[4][5] In the early 1950s, B. F. Skinner and others began to point out the similarities between the learning process and evolution through variation and selection.
[6][7][8] More recently, models explicitly analogous to gene mutation and selection by reinforcement have been applied to operant conditioning phenomena.
[13] On the other hand, Zener, Liddell and others[14][15] argue that the variation in behaviors that psychological reinforcement acts on is not random.
The ethologist Lorenz first identified the dog’s behavior as a particular instinctive pattern, similar to a repertoire.
The observed repertoire in a particular animal depends on the reward size and nature of the stimulus: anticipation of food will lead to a different repertoire than anticipation of electric shock.