Finally, there’s a scientific explanation as to why your older brother never once shared anything with you no matter how many times you shared with him. As it turns out, people who exhibit selfishness without any sense of quid pro quo after someone does a nice deed for them may be wired differently neurologically. Researchers call these types "Machiavellians," who show unusually high activity in the inhibition part of the brain during moments of kindness, therefore inhibiting them from reciprocating the fairness being shown to them. So if "Machiavellian" people can’t help their selfishness, what’s the best way to handle their rude, calculating behavior? As the old adage goes, "Kill them with kindness," which will cause their synapses to go into overdrive and leave them befuddled over how to respond to your behavior, says researchers. How do you deal with selfish types? Sound off in the comments!