白鼠の暫有的習慣の固定並に其に到る經過に就て

抄録

It has been proved experimentally by such investigators as De Camp, Tolman, Kuo, Clements and Anderson that when we make white rats choose between both paths in the maze, one of which is spatially or temporarily shorter than the other, they learn to prefer the shorter alley within certain limits of the experimental conditions. Now, that the animal preferred one path to the other is admitted by its beginning to take uniformal runs to the one path which is more advantageous, while up to then it had been running to either path irregularly. Those serial runs to the one side assume a habitual nature and tend to mechanize at last if they are continued. Before they shall have a mechanical turn, if we make them discontinue only with such small numerical repetitions as nine times or ten, then the animal has for some time a raw or transient habit to go to the side which has been adapted to. After the lapse of a definite length of time, the same animal can remake such a momentary habit, this time to the other path, under the reversed condition.
These two experiments, one of the right path adaptation and the other of the left, made under the same essential condition, compose one experimental set and if several sets of this sort under the different teaction conditions are repeated one after another with the same animals at the given interval, in a certain occasion of a later set of the experiment the transient habit of each animal which has been formed directly before comes to stabilize to the path and now each animal will no more respond to the experimental condition, as if a pendulum which had been swinging somewhat asymmetrically to right and left were attracted to any one side with declining oscillations and came to standstill.
Now, in case each animal assumes a transient habit as the result of the trialand-error runs, it displays some differences of adaptive easiness between on the right path and on the left, notwithstanding that the essential condition of reaction remains the same on either side. In most animals, those apparent handedness tendencies manifesting themselves on early occasion continue in the constant relation to the end through the experiments of several sets, although in some animals they become reversed, or in others ambiguous in the course. Therefore, in these connections, some types of stabilization can be sought after.
To this experiment, subject animals had been attended to with regard to learning ability, disposition, sex, any test-experience and especially, age. Consequently, animals of either sex, four to six months old only had been chosen, because such ones can form adaptive habits to any one side path, in these repeated experiments, better and easier than the younger; each animal singled out ran to either food-box in the maze 8 times, or in one case 10 a day; two consecutive days of experiment, one off-day was given according to the Katz's experimental researches; the interval between experiments was restricted to ten days.
The research was made with three kinds of experiment, one of which consisted in preferring the temporarily shorter path to the longer, the second the less obstructive path to the more and the third the spatially shorter to the longer. In the first experiment an U-shaped maze was used, each path of which was 150 centimetre long to either food-box from the entrance; while the ratio of the detention time length in one path to that in the other, in two classes, was decreased per experimental set, as 0.5':7.5' to 1':7.5', then to 2':7.5' etc., in the other it was increased, as 4':7.5' to 3':7.5', then to 2':7.5' and so on. In the second experiment, the ratio of the quantity of obstacles to be got over in one path to that in the other of the U-shaped maze was enlarged one set after another, as 2:3 to 2:4, or 2:7.5 to 2:8 and so on.