This thesis develops a framework for making ecologically sustainable decisions. It is an integrative thesis that draws its data from the fundamental concepts underlying the disciplines of psyschology, linguistics and biology. Its orientation is essentially theoretical, but its application is practical. It is presented in three parts. Part 1 sets out the theoretical context and proposes a basis for understanding decision-making processes in an interactive, evolutionary context. This part focuses particularly on subjective factors that play a role when an organism is in the process of making a decision. Part 1 provides an underpinning for the core of the thesis. Part 2 forms this core. It considers the context in which decisions are made and overviews current decision-making frameworks that aim at ecologically sustainable outcomes. It proposes a process of metabolic mapping of materials and energy flows across integrated socio-political bioregions as a basis for decision-making. Part 3 considers the implications of the approach in terms of its utility, reliability and validity. This part also looks at the role of ethics in decision-making and outlines the strengths and weaknesses of the new approach. The principle rinding is that research and decision-making are fundamentally distinct, often confused concepts. An integrative approach to decision-making is required to counter the increasing fragmentation in research and professional and administrative specialisation. A research tool that bridges the plethora of theoretical orientations is proposed. This involves the use of a semantic metalanguage to capture meaning in a rigorous and verifiable way. Such a metalanguage gives us a means of understanding the subjective experience of organisms, and in particular, their subjective perception of reality which guides their decision-making. A second finding is that, unlike research, which necessarily involves a process of context reduction, sound decision-making necessarily involves a process of context augmentation. And finally it proposes a method of metabolic mapping on a bioregional basis operating under the principle of subsidiarity as the most appropriate route towards sustainable decision-making.