He’s very excited as he runs back to tell his clan about it. Dopamine creates the energy to run back, and the memory to find the spot again. Then its job is over. Your ancestor might feel happiness in other ways: His serotonin might surge when he thinks of the respect he will get for his find. His oxytocin might activate when he thinks of the shared pleasure of feasting. But his dopamine will dip unless he finds an even bigger run of fish. He will look hard for more fish because he knows how good it feels.
