42 Animal Intelligence 
our purpose all these matters count little, and we may take 
the general slope of the curve as represeniing very fairly 
the progress of the association. The sloperf any particular 
part of it may be due to accident. Thus, very often the 
second experience may have a higher time-point than the 
first, because the first few successes may all be entirely 
due to accidentally hitting the loop, or whatever it is, and 
whether the accident will happen sooner in one trial than 
another is then a matter of chance. Considering the general 
-slope, it is, of course, apparent that a-_gradual descent — say, 
from initial times of 300 sec. to a constant time of 6 or 8 sec. 
in the course of 20 to 30 trials —represents a difficult 
association; while an abrupt descent, say in 5 trials, froma 
similar initial height, represents a very easy association. © 
Thus, 2 in Z, on page 57, is a hard, and 1 in I, on page 49, 
an easy association. 
In boxes A, C, D, E, I, 100 per cent of the cats given a 
chance to do so, hit upon the movement and formed the 
association. The following table shows the results where 
some cats failed: — 
TaBLe I 
No. Cats TriED No. Cats FamepD 
Awtarn 
ano on 
HHNHwN PS 
The time-curves follow. By referring to the description — 
of apparatus they will be easily understood. Each mm. 
along the abscissa represents one trial. Each mm. above 
it represents 10 seconds. 
These time-curves show, in the first place, what associa- 
