Perceptual Control Theory as a Framework for Modelling Living Systems


Perceptual Control Theory (PCT; Powers, Clark & McFarland, 1960; Powers, 1973, 2005) is a self-regulatory framework developed from control system engineering. The theory has been widely applied across the social and life sciences (see yet it is not popularly recognised or understood within academic circles. PCT utilises hierarchically organised negative feedback loops that control their input through ongoing change in output. Higher control loops set the reference value (standard) for lower order loops rather than having any direct effect on observable behaviour. The system as a whole learns through trial-and-error reorganisation of the weighted connections between the systems at adjacent levels. Computer models that utilise PCT include arm co-ordination (Powers, 2008), ball catching (Marken, 2001), crowd behaviour (Tucker et al., 1996), goal-directed walking and balance (Kennaway, 1999) and speech production (Moore, 2007). This paper will involve an introduction and explanation of PCT, brief descriptions of existing computer models, and an overview of current research directions using PCT to model reasoning biases in psychosis and mood regulation in bipolar disorder.

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