The PSI theory is an exact mathematical model that simulates aspects of human behavior in complex situations. The model offers an explanation of human feelings of anger or helplessness. It models the regulation of motivations explaining why humans choose to pursue one goal over another; it explains personality traits such as extroverted or introverted behavior. The theory implements the co-ordination of cognition, emotion and motivation that underlie all human activity in a neural based “agent” called PSI.
PSI lives on an island, where he looks for and collects Nucleotides (useful material for society at large) while maintaining its personal needs of water and fuel. Water is obtained from lakes, rivers or puddles, while fuel is obtained from oil that is expressed from flowers or hazelnuts. While seeking supplies, it is also exposed to certain dangers that it can feel as pain. These dangers can materialize in the form of falling rocks or sulfur gas that can damage its structure.
PSI is able to learn through experience and experimentation. Not only does it learn about danger but it will also learn how and where to obtain food. This obtained knowledge will help it to plan activities. In addition to the motivation to fulfill basic needs such as hunger and thirst and avoiding pain, PSI also has other needs. He desires to maximize the predictability of its environment and become competent at handling situations.
Depending on the degree of neediness, as well as competence and predictability its emotions are set at different levels. A highly competent PSI living in a predictable world may well be aggressive and exploratory, while an incompetent PSI will exhibit fear. As the emotions, the resolution level of PSI is set by competence predictability and degrees of needs. A fine resolution level determines the speed versus the level of accuracy with which PSI acts based on its perception of the environment.
Given the described construct, PSI has the mechanism to determine its goals. Next it needs to act to achieve the selected goal. Actions are determined based on a plan that is either in memory or constructed. For both purposes, PSI has been equipped with a short-term (protocol) and a long-term memory. A "protocol memory" is a kind of log for its ongoing internal and external activities. Long-term memory preserves history of activity and serves the learning process. By memorizing for example the construction of a typical plan, PSI is able to identify the principles or heuristics that it has used when planning.
With the described abilities, a PSI is able to live in a particular habitat where it can learn to explore and survive by satisfying its internal (for example hunger, thirst) and external (for example nucleotides, gold, or oil) needs. It can learn, plan and act in co-dependence with his emotional state.