A very definite answer to this question is furnished by observation of the behavior of the dancers in the tests. Most of them continuously made use of their eyes, their noses, and their vibrissae. Some individuals used one form of receptive organ almost exclusively. I frequently noticed that those individuals which touched and smelled of the labyrinth passages most carefully gave least evidence of the use of sight. It is safe to say, then, that under ordinary conditions habit formation in the dancer is conditioned by the use of sight, touch, and smell, but that these senses are of extremely different degrees of importance in different individuals. And further, that, although in the case of some individuals the loss of sight would not noticeably delay habit formation, in the case of others it would seriously interfere with the process. When deprived of one sense, the dancer depends upon its remaining channels of communication with environment. Indeed there are many reasons for inferring that if deprived of sight, touch, and smell it would still be able to learn a labyrinth path; and there are reasonable grounds for the belief that a habit once formed can be executed in the absence of all special sense data. Apparently the various receptive organs of the body furnish the dancer with impressions which serve as guides to action and facilitate habit formation, although they are not necessary for habit performance.
The reader may wonder why I have not carried out systematic experiments to determine accurately and quantitatively the part which each sense plays in the formation of a labyrinth habit instead of basing my inferences upon incidental observation of the behavior of the dancers. The reason is simply this: the number and variety of experiments which were suggested by the several directions in which this investigation developed rendered the performance of all of them impossible. I have chosen to devote my time to other lines of experimentation because a very thorough study of the conditions of habit formation has recently been made by Doctor Watson.[1]
[Footnote 1: Watson, J. B., Psychological Review, Monograph Supplement,
Vol. 8, No. 2, 1907.]
What is the role of sight in the dancing mouse? How shall we answer the question? The evidence which has been obtained in the course of my study of the animal indicates that brightness vision is fairly acute, that color vision is poor, that although form is not clearly perceived, movement is readily perceived. My observations under natural conditions justify the conclusion that sight is not of very great importance in the daily life of the dancer, and my observations under experimental conditions strongly suggest the further conclusion that movement and changes in brightness are the only visual conditions which to any considerable extent control the activity of the animal.
CHAPTER XII
EDUCABILITY: METHODS OF LEARNING
Nearly all of the experiments described in earlier chapters have revealed facts concerning the educability of the dancer. In order to supplement the knowledge of this subject thus incidentally gained and to discover the principles of educability, the specially devised experiments whose results appear in this and succeeding chapters were arranged and carried out with a large number of mice. In the work on the modifiability of behavior I have attempted to determine (1) by what methods the dancer is capable of profiting by experience, (2) the degree of rapidity of learning, (3) the permanency of changes wrought in behavior, (4) the effect of one kind of training upon others, (5) the relation of re-training to training, and (6) the relation of all these matters to age, sex, and individuality.
As it is obvious that knowledge of these subjects is a necessary condition for the intelligent appreciation of the capacities of an animal, as well as of the choice of methods by which it may be trained advantageously, perhaps it is not too much to expect that this investigation of the nature and conditions of educability in the dancing mouse may give us some new insight into the significance of certain aspects of human education and may serve to suggest ways in which we may measure and increase the efficiency of our educational methods.
Merely for the sake of convenience of description I shall classify the methods which have been employed as problem methods, labyrinth methods, and discrimination methods. That these names are not wholly appropriate is suggested by the fact that discrimination necessarily occurs in connection with each of them. As problem methods we may designate those tests of initiative and modifiability which involve the opening of doors by pushing or pulling them, and the climbing of an inclined ladder. An example of the labyrinth method has been presented in Chapter XI. The name discrimination method I have applied to those tests which involve the choice of one of two visual, tactual, or olfactory conditions. The white-black discrimination tests, for example, served to reveal the rapidity and permanency of learning as well as the presence of brightness vision.
In the case of most mammals whose educability has been studied experimentally, problem methods have proved to be excellent tests of docility and initiative. The cat, the raccoon, the monkey, in their attempts to obtain food, learn to pull strings, turn buttons, press latches, slide bolts, pull plugs, step on levers. The dancer does none of these things readily. Are we therefore to infer that it is less intelligent, that it is less docile, than the cat, the raccoon, or the monkey? Not necessarily, for it is possible that these methods do not suit the capacity of the animal. As a matter of fact, all of the tests which are now to be described in their relation to the educability of the dancer bear witness to the importance of the selection of methods in the light of the motor equipment and the habits of the animal which is to be tested. Judged by ordinary standards, on the basis of results which it yields in problem and labyrinth tests, the dancer is extremely stupid. But that this conclusion is not justified is apparent when it is judged in the light of tests which are especially adapted to its peculiarities.