84 The Recapitulation Theory and Human Infancy 



in simpler fashion. As to the excitants of attention, curiosity, 

 and their derivative "interests," it is probable that the more 

 conspicuous of these (such as sensory intensity, massiveness, 

 visible motion), are common to children and adults. The 

 strange-in-the-familiar as an incitement to attention and thought 

 apparently affects both alike. Much of the " peculiarity " 

 assigned to children's interest in natural phenomena and in 

 the images of their minds can with practical certainty be assigned 

 to the unlikeness in apperceiving content due to intellectual 

 immaturity. The incitements to activity seem very closely 

 related to children's capacities; when they find they are able to 

 grasp they are interested in grasping, when they discover they 

 can walk or climb, they take to these things with avidity, and so 

 on through the succession of childish, youthful, and adolescent 

 "activities." In these things childhood and youth are very 

 obviously preparatory. Excitants are here nicely adjusted to 

 disposing the young animal to undertake his own education the 

 moment the underlying structures are ready. 



It is generally assumed that instinct represents the ancient 

 basic structure upon which plasticity has supervened. A natural 

 inference would identify the native excitant as the original cue 

 to the unmodifiable action which preceded the plastic or habit- 

 induced action in the phylogeny. This is of course not necessari- 

 ly the case, for the original cue may have altered in descent along 

 with the supervening plasticity, in accordance with the theory of 

 organic selection. However, it is at least likely that the native 

 excitant is a conservative and comparatively ancient feature 

 of psycho-physical organization, even if it has not remained 

 wholly unchanged. If this is so, the progression in the infant 

 from the native excitant to the "meaning" which absorbs it, is 

 homologous with the original phyletic progression from the 

 ancient sensori-motor to the percept-motor action system, and 

 we are apparently confronted with a genuine case of ontogenetic 

 rehearsal or "recapitulation." 



If now we turn to the motor aspect of the presumably ancient 

 instinctive structure we find the distinction, commonly assumed, 

 between its inherited and involuntary expressions and the ac- 

 quired habits which grow up with use and exercise. But the case 

 here is not the same as with excitants and meanings. Plasticity 

 presumably has not been merely added to instinctive muscular 



