PERCEPTION. 139 



are at present known concerning the time-relations observ- 

 able in Perception, because with reference to the theory of 

 the rise of consciousness, and also of the physiological side 

 of mental evolution in general, these facts are of the highest 

 importance. They prove by actual measurement that the 

 simplest psychical actions are slow as compared with reflex 

 actions, that they can be rendered more rapid by practice, , 

 but that they can never be brought to be so rapid as reflex 

 actions. We have a further exemplification of the effects of 

 practice in thus quickening the act of perception in the 

 higher stages of the process. For universally the effect of 

 previous acts of perception is that of placing the mind in 

 readiness, as it were, for performing acts of the same kind. 

 The mental attitude as regards these particular acts of per- 

 ception is then the attitude of what Lewes appropriately 

 called pre-perception.* When the pre-perceptive stage is 

 well established, the memory, or the memory and inference 

 as the case may be, arise in or together with the act of per- 

 ception, so forming an integral part of the act. It is owing 

 to the want of special experiences that young children are so 

 slow in forming perceptions of more than the lowest degree of 

 complexity ; as Mr. Spencer observes, they take a long time 

 to " integrate " a strange face or other unfamiliar object ; and 

 this, otherwise stated, means that their mental attitude of 

 pre-perception has not yet been fully attained for such and 

 such classes of objects ; the processes of memory, classifica- 

 tion, and inference do not occur immediately in the act of 

 perception, and therefore the full mental interpretation of the 

 object perceived is only arrived at by degrees. Similarly, in 

 adult life the powers of perception may be trained to a mar- 

 vellous extent in special lines by practice, as we have already 

 seen in the example of Houdin's son, and as we may also see 

 in the fact that an " artist sees details where to other eyes 

 there is a vague or confused mass." The influence of per- 

 sistent attention is the most important of all influences in 

 developing the rapidity and accuracy of the perceptive 

 powers in which their highest excellence consists. 



We have now to consider the important question whether jj 



* Problems of Life and Mind, 3rd ser., p. 107. See also Dr. J. Hugh- 

 lings Jackson in Brain, Nos. Ill and IV ; and Mr. Sully, in Illusions, pp. 

 27-30. 



