IS 

 successive days* Thus for rats given one trial a day the 



average would be taken of three trials, others given three 



trials of nine trials and still others given five trials 



of fifteen trials. It was scarcely, if ever, a difficult 



norm to reach for many of the more active rats entered the 



box in one quarter to one half of a second and the less 



active ones close on to one second, or finally in one second. 



This norm cannot he considered low, hut on the contrary a 



moderately high one, as the slowest rats found it rather 



difficult to reach. Rats would reach this norm in one 



second or less when they went directly to the door and 



lifted the latch with their snouts. Any unusual way of 



opening the door or habitually going around the box would 



increase the time considerably. For these cases the time 



varied from one second and a half to two seconds. The norm 



was then taken at two seconds. '.Vhen either norm was 



reached learning was assumed to be complete. The rats 



were then held for retention. which test was taken after 



