278 



J. F. SHEPARD AND F. S. BREED 



ss 



they soon lapsed into inactivity aga'n. A turning point in 

 their behavior came when they succeeded in swallowing a grain 

 after one of their more or less indifferent pecks. Energetic 

 pecking thereupon ensued. The contrast between an animal's 

 attitudes before and after swallowing a grain of its own peck- 

 ing was very marked. Anthropomorphically speaking, one 

 might well say the trouble with the animal was that it did not 

 know what the food particles were or were for. 



DAY5 



Figure 1. — Curves showing the course of development of the pecking instinct 

 after artificial delay. S, standard curve, representing rate of improvement 

 in accuracy under natural conditions. I, III, IV, and V, curves for corres- 

 ponding groups of chicks in which the action of the instinct has been artifi- 

 cially prevented for three, three, four, and five days respectively, previous to 

 the first tests. Data in table 1. 



RESULTS OF PECKING TESTS 



Two lots cf chicks, divided into five groups, in all twenty- 

 three in number, were tested. These groups were designated 

 by the Roman numerals I, II, III, IV, and V. In figure i the 

 corresponding curves for the several groups are designated by 

 these same numerals. Each curve represents the course of 

 development of the complete feeding coordination, that is, of 

 reaction 4, fqr a given group. The number of perfect reactions 

 in a series of fifty pecking reactions, the first fifty, on any given 

 day, is assumed to be an index of the accuracy of the pecking 



