BIOPSYCHOLOGICAL ^ 605 



pared, for instance, with a young ant ! It is true that almost from 

 the first they can peck with precision at flies moving on the wall 

 of the hen-run; that they can jump neatly from an eminence eight 

 times their own height ; that they can scratch their head with their 

 toes; and that they have a few other instinctive accomplishments. 

 But the remarkable fact is the small ness of their repertory. Chicks 

 hatched out in an incubator paid no attention at all when their 

 unseen and previously unheard mother clucked outside the door. 

 They are not instinctively aware that the presence of a cat spells 

 danger. Even when thirsty they do not instinctively recognise 

 water, though they may be standing in a saucerful. They will stuff 

 their crop once or twice with worms of red worsted — a very unprofit- 

 able meal. 



Yet how quickly they learn to recognise four or more sounds 

 which have "meaning" for them, to discriminate between profitable 

 and unprofitable food-materials, to reject positively dangerous 

 food, such as bees, and so on! There are few animals so educable 

 as chicks — up to their limits. It is impossible to believe that there 

 has been any racial degeneration of the brain in creatures so quick 

 to learn; and it is very difficult to believe that educability disap- 

 pears in the adult hen. More probably it simply falls into desuetude, 

 because it is so rarely stimulated in a sufficiently interesting way. 



This view is supported by some careful experiments made by Katz 

 and Revesz. When they scattered mixed rice and wheat before their 

 hens, they noticed that the grains of rice were always picked up 

 first. So they tried a hungry hen with twenty rice grains which were 

 glued irregularly to a slab of wood about five inches square; and 

 between these they placed ten loose grains of wheat. At first the 

 hen tried the rice grains, glued down quite imperceptibly, but could 

 not detach them. It then picked up the grains of wheat. When all 

 the ten were picked up, there was a rest for fifteen seconds, and then 

 the hen got another similar lesson, and so on until it had seven. 

 On each occasion the observers counted the number of pecks that 

 the hen made before all the ten grains of wheat were swallowed. 

 The figures are very interesting: 35, 19, 19, 16, 12, 10, 10. In other 

 words, the hen had learned by the sixth lesson not to waste time 

 over the rice grains. It inhibited and eliminated useless movements; 

 and we have cited this case, which does not stand alone, not to show 

 that hens are not so stupid as they look, but because it illustrates 

 the value of educational methods that evoke interest. 



{lla) HABITUATION OF INTELLIGENT ACTIONS.— An in- 

 telligent sequence of actions, requiring, to begin with, perceptual 

 behaviour at many a turn may be repeated so often that it passes 

 into habituation or enregistration. Practice makes perfect; and an 

 intricate concatenation, as in the musician's triumphant skill, may 



