522 



POPULAR SCIENCE MONTHLY. 



A record of the route in connection with the time of the trip is 

 necessary as an index of the effect of experience, because if the 

 animal takes a direct course, with no wrong turns, but makes sev- 

 eral halts, the time may indicate no profiting by the former acts, 

 whereas the route will at once show that there has been improvement. 

 Thus one record supplements the other. 



These experiments were made six or eight times a day 

 until fifty trials had been given. The tenth trip was made in 

 three minutes five seconds, with two mistakes in turning. The 

 time of the twentieth journey was but forty-five seconds, and that 

 of the thirtieth, forty seconds. In the latter experiment a direct 

 course was taken; this was also true in the case of the fiftieth trip, 

 which was made in thirty-five seconds. Fig. 3 represents graphically 

 the times of the first twenty experiments of this series. The vertical 



40 



?s 



32 

 28 

 24 

 2£ 

 16 

 12 

 8 

 4 



-1_J_L 



1 Z 34 5 67 8 9 10 11 \Z 13 14 15 16 17 18 1920 



Pig. 3. Times of Experiments from One to 

 Twenty. 



V 



NEST 



Fig. 4. Plan of Labyrinth No. 2. 



column of figures at the left, 1 to 40, indicates minutes; the horizontal 

 line of figures, 1 to 20, gives the number of trials. 



That the turtle profited by experience, and that very rapidly, is 

 evident from the figures. The average time for the first ten trips, from 

 one to ten, was eight minutes fifty-four and a half seconds; the average 

 time of the ten trips between thirty and forty was one minute three 

 seconds. What at first took minutes, after a few trials required only as 

 many seconds. There was remarkably little aimless wandering, crawling 

 up the sides of the box and sulking in the corners after the third experi- 

 ment. In fact, the animal soon began to behave as if it had the goal in 

 mind and was intent on making directly for it. It learned with sur- 

 prising quickness to make the proper turns and to take the shortest 

 path. Three or four times I noticed it turn in the wrong direction, 

 crawl into a corner and, as it seemed, become confused, for it then re- 



