Our obsession with marijuana's mystifying powers goes back a long time; though its first documented use was in 2727 BC, there's some indication that our ancestors cultivated cannabis plants in the earliest days of agriculture. Since then, marijuana has spread around the world, used for medicine, religious purposes, or recreation by almost every culture. Clearly, pot does something for us. But until recently, scientists didn't have the technology to really figure out how pot makes us feel the way it does (other than testing it anecdotally, of course).

It gives us the munchies

Tetrahydrocannabinol (THC), the active compound in marijuana, binds to special pathways called cannabinoid receptors, found on the membrane of cells in the brain and elsewhere in the body. When these receptors are activated, they change the function of a certain type of hunger-regulating neuron, according to a study conducted on mice and published earlier this year. Normally when those neurons are activated, they tell mice that they're not hungry. But when the cannabinoid receptors are turned on, the neurons tell the mice to chow down.