costly signal

Verification Burden

Proving a trait requires an act that an unqualified person would find too expensive. The costly signal acts as a filter that separates those who have the trait from those who only claim it. This is why a simple promise is never enough in a high stakes arrangement.

Sender Cost

Resources must be consumed to make the message count. When a costly signal is sent, the sender loses hours or money that they cannot get back. This loss is what makes the signal credible to the counterparty who receives it.

The sacrifice of capacity proves that the sender is not acting for a short term gain but is invested in the long term outcome of the arrangement.

Reliability Anchor

Trust is built on the fact that the sender paid to be heard. A costly signal creates a record of investment that the observer can check against their own risk. It is the only way to move past the ambiguity of spoken words.