Willingness to pay, Contingent valuation, Cheap talk, Protest response, Field experiment, Air pollution, D6, C9,

Up to now, the starting point bias has generally been considered to be a homogeneous phenomenon. In this article, we treat anchoring as an unobserved heterogeneous phenomenon. Our contribution is twofold. First, we show analytically and by way of simulations that assuming homogeneous anchoring can be hazardous and lead to misspecifications. Second, we propose an econometric model that starts with a dichotomous question and then uses an open-ended question. We finally apply our model to a contingent valuation survey on air quality. Our results suggest that how anchoring is modeled in empirical studies deserves more attention. Copyright 2007, Oxford University Press.

In this paper, we propose a behavioural approach to determine the extent to which the consumer/citizen distinction aects interpretations of monetary values. We perform a eld experiment dealing with air pollution, where some (randomly selected) subjects are given the opportunity to behave politically by signing a petition for environmental protection prior to stating their private preferences in a standard contingent valuation exercise. We show that the petition has the potential to inuence respondents' willingness to pay and that whether the eect is negative or positive depends on the degree of (dis)similarity between the petition and the scenario in which willingness to pay are elicited. We interpret the results using the theory of commitment borrowed from social psychology.

Stated preference surveys are usually carried out in one session, without any follow-up interview after respondents have had the opportunity to experience the public goods or policies they were asked to value. Consequently, a stated preference survey needs to be designed so as to provide respondents with all the relevant information, and to help them process this information so they can perform the valuation exercise properly. In this paper, we study experimentally an elicitation procedure in which respondents are provided with a sequence of different types of information (social cues and objective information) that allows them to sequentially revise their willingness-to-pay (WTP) values. Our experiment was carried out in large groups using an electronic voting system which allows us to construct social cues in real time. To analyse the data, we developed an anchoring-type structural model that allows us to estimate the direct effect (at the current round) and the indirect effect (on subsequent rounds) of information. Our results shed new light on the interacted effect of social cues and objective information: social cues have little or no direct effect on WTP values but they have a strong indirect effect on how respondents process scientific information. Social cues have the most noticeable effect on respondents who initially report a WTP below the group average but only after receiving additional objective information about the valuation task. We suggest that the construction and the provision of social cues should be added to the list of tools and controls for stated preference methods. "Faced with the choice between changing one's mind and proving that there is no need to do so, almost everyone gets busy on the proof." Galbraith, 1971.