As a young and fair-weather gamer, I loved playing Super Mario Brothers because it was my older brother's favorite game, and I wanted to be just like him. I can still hear the 8-bit theme song in my head, and I'm guessing you can too, if you played Mario as a kid. "Bah dat dat doo dat dat doo," goes the classic, repetitive, 1985 jam. The ubiquity of those notes in many of our childhoods was as constant as a hug from grandma, a pack of Gushers after school, or Saturday morning cartoons. Retro games like Mortal Kombat, Street Fighter, and The Legend of Zelda are comfort food for gamers.

A team of researchers from DeepMind, University College and Harvard University has found that lessons learned in applying learning techniques to AI systems may help explain how reward pathways work in the brain. In their paper published in the journal Nature, the group describes comparing distributional reinforcement learning in a computer with dopamine processing in the mouse brain, and what they learned from it. Prior research has shown that dopamine produced in the brain is involved in reward processing--it is produced when something good happens, and its expression results in feelings of pleasure. Some studies have also suggested that the neurons in the brain that respond to the presence of dopamine all respond in the same ways--an event causes a person or a mouse to feel either good or bad. Other studies have suggested that neuronal response is more of a gradient.