x SOME EXPERIMENTAL RESULTS 223 



discrimination test. An animal is accustomed to react to 

 a particular object, and by so doing gets food. We wish 

 to decide whether the reaction is determined by the sight 

 of the object, or the desire for the food. Let us then 

 multiply the object by two or three, and arrange so that 

 the food is connected with one only. If the animal has 

 means of knowing this, and the food of course being out 

 of sight at the time of action prefers the appropriate 

 object, the motive seems sufficiently clear. I have already 

 mentioned some of the experiments which I made in this 

 connection. The behaviour of the cats to the drawers 

 showed in two cases a decided, in the third case a slighter, 

 preference for the right one. The otter showed no hesi- 

 tation or confusion at all between the two similar boxes, in 

 one of which the catch had to be lifted, and in the other, 

 depressed. But as a special test of this question, I made 

 some experiments with Jack and his strings. 



In the first series, 1 I put a paper on the projection over a door, 

 carried the string over a neighbouring picture, and dangled a 

 dummy string down from the upper hinge of the door, so that the 

 two strings hung at an interval of about a yard. The dummy was 

 the nearest to Jack. As I was arranging this, Jack tugged at the 

 wrong string, and I drove him away. When I put the biscuit 

 up, and called him, he ran up, and pulled the right string. Next 

 time he pulled the wrong string. 



His whole series is as follows. 



1. Right string first. 



2. Wrong first. 



3. Right first (seeing me put it up). 



4. Right first (seeing put up). 



5. Wrong first ; not seeing put up. 



6. Right first; ditto. 



7. Right approached, not pulled ; pulled wrong, then right 

 (ditto). 



8. Right first. 



9. Right first. 



10. String shortened (to obviate difficulty of his seizing it too 



1 I had previously made an experiment with four strings attached to 

 his box. Three were dummies, and one pulled the lever which opened 

 the box. Jack virtually failed in this. I kept turning the box about, and 

 his tendency was to take the string nearest him. He was right first 

 seven times out of twenty. The strings swung about near together, and 

 this and the movement of the box made matters too puzzling for him. 



