The motive of willingness-to-pay (WTP) was considered to be selfish only in the past and recently altruism was added as the motive. Decisions based on concerns for others tend to be evaluated from the viewpoint of altruism in Contingent Valuation Method (CVM). In this paper, the decisions are considered to be based on reciprocal and altruistic motives. Payment motive mechanisms of social decisions based on reciprocity were examined. An individual's expectation for reciprocal action from a planner appears to be included in his social decision. According to the characteristics of reciprocity, we suggest that individual states of WTP are adversely affected when a person has hostile impressions of planner's action or behavior. In addition, this paper describes the overall composition of payment motive and the status of reciprocity.

JEL classification: R11, R22, R58