Laurie Taylor commits the common error of confusing a theory and a model. Behaviourism is not a theory, but it is a model. The difference is that a theory is universal, while a model is valid only within defined limits. Hence, while at times we may act like angels, at others we act like rats. Within those latter limits, behaviourism is a good model.
Lewis Elton, Visiting professor, University College London and the universities of Gloucestershire and Surrey.