You will hear it stated, by some, that there are just two instincts, and that all instinctive behavior belongs under the head of one or the other of these two. The one is the instinct to preserve one's individual life, and the other is the instinct to propagate the species. Mating, nesting and care of the young come under the reproductive instinct, while feeding, flight from danger, and shunning extreme heat or cold are modes of self-preservation. This seems logical enough, but it is very bad psychology. It amounts to a classification of native reactions from an external point of view, without any consideration of the way the individual is organized.
Perhaps the most obvious objection to these two supposedly all-inclusive instincts is found in what has just been said, to the effect that some instinctive behavior has no known survival value. This amounts to saying that some instincts do not serve either the preservation of the individual or the propagation of the species; and such a statement is probably true, especially of human instincts.
But even if this objection should not hold, there is another, more radical one. Neither of these two big "instincts" is a behavior unit in any sense. Take the "instinct of self-preservation", for example. It would certainly have to include both feeding and escape from danger. But feeding and flight from danger do not belong in a single series [{116}] of acts; they are two distinct series, and represent two distinct tendencies. So distinct are they that, as we shall see in the next chapter, they are antagonistic. If the danger-avoiding tendency is aroused, the whole feeding and digestive activity is checked for the time being. The two instincts are antagonistic, in their actual operation; throw one into action, and you throw the other out. It is only from an external point of view that the two can be classed together; in the organization of the individual they are entirely separate.
Not much different is the "instinct of reproduction". In birds, to be sure, there is a fairly continuous series of reactions, that begins with mating, continues with nesting, laying eggs and incubating them, and ends in the care of the young birds. But in mammals there is no such continuous series of reproductive acts, but mating comes to a close and an interval elapses in which there is no behavior going on that has anything to do with reproduction.
Before giving a detailed list of the various human instincts, we shall do well to consider emotion, which is closely bound up with instinct.
EXERCISES
1. Outline the chapter.
2. Explain the differences between these three;
Action governed by instinct.
Action governed by habit.
Action governed by deliberation.
3. What is the objection to each of the following expressions?