I would have made almost the reverse claim: humanity has a well-defined threat-response instinct and we are constantly on the lookout for threats to ourselves,

I would have made almost the reverse claim: humanity has a well-defined threat-response instinct and we are constantly on the lookout for threats to ourselves, our family, our society. Like a social immune system. If there aren't any serious threats we can't just relax and live our lives - we have to invent some problems to worry about. Hence the never-ending stream of overblown largely imaginary threats - killer bees, crack babies, flag-burning, overpopulation, declining fertility, pesticides (eg, alar), GMOs, global cooling, global warming, "peak oil", fracking. There is almost no correlation between how serious a threat is and how much we worry about it. In fact, the correlation is often inverse - we worry far more about child abductions and school shootings now that they almost never happen than we did when they happened more. Because if something happens all the time it's not "news". So a school shooting in any crappy city anywhere in the US prompts national headlines and gets us ALL worrying about whether our children are safe, whereas kids dying in auto accidents or house fires or drowning in swimming pools in much larger numbers don't even make the local newscast.