Our brains are exquisitely attuned to pinpoint and instantly react to a fixed range of dangers, such as snarling animals.

• 人脑的调频范围似乎是固定不变的：对那些显而易见的危险因素而言，它倒是相当精巧，极其灵敏，比如对那些会张牙舞爪的动物，人类都懂得高度戒备。