Once formed, the connections by which, when an animal feels a certain sense-impression, he does a certain thing, persist over considerable intervals of time. With the curves on pages 39 to 58 and 60 to 65 are given in many instances[17] additional curves showing the animal’s proficiency after an interval without experience. To these data may be added the following:—
The three chicks that had learned to escape through the long labyrinth (involving twenty-three associations) succeeded in repeating the performance after ten days’ interval. Similarly the chicks used as imitators in V, W, X and Y did not fail to perform the proper act after an interval of twenty days. Cat 6, who had had about a hundred experiences in C (button), had the association as perfect after twenty days as when it left off. Cat 2, who had had 36 experiences with C and had attained a constant time of 8 seconds, escaped fourteen days later in 3, 9 and 8 seconds, respectively, in three trials. Cat 1, after an interval of twenty days, failed in 10 minutes to escape from C. The signal for climbing up the front of the cage was reacted to by No. 3 after an interval of twenty-four days. No. 10, who had learned to discriminate between ‘I must feed those cats’ and ‘I will not feed them,’ was tried after _eighty_ days. It was given 50 trials with the second signal mingled indiscriminately with 25 trials with the first. I give the full record of these, ‘yes’ equalling a trial in which she ‘forgot’ and climbed up, ‘no’ equalling a trial in which she wisely stayed down. Dashes represent intervening trials with the first signal, _to which she always reacted_. It will be observed that 50 trials put the cat in the same position that 350 had done in her first experience, although in that first experience she had had only about a hundred trials after the association had been perfected. The association between the first signal and climbing up was perfect after the eighty days.
