DEFINITION OF INSTINCTIVE BEHAVIOUR 6s 
careful and patient investigation. ‘“ Under the term Instinct,” 
they say, “we place all complex acts which are performed 
previous to experience, and in a similar manner by all members 
of the same sex and race, leaving out as non-essential, at this 
time, the question of whether they are or are not accompanied 
by consciousness.” * 
It may be said, however, that some reference to the conscious 
aspect of instinctive behaviour is implied by saying that the 
acts are performed without instruction or experience. But the 
reference at present is wholly negative. We may say, as 
the result of observation, that instinctive acts are performed 
under such circumstances as exclude the possibility of guidance 
in the light of individual experience, and render it in the 
highest degree improbable that there exists any idea of the end 
to be attained. But this is a very different position from that 
of asserting the presence of a positive faculty or propensity 
which impels an animal to the performance of certain actions. 
This it is which, from the observational point of view, is 
unnecessary. For the reference of a given type of observed 
behaviour to a “propensity” so to behave or to a “ faculty ” 
of thus behaving, is no more helpful than the reference of the 
development of any given type of structure toa ‘‘ potentiality ” 
so to develop. We may, therefore, without loss of precision, 
simplify Spence’s definition by stating that instinctive behaviour 
is independent of instruction and experience, and tends to the 
well-being of the individual and the preservation of the species. 
Let us next consider the clause which affirms that instinctive 
behaviour is prior to experience. This is well in line with the 
distinction now drawn by biologists between congenital and 
acquired characters. It refers them to the former category, and 
implies that the organic mechanism by which they are rendered 
possible is of germinal origin. This is not, however, universally 
admitted. Professor Wundt, for example, approaching the 
subject from the point of view afforded by the study of man 
and the higher animals, gives to the term a wider meaning, 
* George W. and Elizabeth G. Peckham, “On the Instincts and 
Habits of the Solitary Wasps,” p. 231. 
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