170 OTTO C. GLASER 



hardly adequate to measure real differences in the ability to learn. 

 The individuals which are thrown out of commission, by the very 

 nature of the problem itself, are simply out of the running; they 

 are unable to compete, and their failure is no more to be ascribed 

 to inferior intelligence than the failure of a blacksmith to win 

 prizes at a swimming meet is to be ascribed to the superior 

 strength of the other contestants. 



Objectively, of course, the facts are that some animals fail, 

 whereas others succeed. Success may come with progressive 

 reduction in the complexity of the path, and in the time taken to 

 traverse it, or with either of these elements separately; failure 

 may result from the corresponding opposites. We can say with 

 justice that the capacity to learn also expresses itself in one or 

 more of these ways, but the obvious inference would not be the 

 correct one. Should the chain of activities that we are interested 

 in be inaugurated, our objective measurements would give us the 

 information we want, but when some other chain is set up, the 

 measurements show simply the extent to which the second dis- 

 turbs the first chain. In other words, if the problems convert the 

 animal into a non-learning mechanism, the movements which the 

 individual performs throw no light on its learning capacity. 

 What they do show is, that under the given circumstances, some 

 animals improve, others do not, but the capacity of those that 

 fail remains unknown. Even those that succeed do not divulge 

 all. Strictly speaking, their capacity is shown to be not less than 

 the records indicate, but actually it may be considerably more. 



The animals that improve emphasize a practical question of 

 some importance. There are plainly two ways of solving the tank 

 problem; by increasing speed, and by decreasing the length of 

 the pathway. Cases in which these two go hand in hand, or in 

 which constancy of speed is offset by an abbreviation of the path- 

 way, offer no difficulty; but what shall we say when increased 

 complexity of the pathway is compensated for by heightened 

 speed? If we limit ourselves entirely to the objective time meas- 

 urements, such an individual may seem to improve or to hold its 

 own; if, on the other hand, we study the pathway alone, the ani- 

 mal is clearly loosing in fitness. The sixth trial in series A is a 

 concrete illustration. How shall such an individual be rated? 



