We do not [says Mathews] usually speak of the long latent period of oxidation as a period of teaching, but it is called in chemistry a period of "inductance"; and we do not say that the oil is learning to oxidize itself, and doing it better and better, but we say that it shows the phenomena of autocatalysis; nor do we say that it forgets again in the dark, but that the intermediary, autocatalytic agent has disappeared; but when organisms show the same kind of phenomena we speak of teaching, of latent periods, of stupidity, of good or bad memories. And it is not impossible by any means that the phenomena of memory, shown in greatest perfection by the mammalian cerebrum, may have at the bottom the same basis as this, and the persistence within certain cells of substances of an autocatalytic nature which have remained from a previous stimulation.1

Mathews and Child emphasize on the inorganic level and on a low organic level the chemical aspect of behavior pointed out by Stone and Sturman-Hulbe on a higher animal level. The place of endogenous chemical excitants in human behavior will be referred to in the following chapter. At this point we shall discuss the effect of the experiential stimuli of the social environment in producing in mankind, during the life span, an unconscious fixation of habits or learned stereotyped reactions of a relatively irreversible character.

The fixation of habits on the unconscious, physiological level by repeated exposure to an experience is shown by the experiments of Pavlov2 and his associates in establishing a conditioned reflex in dogs. If, for example, a dog is given food this induces a flow of saliva (a reflex) and if at the same time a bell is sounded, an electric shock applied at any point on the dog’s body, an odor presented to his nose, or any associated stimulus is given, and if this is repeated a number of times, the sound, the odor, or the shock will then produce alone, without the presence of food, the same amount of saliva. This form of reaction to the associated stimulus is called a conditioned reflex.

1Mathews, A.P.n/an/an/an/a, , 76 (London: Baillière, Tindall & Cox; New York: William Wood & Company. By permission).

2 Pavlov, I. P., Conditioned Reflexes.