Neuroscientists have found that environmental cues trigger immediate responses in the human brain even before we are aware of them. As you move into a space, the hippocampus, the brain’s memory librarian, is put to work immediately. It compares what you are seeing at any moment to your earlier memories in order to create a mental map of the area, but it also sends messages to the brain’s fear and reward centers.

To read more of this Happy City excerpt, read on in The Atlantic: Why We’re Sometimes Kind Without Reason