DEVELOPMENT OF COLOUR VLSION IN THE CHILD 155 



and that novelty may play an important part in determining the infant's 

 choice of colour. He is strongly of opinion that such experiments do 

 not afford evidence of the course of the development of colour sense. 

 He says, "It is true that the positive results of such experiments may 

 be significant. When, for example, a child shows a distinct preference 

 for yellow, presented with white, that is a clear indication that yellow 

 has a different effect on him from white. And we are doubtless justified 

 in assuming that this difference is not merely an affective and physio- 

 logical one, producing greater pleasurable excitement in the infant and 

 determining the choice of the brick which is grasped, but that it is 

 also of sensational significance, that is to say, the visual sensation 

 excited by yellow is different in the infant from that excited by white. 



" I think it highly probable that the primary physiological basis of 

 colour vision is completely installed before the infant has reached the 

 stage when he can successfullv dift'erentiate from one another all the 

 various colour sensations which such an apparatus permits him to receive ; 

 just as, in foetal life, he is provided with lungs before he can make use 

 of them. If this be true, then it follows that the gradual differentiation 

 of the colour sensations from one another is a process distinct from the 

 developing constituents of the peripheral cerebro-retinal apparatus." 



Valentine commenced his experiments on a child at the age of three 

 months, before grasping was sufficiently developed to be of use. The 

 method he adopted was to measure the time the child looked at either 

 of two coloured wools held before him for two minutes at a time. The 

 colours used were black, white, red, yellow, green, blue, violet, pink and 

 brown. The following table gives all the scores (in seconds) of each 

 colour, together with the scores against them. 



