Engineers make continuous effort to improve the sustainability of products, such as using sophisticated manufacturing approaches, conducting rigorous sustainability analysis, and including materials that decrease environmental impact. However, thoughtful sustainability efforts are sometimes hidden from customers, which are wasted sales features if customers do not know or value them. As green marketing messages are not always trusted, another approach is to communicate sustainability to the customer through the product's visible features. This research proposes and tests a newly-created design technique that helps product designers communicate sustainability in the products they design and, in turn, helps customers to think about sustainability during purchase decisions. Three empirical studies, with designers and potential customers as subjects, are conducted.

Study 1 in Chapter 3 proposes and tests a new design technique that uses psychological priming to help designers generate product features that communicate sustainability to the customer, termed as sustainability-triggering, or ST features. Priming is a psychological experimental technique that uses an artifact, exposure, or experience to stimulate cognitive accessibility of specific mental content. Here, priming is used prior to a design task. The author investigates primes of sensory-and-sustainability-heightening activities, and compares these to existing primes and a control condition. The test primes are proven to be comparatively more effective in helping designers generate product features that communicate sustainability, as judged by both experts and customers.

Study 2 in Chapter 4 and Study 3 in Chapter 5 investigate customer evaluation of sustainable products. A selection of ST features generated from the priming-designer experiment were built into realistic plastic prototypes. Subjects participated in test versus control purchase experiments, in which some "customers" saw a subset of products with ST features during purchasing tasks and some did not. Study 2 demonstrates that exposure to ST features significantly increases thoughts of purchase criteria possibly or definitely related to sustainability. Study 3 investigates the purchase-related decisions with exposure to ST features. Analyzed at an aggregate level, subjects were more likely to choose the more sustainable product, though it was only significant at the p<0.1 level; and the presence of ST features significantly increased importance of sustainability in making purchase decisions, and motivated them to seek additional information on sustainability and devote more attention to it. Disaggregated results reveal that the ST features had a more significant influence on some choices than others.

To decrease the environmental footprint of a product to the greatest extent possible, it is necessary to help people change their product purchase and usage habits: a sustainable product that is not purchased does not help the environment. It is hoped that this research will facilitate the design of sustainable products that increase purchases and decrease environmental impact.