Eh. We've got a close enough approximation. Sci-fi-esque example below. The more things humans collected, the safer their genes were, and the higher the dopami

Eh. We've got a close enough approximation. Sci-fi-esque example below. The more things humans collected, the safer their genes were, and the higher the dopamine hit. Many humans took this to the logical end, collecting things at the expense of all else, including the safety of other humans. This led to severe poverty of all humans not wired to collect more things, which decreased their reproductive fitness. Over time, the human race in aggregate continued to become more effective at collecting things, until they had wiped out all other life and all viable material was turned to drugs. The end.