# Fitness is a group measurement function Things which appear to be good for the *individual* are not necessarily selected for, like selfishness (which benefits you by harming those around you). Things which appear bad for the individual are not necessarily selected _against_, like altruism (the reverse): Getting yourself killed is (obviously) not good *for you*. So why did this behavior develop? Why would evolution keep it around? The reason is evolution isn't concerned _with you_. It doesn't even care about you. It cares about _the population_. # Danger weeds out the weak Sure, this is a very noisy selection mechanism. Certain kinds of danger will kill _anybody_. But many kinds of danger will kill weak or stupid elves much more readily than more resilient individuals. Accordingly, a genetic predisposition to hiding behind mommy will tend to make it easier for less fit elves to survive long enough to spread their genes. In contrast, a predilection for adventurous mischief will tend to get less hardy or intelligent elves killed at a higher rate. In other words, this gene is bad for _individuals_ but good for _the population_ because it checks the spread of, and indeed works to eliminate, other genes which are harmful.