DELAYED REACTION 27 



left the release box. At first this curtain was also continued 

 between R and T. Subsequently, this was found to be both 

 inconvenient and unnecessary and its use was discontinued. 

 The apparatus was wired so that any light could be turned on 

 at will and so that any push button could be connected with 

 the buzzer. Moving the switches was done without the sub- 

 ject's knowledge. The light was always turned on over the 

 button that rang the buzzer. The child's problem was to find 

 this button at the first trial when the light was on (in the 

 learning series) and then (in the delayed reactions) after the 

 light had been turned oft' for a certain interval of time. 



The general method of experimentation was as follows: The 

 animal to be tested was put in the release box, R, of problem 

 Box C, for example. If, now, the lighted box is the one on the 

 left, the exit doors of the others are closed and the switches at 

 S are so set that if the experimenter close the switch at S", the 

 animal will receive a shock if it steps on either the strips leading 

 to the box on the right or on those leading to the one in front. 

 The light is then turned on in the left box. The animal is re- 

 leased after five seconds, the time being taken with a metro- 

 nome. A careful, detailed record is kept of the direction in 

 which the animal is oriented'" when released and of just where 

 it goes after being released. In the case of the animals used in 

 Boxes A, B and C, they should go straight to the lighted box, 

 out through the exit doors and back to the entrance of the 

 release box w^here they are fed. The rats used in Box D were 

 fed a small morsel of bread and milk at the exit doors of the 

 lighted boxes. Theoretically the olfactory control was not so 

 good here as where no food at all was given in the light boxes. 

 Practically, there was no difterence. The rat was given only 

 a bite, so almost no food fell on the floor; all the boxes were 

 used an equal number of times ; and all were frequently washed 

 out. Whatever odor was present was so distributed as to afford 

 no appreciable basis for discrimination. The results obtained 

 with these rats, when compared with those where the olfactory 

 control was better, support this statement. In any event, 



■*" Orientations are spoken of as right and wrong, irrespective of whether an 

 animal may be said to depend on them as cues or not. When the orientation is 

 "right," the animal is headed toward the proper box. Any other orientation is 

 "wrong." 



