Bias in judgments of the environmental impact of green consumption: Illuminating heuristic processes and boundary conditions

Abstract

As the transition to sustainable consumption has received attention as a means to achieve Sustainable Development Goals, the “green” consumption market and consumers’ interests in purchasing environmentally friendly products are growing rapidly. However, although a product’s eco-friendly claims may credibly signal low-ecological impacts, compared to conventional products, relying on such claims may obscure the fact that environmental impacts also depend on consumption quantity. This dissertation examines how consumption quantity influences individuals’ environmental impact judgments and whether its influence varies by product type (green vs. conventional), building on environmental psychology, environmental communication, and decision research. Chapter 3 reports on the evidence of quantity insensitivity effect in green consumption: whereas an additional conventional vehicle increased participants’ judgments about a family’s environmental impact, an additional hybrid vehicle did not. Chapter 4 documents the attempts to reproduce the quantity insensitivity effect under varying experimental conditions (e.g., provision of accurate impact information, improvement of data quality, adjustment of manipulation strengths) and provides a more comprehensive perspective of the evidence through an internal meta-analysis. Chapter 5 examines the effect of participants’ perceptions of the family’s likelihood of engaging in green behavior on their judgments about the family’s environmental impact. A moderated mediation model reports that higher consumption quantity resulted in the lower perceived likelihood of engaging in green behavior, and in turn, greater environmental impact judgments, but only in the case of conventional vehicles. In the case of hybrid vehicles, the results suggest that participants viewed the consumer (Baker family) as being more likely to perform green behaviors, regardless of consumption quantity, and thus keeping their judgments about the family’s environmental impact equally low. This chapter also elaborates on how and when these effects are likely to occur, focusing on the moderating roles of individual differences in impact attribution patterns and ecological values. Overall, findings from the dissertation highlight the critical yet frequently neglected perspectives on consumption quantity associated with ever-growing green consumerism and provide implications for research on consumer judgment and decision-making in the domain of ecological consumption.