328 NATURAL SCIENCE. May, 



Acquired automatism : the individually modified physiological 

 basis of the performance of acquired movements or activities which 

 have been stereotyped by repetition. 



There is certainly some overlap in the definitions, and it is 

 difficult to see how such overlap is to be avoided. The physiological 

 rhythms — such as the heart-beat, respiratory movements, and peri- 

 staltic action — are in part automatic, in the physiological sense of 

 originating within the organ which manifests the rhythm ; but they 

 are also in part reflex. The line between reflex movements and 

 instinctive activities cannot be a very rigid one ; instinctive activities 

 are indeed in large degree organised trains or sequences of 

 coordinated reflex movements. 



Although the psychological aspect of instinctive activities falls 

 under the general head of impulse, yet impulse is broader than 

 instinct — that is, if we adopt the definitions above suggested. On the 

 one hand, some reflex movements are probably accompanied by 

 impulse. On the other hand, when intelligent activities pass into 

 habits through repetition, the performance of these habits is prompted 

 by impulse. Impulse may, in fact, be either connate or acquired, and 

 may be associated both with automatism and with control. Instinct 

 is a form of connate impulse. As such it may be counteracted or 

 modified by an acquired impulse due to pleasurable or painful experi- 

 ence. A chick, for example, which has run after and seized a 

 cinnabar caterpillar, acquires through experience a counteracting 

 impulse due to the disagreeable effect. The connate impulses, termed 

 instincts, may thus be modified by acquired impulses which result 

 from experience ; but there is seldom or never a conflict of instincts, 

 as these are above defined. 



Whether the objective activities termed instinctive are always 

 accompanied by the subjective connate impulse termed instinct is a 

 question which is open to discussion. 



A wider definition of instinct by which it would be synonymous 

 with connate impulse may be suggested as an alternative to that 

 above given. This would, perhaps, be more in accord with the 

 popular use of the word " instinctive," but it appears to be less 

 satisfactory as a definition of the technical term. 



It is well to distinguish motives, as the determinants of deliberate 

 acts, from the acquired impulses which are the determinants of intelli- 

 gent activities as above defined. As the intelligent activity is often 

 the outcome of a conflict of impulses, so is the deliberate act the out- 

 come of a conflict of motives. 



Mimetic activities are due to a mimetic impulse. Some of them 

 are probably involuntary and due to connate impulse ; but others are 

 cercainly due to intelligent imitation. They form a group sufficiently 

 well-defined to warrant the distinct place assigned to them in the 

 suggested scheme. 



