MENTAL IMAGERY. 



75 



I could mention instances within my own experience in which the 

 visualizing faculty has become strengthened by practice ; notably one 

 of an eminent engineer, who had the power of recalling form with un- 

 usual precision, but not color. A few weeks after he had replied to 

 my questions, he told me that my inquiries had induced him to practice 

 his color memory, and that he had done so with such success that he 

 had become quite an adept at it, and that the newly acquired power 

 was a source of much pleasure to him. 



The memories we should aim at acquiring are chiefly such as are 

 based on a thorough understanding of the objects observed. In no 

 case is this more surely effected than in the processes of mechanical 

 drawing, where the intended structure has to be portrayed so exactly 

 in plan, elevation, side view, and sections, that the workman has simjjly 

 to copy the drawing in metal, wood, or stone, as the case may be. It 

 is undoubtedly the fact that mechanicians, engineers, and architects 

 possess the faculty of seeing mental images with remarkable clearness 

 and precision. 



A few dots like those of the Bushmen give great assistance in cre- 

 ating an imaginary picture, as proved by our general habit of working 

 out new ideas by the help of marks and rude lines. The use of dolls 

 by children also testifies to the value of an objective support in the 

 construction of mental images. The doll serves as a kind of skeleton 

 for the child to clothe with fantastic attributes, and the less individu- 

 ality the doll has, the more it is appreciated by the child, who can the 

 better utilize it as a lay figure in many different characters. The art of 

 strengthening visual as well as every other form of memory lies in 

 multiplying associations ; the healthiest memory being that in which 

 all the associations are logical, and toward which all the senses concur 

 in their due proportions. It is wonderful how much the vividness of 

 a recollection is increased when two or more lines of association are 

 simultaneously excited. 



It is a mistake to suppose that a powerful exercise of the will can 

 vivify a faint image. The action of the will is negative, being limited 

 to the suppression of what is not wanted and would be in the way. 

 It can not create thought, but it can prevent thoughts from establish- 

 ing themselves which lead in a false direction ; so it keeps the course 

 clear for a logical sequence of them. But, if appropriate ideas do not 

 come of their own accord, the will is powerless to evoke them. Thus, 

 when we forget a familiar name, it is impossible to recall it by force of 

 will. The only plan in such cases is to think of other things, till some 

 chance association suggests the name. The mind may be seriously 

 dulled by over-concentration, and will only recover its freshness by 

 such change of scene and occupation as will encourage freedom and 

 discursiveness in the flow of the ideas. 



All that remains to be said refers to the utility of the visualizing 

 faculty, and may be compressed into a few words. A visual image is 



