p: a particular strength of skinner's research was his reliance on the experimental method, used controlled conditions to discover a possible causal relationship between variables
E: skinner's reliance on the skinner box was a good example of this approach in practice. by manipulating the consequences of behaviour, he was able to accurately measure the effects on the rat's behaviour
L: this allowed to establish a cause and effect relationship between the consequences of a behaviour and the frequency of its occurrence