32 L. W. SACKETT 



When No. 4 was given all these locking devices in combina- 

 tion series there was hopeless confusion during the first feeding 

 period. The chief difficulty was that he neglected the lever. 

 He had reverted to the lever position so many times during his 

 troubles with new parts that he had broken this association. 

 He succeeded in opening the box 14 times but still had no grasp 

 upon the problem. The next day, as he did not begin with his 

 customary vigor, the plug and hook were removed and the 

 button turned vertical leaving him only the lever for 20 trials. 

 He soon re-mastered the lever, eliminating habitual associations 

 with other devices. When the plug was added there was another 

 long, hard struggle to learn the two in order. The button and 

 the hook were next added simultaneously and were soon mas- 

 tered. Then followed a long series in which the box was opened 

 successfully in much the same way each time. After pushing 

 the lever down he would stretch up over the corner of the box 

 and pull the plug. Then without getting down he would edge 

 over and downward, following almost a direct line with his 

 head from the plug to the button and hook. The time for the 

 combination varied from seven to ten seconds. 



Porcupine No. 11 was given this puzzle-box as his first prob- 

 lem after being captured. The number of tests was limited so 

 that they could be tabulated. The records for each device 

 represent the work of a single day, but the whole represents a 

 little more than one week. No. 11 was allowed to open the 

 box 40 times when 20 were not sufficient to fix the co-ordination 

 on the muscular side in attaining dexterity ; though it was often 

 associated on the mental side much sooner. This, it will be 

 observed in table V, was necessary in the case of the lever, 

 button, lever-plug combination and in the whole combination. 



Every experimenter appreciates how inadequately time by a 

 stop-watch tells the story of the animal's behavior but the 

 well established custom of presenting results in this one unit 

 of measure has been followed. Table V needs no detailed 

 interpretation. 



The large numbers in the series of time records for the com- 

 bination deserve a word of explanation as they indicate much 

 more than really exists. It was the habit of No. 11 to open 

 the button and the hook by reaching down from the top after 

 he had mounted the box, in a manner similar to that of Davis' 



