Human consumption of products and services is a major factor in the process of global change. So far, integrated assessment models (e.g., TARGETS) implicitly incorporate the behaviour of consumers. This report assembles several behavioural theories in a generic behaviour model. To guide the development of a behaviour simulation programme. This computerised tool will serve to enhance and validate the future projections generated by integrated assessment models, and offer decision-makers points of application in setting priorities and developing effective (behavioural) strategies for sustainable development.