I just had a fight with my landlord. A few days back, a young man stared over the front wall at his daughter, who recently turned twelve (a traumatic age for the parents if not the girl!). The landlord responded by raising the wall significantly, so that neighbours can no longer lean over it to chat with his family. He then started topping the wall with broken glass. When I protested, he replied that it was a temporary measure until he could afford a metal grill. He felt it was necessary because the man he was paying to raise the wall had pointed out that people could jump over it. Well, yes, they could. They could also easily walk in the gate, which is left unlocked all day. In fact, all kinds of terrible things could happen, but we have a bad habit of focusing on the more unlikely ones and ignoring the real threats, such as climate change and peak oil. I did convince him to get rid of the broken glass, but when I suggested getting a dog for security instead, he was afraid that the dog could scratch or bite his son and give him rabies. Meanwhile, the more we withdraw behind walls and other barriers, the less strong the community becomes and the more there is to fear. Perhaps it’s all yet another illustration of how human brain development has lagged behind the growing complexity of society: we fear what we shouldn’t, don’t fear what we should, and in the process often do exactly the wrong thing.