44 G. V. HAMILTON 



traced the way back without error, although he had been over 

 the various roads involved less frequently than had his master. 



III. TABULATION AND PRELIMINARY ANALYSIS OF RESULTS 



It will be remembered that each of the subjects was given 

 loo trials, and that during each of these trials one, but only 

 one, of the four exit doors was capable of being opened. It 

 will be further remembered that this " unlocked " door varied 

 from trial to trial. Thus, if Door 3 were unlocked for any present 

 trial it would surely be locked for the next trial. It is apparent, 

 therefore, that any subject who avoided, during each present 

 trial, the unlocked door of the immediately preceding trial, 

 was apt to effect his escape during his 100 trials by trying the 

 various exit doors 200 or 201 times: 200 times if he did not 

 try all four doors during his first trial, otherwise, 201 times. 



Again, any subject who tried the various doors without refer- 

 ence to the ever yarying one impossible door as such, or as a 

 preferable door to try on account of its having just afforded 

 the escape, would be apt to effect his escape from the apparatus 

 necessary 100 times by trying the various exit doors 250 times. 



The " average " number of efforts to open exit doors would 

 be affected by any of the following factors: 



(i) This number would be decreased by a tendency to try 

 first, on entering the apparatus for a trial, the exit door that 

 had been most remotely (in time, with reference to the present 

 trial) an unlocked door. This, in spite of the fact that the ex- 

 perimenter followed an irregular order in selecting exit doors 

 for unlocking. 



(2) It would be increased by a tendency to prefer, as first 

 choice of door to be tried during a given trial, the unlocked 

 door of the immediately preceding trial. 



(3) It would be increased by a tendency to make more than 

 one separate effort to open the same exit door during a given trial. 



In table i, I have tabulated the total number of separate 

 efforts to open exit doors manifested by each of the various 

 subjects during his 100 trials. In making current observations 

 of my subjects' behavior I recorded as a separate effort to open 

 an exit door the total activity of a subject from the time he 

 attacked an exit door until he left its immediate vicinity. For 

 example, during his second trial Dog 18F1 went to Door 4 and 



