Psi-theory, developed by Dietrich Dörner at the University of Bamberg, is a systemic psychological theory covering human action regulation, intention selection and emotion. It models the human mind as an information processing agent, controlled by a set of basic physiological, social and cognitive drives. The theory suggests that perceptual and cognitive processing are directed and modulated by these drives, which allow the autonomous establishment and pursuit of goals in an open environment.

Next to the motivational and emotional system, Psi-theory suggests a neuro-symbolic model of representation, which encodes semantic relationships in a hierarchical spreading activation network. The representations are grounded in sensors and actuators, and are acquired by autonomous exploration.

The concepts of Psi-theory may be reduced to a set of basic assumptions. Psi-theory describes a cognitive system as a structure consisting of relationships and dependencies that is designed to maintain a homeostatic balance in the face of a dynamic environment.

Psi-theory suggests hierarchical networks of nodes as a universal mode of representation for declarative, procedural and tacit knowledge. These nodes may encode localist and distributed representations. The activity of the system is modeled using modulated and directional spreading of activation within these networks.

Plans, episodes, situations and objects are described with a semantic network formalism that relies on a fixed number of pre-defined link types, which especially encode causal/sequential ordering, and partonomic hierarchies (the theory specifies four basic link-types). Special nodes (representing neural circuits) control the spread of activation and the forming of temporary or permanent associations and their dissociations.

At any time, the Psi agent possesses a world model (situation image). This is extrapolated into a branching expectation horizon (consisting of anticipated developments and active plans). In addition, the working memory also contains a hypothetical world model that is used for comparisons during recognition, and for planning.

The situation image is gradually transferred into an episodic memory (protocol). By selective decay and reinforcement, portions of this long-term memory provide automated behavioral routines, and elements for plans (procedural memory).

The atoms of plans and behavior sequences are triplets of a (partial, hierarchical) situation description, forming a condition, an operator (a hierarchical action description) and an expected outcome of the operation as another (partial, hierarchical) situation description. Object descriptions (mainly declarative) are also part of long-term memory and the product of perceptual processes and affordances. Situations and operators in long-term memory may be associated with motivational relevance, which is instrumental in retrieval and reinforcement. Operations on memory content are subject to emotional modulation.