92 WALLACE CRAIG. 



phasic contractions of many skeletal and dermal muscles, giving 

 rise to bodily attitudes and gestures which are easily recognized 

 signs or "expressions" of appetite or of aversion; by restlessness; 

 by activity, in extreme cases violent activity; and by "varied 

 effort" (Lloyd Morgan, '96, 7, 122, 154; Stout, '07, 261, 267). 



In the theoretically simplest case, which I think we may ob- 

 serve in doves to some extent, these states bring about the 

 appeted situation in a simple mechanical manner. The or- 

 ganism is disturbed, actively moving, in one situation, but quiet 

 and inactive in another; hence it tends to move out of the first 

 situation and to remain in the second, obeying essentially the 

 same law as is seen in the physical laboratory when sand or lyco- 

 podium powder on a sounding body leaves the antinodes and 

 comes to rest in the nodes. 



But pigeons seldom are guided in so simple a manner. Their 

 behavior involves other factors which must be described in con- 

 nection with appetite and aversion. 



An appetite is accompanied by a certain readiness to act. 

 When most fully predetermined, this has the form of a chain 

 reflex. But in the case of most supposedly innate chain reflexes, 

 the reactions of the beginning or middle part of the series are not 

 innate, or not completely innate, but must be learned by trial. 

 The end action of the series, the consummatory action, is always 

 innate. One evidence of this is the fact that in the first 1 manifes- 



1 To see the appetitive nature of an instinct, it is necessary in some cases to 

 observe an individual animal carefully during its first performance of the act in 

 question. But the performance may be so quick that the observer is quite unable 

 to analyze it. Analysis may be aided by preventing the animal from attaining 

 the consummatory situation for a time, so that the appetitive phase is prolonged, 

 as it were magnified. My cripple dove (example 5, p. 99) afforded just this aid 

 to analysis. The literature is full of reports of instinctive behavior which might 

 well be further analyzed. Consider for example the case of the young moorhen 

 cited by Lloyd Morgan ('96, 63) which had never previously dived, but on being 

 suddenly frightened by a puppy, dived like a flash. That act was too quick for 

 us to analyze it. But if we could successfully impede the diving of a young moorhen 

 so as to prolong the phases of the act, I think it probable that we should find an 

 appetite for the consummatory situation (that of being under water) and a restless 

 striving until it is attained; and that some details in the series of actions, details 

 which in a normal dive are very sure to be hit upon by accident, are not innately 

 predetermined. When one sees the first performance of an instinctive act take 

 place very quickly and with apparent perfection, this does not prove that there 

 is an innate chain reflex determining every detail of the act. 



