The Human Mind; A Text-Book of Psychology Volume 1

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1892 edition. Excerpt: ...of the 'visual angle' subtended by this. As objects recede their retinal pictures decrease in area, whereas when they approach they increase. Whenever the object is a familiar one, a tree, a house, or a sheep, these variations of apparent magnitude are auxiliary signs of the distance of the object. Thus in looking across a Swiss valley we judge of the distance of the opposite mountain-side by the apparent magnitude of the chalets, the goats, and so on. Painters when they want to emphasise distance make use of this circumstance by introducing in the background a familiar form. The development of the perception of distance in the infant has been observed in close connexion with that of direction. We see the child at first unable to adjust the movements of its eyes to objects at different distances, and for a still longer time unable to co-ordinate its arm-movements with its visual 1 On the discriminative aspect of these muscular sensations see above, p. 128; cf. Wundt, Physiol. Psychology, H. p. 118. impressions. Children appear to attain to the distinction between what they can reach with their hand and what they cannot only after some months have passed. In the case of one otherwise intelligent child it was not perfect till about the end of the sixth month. And it was observed that another child tried to reach the lamp of a railway compartment when over a year old. As all observers of children know, it is some years before they become ready in distinguishing and recognising the signs of more remote distance.1 § 19. Perception of Real Magnitude. The real magnitude of an object is directly known by means of active touch, armmovement accompanied by contact, or, if the object is a large one, as a wall, by the aid of locomotion as well....