ATTENTION. 



443 



It is for this reason that men have no eyes but for those 

 aspects of things which thej have already been taught to 

 discern. Any one of us can notice a phenomenon after it 

 has once been pointed out, which not one in ten thousand 

 couki ever have discovered for himself. Even in poetry 

 and the arts, some one has to come and tell us what aspects 

 we may single out, and what effects we may admire, before 

 our aesthetic nature can '■ dilate ' to its full extent and never 

 'with the wrong emotion.' In kindergarten instruction one 

 of the exercises is to make the children see how many 

 features they can point out in such an object as a flower or 



not satisfied with the explanation, fatigue of the sense-organ, which he 

 gives. "In quietly lying and contemplating a wall-paper pattern, some- 

 times it is the ground, sometimes the design, which is clearer and conse- 

 quently comes nearer. . . . Arabesques of mouochromic many-convoluted 

 lines now strike us as composed of one, now of another conuected linear 

 system, and all without any intention on our part. [This is beautifully 

 seen in Moorish patterns ; but a simple diagram like Fig. 39 also shows it 

 well. We see it sometimes as two 

 large triangles superposed, some- 

 times as a hexagon with angles 

 spanning its sides, sometimes as six 

 small triangles stuck together at 

 their corners.] . . . Often it hap- 

 pens in revery that when we stare 

 at a picture, suddenly some one of 

 its features will be lit up with es- 

 pecial clearness, although neither 

 its optical character nor its mean- 

 ing discloses any motive for such 

 an arousal of the attention. . . . 

 To one in process of becoming 

 drowsy the surroundings alter- 

 nately fade into darkness and 

 abruptly brighten up The talk of 

 the bystanders seems now to come 

 from indefinite distances ; but at the next moment it startles us by 

 its threatening loudness at our ver}' ear," etc. These variations, wliich 

 everyone will have noticed, are, it seems to me, easily explicable by the 

 very unstable equilibrium of our ideational centres, of which constant 

 change is the law. We conceke one set of lines as object, the other as 

 background, and forthwith the first set becomes the set we see. There 

 need be no logical motive for the conceptual change, the irradiations of 

 brain-tracts by each other, according to accidents of nutrition, ' like sparKs 

 in burnt-up paper,' suffice. The changes during drowsiness are still more 

 obviously due to this cause. 



Fig. 39. 



