Topographic analysis of the rat's bar behaviour in the Skinner box

We analysed precisely, with video tapes, the behaviour of 38 Wistar rats submitted to a continuous reinforcement in a Skinner box. Animals displayed 14 different behavioural patterns close to the bar. We found that the increasing frequency of the bar press, generally considered as a unitary response was, in fact, due to summation of the development of several different behaviour frequencies. A CAH analysis led to the distinction of 5 behavioural categories. The frequency of each category of behavioural patterns varied throughout learning in respect with the number of sessions before criterion. So, learning in the Skinner box would result from an association of the reinforcers with the successive units of behaviour exhibited by animals at the bar whose sequential organization and nature change according to acquisition rapidity.