lyS THE SOCIAL LIFE OF ANIMALS 



food and its own feeding mechanism is set off as a 

 result of this visual experience, even though its own 

 hunger might not have been sufficient to stimulate 

 feeding behavior. It is difficult to say to what ex- 

 tent such behavior is an expression of competition 

 as contrasted with unconscious co-operation. The 

 two types of motivation overlap here and elsewhere. 



The evidence which we have been considering 

 furthers our understanding of the fundamental na- 

 ture of group activities among many animals, some 

 of which are not usually regarded as being truly so- 

 cial. The whole emphasis of this chapter has been 

 laid upon facilitation as the result of greater num- 

 bers being present. This kind of social facilitation 

 has been described for such diverse processes as breed- 

 ing behavior, eating, working and learning. 



Added numbers do not always facilitate these ac- 

 tivities, as was shown by the analyses of the effect 

 of numbers upon the rate of learning. With some 

 animals, for example men and goldfish, under cer- 

 tain situations, learning is more rapid with several 

 present; but with others, such as parrakeets and mud- 

 minnows, under the conditions tested, increased num- 

 bers lead to a lower rate of learning. It seems that 

 no all-inclusive positive statement can as yet be made 

 in this field. One can, however, make the affirmation 

 that in the general realm here considered the pres- 



