capacities, such as learning, from the particulars of performance, and begins by modelling performance in a given species and environment. The resultant model is then used to frame an understanding of the focal construct in a specific context. Disequilibrium theory Timberlake’s disequilibrium approach to reinforcement (also known as: behaviour regulation theory, response deprivation theory, molar equilibrium theory, and disequilibrium theory) resituates the locus of behaviour change from a response strengthening power of particular environmental stimuli envisioned in mainstream views, like food, to constrained activities, like eating. Reinforcement is attributed to the animal’s correcting deficits in relative activity rates. Further reading Behaviour Systems Theory Timberlake, W. (1983). The functional organization of appetitive behavior: Behavior systems and learning. In M. Zeiler & P. Harzem (Eds.), Advances in Analysis of Behaviour, Vol. 3, London: John Wiley & Sons, pp. 177–221. Timberlake, W. (1990). Natural learning in laboratory paradigms. In D.A. Dewsbury (Ed.), Contemporary issues in comparative psychology (pp. 31–54). Sunderland, MA: Sinauer Associates. Disequilibrium Theory References Ethologists 20th-century American psychologists 1942 births 2019 deaths