I mentioned earlier in this book that there are five main reasons why human behaviour often departs from what we think of as conventional rationality. The first of these is signalling, the need to send reliable indications of commitment and intent, which can inspire confidence and trust. Cooperation is impossible unless a mechanism is in place to prevent deception and cheating; some degree of efficiency often needs to be sacrificed in order to convey trustworthiness or to build a reputation.
