higher animals exhibit the law of transfer of response, _i.e._ when two stimuli have often been applied together, one will ultimately call out the response which formerly the other called out. This law is one of the chief bases of habit. It is also obviously essential to our understanding of language: the sight of a dog calls up the word “dog”, and the word “dog” calls up some of the responses appropriate to a real dog. There is, however, another element in learning, besides mere habit. This is the element dealt with by Thorndike’s “Law of Effect.” Animals tend to repeat acts which have pleasant consequences, and to avoid such as have unpleasant consequences. But, as we saw a moment ago, “pleasant” and “unpleasant” are words which we cannot verify by objective observation. What we can verify by observation is that an animal seeks situations which in fact have had certain results, and avoids situations which in fact have had certain other results. Moreover, broadly speaking, the animal seeks results which tend to survival of itself or its offspring, and avoids results which tend in the opposite direction. This, however, is not invariable. Moths seek flames and men seek drink, though neither is biologically useful. It is only approximately, in situations long common, that animals are so adjusted to their environment as to act in a way which is advantageous from a biological standpoint. In fact, biological utility must never be employed as an explanation, but only noticed as a frequent characteristic, of the ways in which animals behave. Dr. Watson is of the opinion that Thorndike’s “Law of Effect” is unnecessary. He first suggests that only two factors are called for in the explanation of habit, namely, _frequency_ and _recency_. Frequency is covered by Thorndike’s “Law of Exercise”, but recency, which is almost certainly a genuine factor, is not covered by Thorndike’s two laws. That is to say, when a number of random movements have finally resulted in success, the more recent of these movements are likely to be repeated earlier, on a second trial, than the earlier ones. But Dr. Watson finally abandons this method of dealing with habit-formation in favour of the one law of “conditioned reflexes” or “learned reactions”. He says (_Behaviorism_, p. 166):