The acquisition of new modes of response. Expressed in less technical language this means simply that human beings can learn by experience, and that they tend to repeat actions they have once learned. Where an animal is perfectly adjusted to its environment, all stimuli issue in immediate and nicely adjusted responses. This happens only where the environment is very simple and stable, and where in consequence no complexity of structure or action is necessary. In the clam and the oyster, and in some of the lower vertebrates, perhaps, instinctive activity is almost exclusively present. But in the case of man, so complicated are the situations to which he is exposed that random instinctive responses will not solve his problems. He must, as with his highly modifiable nervous system he can, acquire new modes of response which will, in the complexity of new situations serve as effectively as his original tendencies to act would serve him in a simpler and stabler environment. A human being in a modern city cannot live by instinct alone; he must acquire an enormous number of habits to meet the variety of complex situations he meets in daily life. A monkey exists with fairly fixed native tendencies to act. But civilization could never have developed if in man new ways could not be acquired to meet new situations, and if these new ways could not be retained and made habitual in the individual and the race.
Trial and error and deliberate learning. Whenever, as happens a large number of times daily in the life of the average man, old ways of response, inborn or formerly acquired, are inadequate to meet a new situation, there are two methods of acquiring a new and more adequate response. One is the method of trial and error, already discussed, whereby animals and humans try every possible instinctive response to a situation until one brings satisfaction and is retained as a habitual reaction when that situation recurs. The other is a delay in response, during which delay reflection, a consideration of possible alternatives, and a conscious decision, take place. The technique of this latter process will be discussed more specifically in the next chapter.
Whether acquired by trial and error, or through reflection, learned acts are, the first time they are performed, frequently imperfect, only partly effective, and performed with some difficulty. With successive repetitions their performance becomes more rapid, more immediate, and more adjusted to the specific situation to be met. And as they become more familiar responses to familiar stimuli they cease to be conscious at all. They are performed with almost as little difficulty or attention as normal breathing.
Some conditions of habit-formation. The acquisition of habits is so important in the education of human beings that the conditions under which they can be acquired and made permanently effective have been closely studied. From experiments certain fundamental conclusions stand out. A habit is acquired by repetition, and the "curves of learning" show certain recurrent features. In the first few repetitions of an acquired activity, there is progress in the rapidity, effectiveness, and accuracy with which the response is made. There is, up to a certain point, an almost vertical rise in the learning curve. After varying numbers of repetitions, depending somewhat on the particular individual, there occur what are known as "plateaux," during which no progress in speed or accuracy of response is to be observed. In experiments with the learning of typewriting, for example, it has been found that the beginner makes rapid progress up to the point, say, where he can write fifty words a minute without error; there is a long interval not infrequently before he can raise his efficiency to the point of writing seventy words a minute correctly. Analogous conditions have been observed in the speed with which the sending and receiving of telegraphic messages is learned. These "plateaux" of learning are sometimes to be accounted for by muscular fatigue. Frequently there is actual progress in learning during these apparent intervals of marking time. Some of the less observable features of skill in performance which only later become overt in speed and accuracy are being attained during these seemingly profitless and discouraging intervals. Not infrequently in the acquisition of skill in the playing of tennis or the piano, or in the solution of mathematical problems, a decided gain in skill and speed comes after what seems to be not only lack of progress but decided backsliding.[1] It is this which led William James to quote with approval the aphorism that one learns to skate in summer and swim in winter.
Drill versus attentive repetition in learning. The rapidity with which habits may be acquired and the permanency with which they may be retained depend on other factors than simply that of repetition. Mere mechanical drill is effective in the acquisition of simple mechanical habits. The most attentive appreciation of the proper things to be done in playing tennis or the piano will not by itself make one an expert in those activities. The effective responses must actually be performed in order that the appropriate connections within the nervous system may be made, and may become habitual. A habit is physiologically nothing but a certain set or direction given to paths in the nervous system. These paths become fixed, embedded, and ingrained only when nerve currents pass over them time and time again.
[Footnote 1: See Ladd and Woodworth: Physiological Psychology, pp. 542-92.]
Mere repetition, on the other hand, will not suffice in the acquisition of complex habits of action. The learning of these requires a deliberate noting and appreciation of the significant factors in the performance of an activity, and the consciously chosen repetition of these in succeeding instances until the habit is well fixed. One reason why animals cannot be taught so wide a variety of complex habits as can the human being is that they cannot keep their attention fixed on successive repetitions, and that in learning they literally do not know what they are doing. They cannot, as can humans, break up the activity which they are in process of learning into its significant factors, and attend to these in successive repetitions. The superiority of deliberate learning over the brute method of trial and error consists precisely in that the deliberate and attentive learner can pick out the important steps of any process, and learn rapidly to eliminate random and useless features of his early performances without waiting to have the right way "knocked into him" by experience. He will short-circuit the process of learning by choosing appropriate responses in advance, noting how they may be made more effective and discovering methods for making them so, and for eliminating useless, random, and ineffective acts. What we call the "capacity to learn" is evident in marked degree where there is alert attention to the steps of the process in successive repetitions. The truth in the assertion that an intelligent man will shortly outclass the merely automatically skillful in any occupation or profession requiring training, lies not in any mysterious faculty, but in the peculiarly valuable habit of attending with discriminating interest to any process, and learning it thereby with vastly more economical rapidity. Genius may be more than what one writer described it, "a painstaking attention to detail"; but a painstaking attention to the meaning and bearing of details it most decidedly is.
Learning affected by age, fatigue, and health. There are certain conditions not altogether within the control of the individual which affect the rapidity with which habits are acquired. One of the most important of these is fatigue. Connections among the fibers that go to make up the nervous system cannot be made with ease and rapidity when the organism is fatigued. At such times there seems to be an unusually high resistance at the synapses or nerve junctions (where there is a lowering of resistance to the passage of a nerve current when habits are easily formed). After a certain point of fatigue, whether in the acquisition of motor habits or the memorizing of information, in which the process is much the same, the rate of learning is much slower and the degree of accuracy much less. The length of time through which habits are retained when acquired during a state of fatigue is also much less than under a more healthy and resilient condition of the organism.
The point of fatigue varies among different individuals and in consequence the conditions of habit-formation vary. But some conditions remain constant. For instance, in experiments with memory tests (memory being a form of habit in the nervous system), material memorized in the morning seems to be most rapidly acquired and most permanently retained.
The age and health of the individual also are important factors in the capacity to learn, or habit-formation. Conditions during disease are similar to those obtaining during fatigue, only to a more acute degree. The toxins and poisons in the nervous system at such times operate to prevent the formation of new habits and the breaking of old ones. For while the synapses (nerve junctions) may offer high resistance to the passage of a new stimulus, they will lend themselves more and more readily to the passage of stimuli by which they have already been traversed.