704 COMPARATIVE AND GENETIC PSYCHOLOGY 



of the field discloses the fact that when the conditions of life are 

 constant and uniform, the instinctive factor, subject to organic 

 selection, predominates, and complex groups and trains of reflexes 

 assume a stereotyped form. This is due to what we may term 

 a biological coalescence of unit-situations into a coordinated whole. 

 What we call the instinctive behavior of many of the insects, for 

 example, seems to be the inherited grouping in biological sequence 

 of inherited units of response. But in relation to more varied cir- 

 cumstances the intelligent factor predominates. The hereditary 

 unit-situations may not be fewer, may indeed be more numerous. 

 But the manner of their coalescence and coordination is rather 

 psychological than biological. The higher animals exhibit an intelli- 

 gent plasticity which enables them to meet the requirements of 

 the more complex surroundings into which their life has risen, and 

 which is reflected or symbolized by the psychological environment. 

 Here a stereotyped coordination of the hereditary units of behavior 

 would be rather a hindrance than an advantage. The winning animal 

 in life's struggle would be the one in which behavior was most 

 rapidly and most surely modified to meet particular needs the 

 one in which the teachings of experience were most promptly used 

 in effective action. The inevitable tendency of the evolution of intelli- 

 gence must be the disintegration of stereotyped modes of behavior 

 as biologically coordinated wholes and the dissolution of instinctive 

 complexes into relatively independent instinct-units which would be 

 thus free to coalesce into new groups under the guidance of experi- 

 ence. Thus it is that in the more highly developed animals and in 

 the human subject the instinctive units assume rather the form of 

 a number of congenital tendencies or propensities than of instinct- 

 ively coordinated wholes of behavior, the former being less stereo- 

 typed than the latter. And thus it is that in them there is a shorter 

 or longer period of inefficiency during which the inherited unit- 

 situations are coordinated psychologically in new groups under the 

 influence of individual experience as a shaping environment. 



Throughout the whole range of perceptual development under 

 these conditions there is progressive integration and differentia- 

 tion of the unit-situations, always on essentially practical lines, 

 always in closest touch with active behavior. Even perception 

 itself, as genetic psychology has helped us more fully to realize, 

 is dependent on acquired habits of action. Perceptual meaning 

 and value are ever dependent on some activity directed toward 

 that which is so perceived. All differentiations within the pre- 

 sented situations are due to the call for some directed behavior, are 

 due to the demand for some focusing of active manipulation. 

 Thus is the mouse differentiated for the practical interests of the 

 kitten. And all integration of diverse situations is due to their 



