Grantee Research Project Results
Final Report: Towards a Social Psychology of Stated Preferences
EPA Grant Number: R824693Title: Towards a Social Psychology of Stated Preferences
Investigators: Dietz, Thomas
Institution: George Mason University
EPA Project Officer: Chung, Serena
Project Period: October 1, 1995 through December 31, 1999
Project Amount: $180,000
RFA: Valuation and Environmental Policy (1995) RFA Text | Recipients Lists
Research Category: Environmental Justice
Objective:
The problem of valuation is central to environmental policy, but valuation is difficult because many environmental policies have substantial impacts on aspects of the world where social value may not be adequately captured by market prices. Contingent valuation methods (CVM) have been used as an alternative or supplement to market prices as a means of assessing social value. If they work, these methods have the advantage of capturing values that are not captured in market prices. CVM proceeds by asking a representative sample of people what they would be willing to pay to preserve or create some environmental benefit or avoid some environmental cost.
This project had two goals. First, we have linked willingness to pay (WTP), the concept that underpins contingent valuation, to the emerging social psychological literature on environmental concern. This linkage is theoretically important, as it bridges two of the more robust literatures in the environmental social sciences. It also is of practical importance because it advances understanding of the beliefs and values that underpin WTP and those related to conflicts about environmental policy.
Second, we have engaged in the emerging discussion on the use of deliberative processes in environmental policy and conducted an experiment to compare a standard CVM survey with a method of eliciting WTP that involves group deliberation. This experiment provides a test of deliberative theory and may suggest methods for CVM studies that are less prone to some of the methodological weaknesses noted in the literature.
Summary/Accomplishments (Outputs/Outcomes):
Social Psychology and Research Results. Before examining the social psychological determinants of WTP, we conducted an analysis comparing the prevalent theories of environmental concern: the Stern/Dietz values/beliefs theory; the norm activation theory that was initiated by the New Ecological Paradigm (NEP) approach of Schwartz, Dunlap, et al.; and the Acultural@ theory implemented by Dake and Inglehart=s post-materialist theory. Our analysis suggests that a theory that considers values, beliefs, and norms (VBN) provides the best predictions of pro-environmental behavior. It also suggests that environmental concern might best be conceptualized as support for the environmental movement and its goals. Our work indicates that there are at least three dimensions to this support: consumer behavior, political activism, and willingness to sacrifice (WTS) (Stern, et al., 1999). Because gender has been one of the most consistent predictors of environmental concern and substantial literature discusses gender and values, we also have looked in some detail at gender differences in values (Kalof, et al., 1998).
We hypothesized that WTP as expressed in a CVM survey on environmental policy is a subset of the more general concept of WTS. WTS includes WTP money in taxes, contributions, or consumer prices, and also includes the Ahassle@ factor involved in changes in lifestyle and a willingness to reduce the material standard of living for environmental protection, time spent in activities to minimize environmental impact, and other factors. The survey contained two open-ended WTP itemsCone asking about gasoline taxes, the other about preservation of tropical forestsCand three general WTS items. Findings showed that the two WTP items load on the same factor as the three WTS items. The NEP scale, which measures beliefs, predicts both WTP and WTS measures. Income is positively related to WTP, but not to WTS. Traditional values are negatively related to both WTP measures, but not to WTS, while altruism is positively related to WTS, but not to WTP. WTS is a strong predictor of WTP, net of other variables, but values, beliefs, and income retain some effect. This finding suggests that while WTP is closely related to the more generic concept of WTS, respondents are considering other factors when answering WTP questions. Some of these factors (i.e., income and beliefs) are consistent across the content of the WTP question, and other factors are specific to the environmental problem being assessed. (We anticipate submitting a paper based on this work in early January.)
Focus Effects. Previous theoretical work suggested that focus effects may be important in WTP responses. We conducted a survey experiment with two crossed experimental conditions. The first condition used four versions of the kinds of impact information given to the respondent: no impact information, information on the area that might be flooded from sea-level rise, information on estimated heat-related deaths, or information about both. The second condition varied the payment vehicle suggested: taxes, prices, contributions, or no vehicle specified. In previous work, we have found that payment vehicle influences both the stated WTP directly and indirectly through an interaction effect with values and beliefs. We hypothesized that information provided about impacts might have a similar effect; however, none of the treatment effects were significant in our experiment. In response to these results, we altered the design of the experiment to compare conventional CVM with a more discursive method, allowing for more power in that analysis. These results suggest that CVM surveys may be more robust with regard to questioning wording effects than is sometimes suggested.
Conventional Versus Discursive WTP. One of the basic concepts underpinning our project was the idea that people may make more rational decisions after a structured group discussion than when acting in isolation (Dietz and Stern, 1998). Our experiment to examine this hypothesis had two conditions. In one, respondents were mailed a standard CVM survey. The survey described the impacts and possible health effects that a climate-related sea-level rise had on the United States, and described a policy of tree planting to reduce greenhouse gas emissions. Respondents were asked to think about what factors they would take into consideration before answering a WTP question on tree planting. After answering the WTP question, they were asked to list the things they considered and to identify the three most important factors in their decision. In the discursive protocol, small groups met with a group facilitator. The WTP question was posed to the group. Following nominal group protocol, group members were asked to privately write things that should be taken into consideration in answering the question, and then the individual lists were pooled into a group list. After discussion, the participants were asked to privately complete the survey instrument.
Because of the amount of data involved, we have not completed our analysis of this experiment. We are comparing the central tendency and variability of stated WTP between the two modes of elicitation. We also are comparing the survey and group process with regard to the reasons participants say they considered in making their decisions and the influence of those reasons on the stated WTP. Current plans are to submit papers based on this analysis to refereed journals during spring 2000.
Conclusions. Our results to date lend some support to the use of CVM in environmental policy. Although WTP is related to the key variables of the values/beliefs/norm theory of environmental concern, and especially to the WTS dimension of that theory, WTP is not identical to WTS. This is consistent with the notion that respondents are offering expressions of their concerns that take into account other factors such as their income. The negative results from the question-wording experiment also lends support to the use of CVM, in that changes in payment vehicle and in the kinds of impact information provided in a survey had no effect on stated WTP. Our results also suggest that variation in individual WTP is driven substantially by differing beliefs about the sensitivity of the biosphere to human intervention and, to some extent, by differing values regarding environmental change.
Journal Articles on this Report : 3 Displayed | Download in RIS Format
Other project views: | All 4 publications | 3 publications in selected types | All 3 journal articles |
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Dietz T, Stern PC. Science, values, and biodiversity. Bioscience 1998;48(6):441-444. |
R824693 (Final) |
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Dietz T, Kalof L, Stern PC. Gender, values, and environmentalism. Social Science Quarterly 2002;83(1):353-364. |
R824693 (Final) |
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Stern PC, Dietz T, Abel T, Guagnano GA, Kalof L. A value-belief-norm theory of support for social movements: the case of environmentalism. Human Ecology Review 1999;6(2):81-97. |
R824693 (Final) |
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Supplemental Keywords:
nonmarket valuation, sociological, social science, human ecology., RFA, Economic, Social, & Behavioral Science Research Program, Scientific Discipline, decision-making, Economics & Decision Making, Social Science, contingent valuation, social psychology, surveys, social impact analysis, valuation, decision analysis, incentives, preference formation, embedding effects, taxes, psychological attitudes, stated preference, willingness to payProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.