What drives us to trust someone we just met? Did we eat spaghetti for lunch because we saw our colleague eat spaghetti? Can we become happier when we are nicer to our neighbors? How does the content of our breakfast have anything to do with our social interactions throughout the day? Research from different disciplines such as economics, psychology and neuroscience have attempted to investigate the motives and modulators of human decision making. Our decisions can be flexibly modulated by the different experiences we have in our daily lives. These modulations can occur through our social networks, through the impact of our own behavior on the social environment, but also simply by the food we have eaten. Here, I will present a series of recent studies from my lab in which we shed light on the psychological, neural and metabolic motives and modulators of human decision making.