Honest signals

How did humans coordinate before we had sophisticated language capabilities? Pre-linguistic social species coordinate by signaling, and in particular 'honest signals' which actually cause changes in the listener. I will describe examples of human behaviors that are honest signals, and how they can be used to accurately predict and shape the outcomes of interactions (medical compliance, negotiation, trust assessment, depression screening, etc.). Understanding how human decision making is influenced by these pre-linguistic patterns of signaling also leads to very different ways to build incentives to change. In a recent trial we were able to change population behaviors using a social signaling strategy, and achieved twice the efficiency of standard behavior change schemes.