80 HAROLD C. BINGHAM 



chick's weight released the trip. The chicks readily learned 

 to approach close to the door of the exit which brought them 

 upon the tripping device. As the weight of the growing chicks 

 increased the exit automatically opened when they stepped 

 on the tripping device. The electric shock was not intro- 

 duced until the fourth training series. 



In the first two series of training, the visual stimuli differed 

 with respect only to flicker. This was a period of training 

 during which the chick's task was chiefly to learn the primary 

 problem. Visual discrimination was encouraged at the begin- 

 ning of the third series by presenting stimuli differing with 

 respect to several factors. This third series may be regarded 

 as transitional between the primary and secondary tasks. It is 

 the last series during which the time record was made from 

 start to exit. In subsequent series the time record represents 

 the number of seconds elapsing between entrance to the discrim- 

 ination chamber and choice of a compartment. If the choice 

 happened to be wrong (— ), therefore, considerable time 

 might subsequently elapse beteeen the choice and the escape, 

 whereas the time elapsing between choice of the + compart- 

 ment and escape was regularly measurable only in fractions of 

 a second. The maze problem, it was assumed, was sufficiently 

 learned at the end of the third series to permit introduction of 

 the secondary task of discrimination and correct choosing. 



For further comparison of the characteristic? of the chicks 

 during the preliminary series, table 14 is presented. This 

 table indicates the number of times right or left sides and + 

 or — stimuli were successively chosen throughout the first two 

 preference (preliminary) series. Frequency of change is greater 

 as the number of successive choices of the same side or the 

 same stimulus is smaller. The total number of changes is 

 indicated by the number in the first column which stands on 

 the same line with the last record in any other column. For 

 convenience the total number of changes in choice of sides or 

 stimuli is indicated at the bottom of each column. Persistence 

 in choosing is assumed to be greater as the number of recorded 

 changes is smaller. In other words, the fewer the changes 

 recorded for any individual, the greater is the indication of its 

 persistence in following up a particular fine of response. 



