INSTINCTS AND HABITS IN CHICKS 47 



to. The shock was not severe enough to cause the chick to 

 jump from the wires or chirp on receiving it. It was found 

 that a shock from a current value of about 1.69 amperes with 

 the secondary coil set at 5.5 according to the scale on the indue- 

 to rium, proved most generally satisfactory. Here again there 

 were individual differences in sensitiveness among the chicks, 

 but in the main the above shock brought results without being 

 injurious, and had no more effect on the chicks than to start 

 them from their position, occasionally causing one to lift a 

 foot from the wires. The floor of the entrance box was kept 

 wet so that the feet of the chicks would be in a condition to 

 receive the shock with regularity. 



At first a chick usually ran right over the wires and on to 

 the front netting, from which there was a full view of the other 

 chicks in the cage. With the chick in this position on the 

 " wrong " side, it was found best to wait until it happened 

 upon the right road out by its own random activity. Some 

 times the wait on the first training trial was ten minutes, but 

 such a delay was exceptional. The young chicks, as a rule, were 

 active and soon acquired the habit of withdrawing from the 

 " wrong " side promptly. The draft on the experimenter's 

 time after the training was well under way, averaged about 

 1.5 minutes per reaction, including everything. No trouble was 

 experienced with hesitancy on the part of the chicks to return 

 over the electric wires. Of course they were never shocked 

 on the return passage. » 



In a series of trials the positive card was shifted right and 

 left in this order: r, 1, r, 1, r, r, 1, 1, r, 1. Thus each card in each 

 series was displayed the same number of times on the right- 

 and left-hand sides. When the chick had made a series of error- 

 less reactions with the above changes of cards, it was tested 

 for another perfect series with a different order and an equal 

 number of rights and lefts. If no errors were made this time, a 

 third series with still a different sequence of changes was given, 

 when, if the chick reacted without error, the process of habit- 

 formation was pronounced completed. 



In none of the work with this apparatus was it necessary 

 to starve the chick or even to keep it excessively hungry. It 

 is my opinion that hunger did not play a more important part 

 than the reaction to confinement and solitude. True, it is easy 



