloric drop, remember, that “hangry” feeling is just a product of evolution, reminding you to deal with the most important things first.


Important Message