4O Animal Intelligence 



hours is specified by i hr., 2 hrs., etc. In many cases the 

 animal failed in some trial to perform the act in ten or 

 fifteen minutes and was then taken out by me. Such fail- 

 ures are denoted by a break in the curve either at its start 

 or along its course. In some cases there are short curves 

 after the main ones. These, as shown by the figures be- 

 neath, represent the animal's mastery of the association 

 after a very long interval of time, and may be called memory- 

 curves. A discussion of them will come in the last part of 

 the chapter. 



The time-curve is obviously a fair representation of the 

 progress of the formation of the association, for the two 

 essential factors in the latter are the disappearance of all 

 activity save the particular sort which brings success with 

 it, and perfection of that particular sort of act so that it is 

 done precisely and at will. Of these the second is, on deeper 

 analysis, found to be a part of the first; any clawing at a 

 loop except the particular claw which depresses it is theoreti- 

 cally a useless activity. If we stick to the looser phraseology, 

 however, no harm will be done. The combination of these 

 two factors is inversely proportional to the time taken, 

 provided the animal surely wants to get out at once. This 

 was rendered almost certain by the degree of hunger. 

 Theoretically a perfect association is formed when both 

 factors are perfect, - - when the animal, for example, does 

 nothing but claw at the loop, and claws at it in the most 

 useful way for the purpose. In some cases (e.g. 2 in K on 

 P a g e 53) neither factor ever gets perfected in a great many 

 trials. In some cases the first factor does but the second 

 does not, and the cat goes at the thing not always in the 

 desirable way. In all cases there is a fraction of the time 

 which represents getting oneself together after being 

 dropped in the box, and realizing where one is. But for 



