36 FREDERICK S. BREED 



influence accelerates improvement in the accuracy of the re- 

 action studied. 



The curve for no. 8i clearly suggests retardation of develop- 

 ment — a very interesting fact, if due to the isolation. At first 

 this animal seemed quite indifferent to food. Besides, its toes 

 were bent under in such a way that it looked crippled. In a 

 few days, however, neither of these failings was observable. 

 They may indicate that the chick was slow in the process of 

 imfoldment in more respects than in pecking. It would hardly 

 be fair, for example, to attribute the slow expansion of the 

 toes to the isolation. No. 8i turned out to be a fine animal. 

 The rapidity with which the components of reaction 4 became 

 integrated, once the process set in, is instructive. The maxi- 

 mum of accuracy attained, as well as the high average main- 

 tained, mark the nicety of adjustment in no. 8i's pecking 

 mechanism. 



If chicks that are isolated peck with a normal degree of accu- 

 racy within the natural time limit, and chicks stimulated by 

 the presence of others much more efficient than themselves fail 

 to show a supernormal rate of improvement, one has good 

 grounds for believing that the social influence, whatever else its 

 effect, does not appreciably modify the natural course of develop- 

 ment of the pecking concatenation. 



In fig. 7 are presented the curves of development of the peck- 

 ing reaction, based on the averages obtained from the records 

 of the twenty-one chicks in Groups C, E, and F during their 

 first twenty-four days. The data for these curves are given in 

 table 7. Curves I, II, and III, standing for reaction i, 2, 

 and 3, respectively, represent, as explained before, the distribu- 

 tion of errors. Curve IV represents reaction 4. The sum of 

 the heights of the error curves above the base line on any given 

 day will equal the distance of Curve IV below its limit for the 

 same day. 



"In nearly all cases, as one might expect," says Morgan,' 

 " the simple process of striking is more accurate than the more 

 complicated process of striking and seizing; and this, again, 

 than the yet more elaborate process of striking, seizing, and 

 swallowing." From the data in table 7 it is an easy matter 

 not only to substantiate this assertion, but to show the quanti- 



' Morgan, C. L.: Habit and instinct. London and New York, 1896, p. 37. 



