The Nature of Intelligence
Chapter 2. The Classification of Behaviour
L.L. Thurstone
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I. Antecedents and consequences of action
2. Stages of the psychological act
(a) Energy-source
(b) Lowered threshold for stimuli
(c) Deliberate ideation
(d) The internal stimulus
(e) Imaginal hunt for external stimuli
(f) Overt hunt for external stimuli
(g) The external stimulus
(h) The consummatory overt act
(i) Overt consequences of the act
(k) Satisfaction to the actor and quiescence at the energy-source
I. ANTECEDENTS AND CONSEQUENCES OF ACTION
One of the basic problems in psychology is necessarily the classification of actions and their incomplete forms which constitute conscious life. There are different bases by which actions may be classified. The simplest of these is that of direct similarity of the overt acts themselves. To pick up a fork, and to pick up a fountain-pen, are two acts that are closely similar, and they may for certain narrow purposes be classified together. Psychologically two such actions
(25) are totally different in two respects. The mental antecedents of the two overt acts are totally different, and the consequences and immediate satisfactions are also different. If we compare the two psychological acts that are involved we find that they converge at one point only, namely at the point where the motives or purposes issue into overt expressions. Before and after this point the two acts and their consequences cannot be classified together. From the standpoint of the psychologist it is a negligible circumstance that the two psychological acts happen to terminate in the same muscle groups.
We may proceed in either direction, through the antecedents or through the consequences of the act, in order to discover other bases for classifying action. Let us go to the antecedents first. If two psychological acts are similar in the mental antecedents of the overt acts, the two resulting actions may for that reason be classified together. Suppose you discover that you should have given some information to another man. This is a mental state and it is therefore unfinished action. The resulting overt formulation of the psychological act may take various forms. You may reach for the telephone, or you may put on your hat and coat and walk out. These two seen forms of behaviour are, of course, different in appearance, but there was a point in the mental antecedents of two such possible actions at which they would be identical, namely that stage in the formulation of behaviour which is merely the realization that some information should be conveyed. Two widely different overt acts may, then, have converged, and they may have been identical, at some mental antecedent stage. We see that if
( 26) we define the psychological act as the whole course of events from a purpose or motive, through its imaginal form, through the overt expression, to the consequences and satisfactions to the actor, we have numerous points at which different psychological acts may be treated as identical even though they differ widely at other stages.
Two acts may be declared to be in the same category because of the fact that they converge and are identical at the point where the stimulus appears. The stimulus for the exteyoceptors [1] constitutes a relatively late and rather completely formulated phase of the psychological act. The stimulus for the interceptors [2] constitutes an earlier and less definitely formulated phase of behaviour. It often happens that a stimulus for the interoceptors is the first conscious presence of the unfinished behaviour which completes itself in a hunt for suitable stimulation of the exteroceptors. These latter stimuli in turn complete themselves as ordinary percepts into overt action and resulting satisfaction, or into a continued hunt for more stimuli. Two psychological acts may be declared to belong in the same category because of the similarity of the internal or external stimuli by which the several lines of unfinished behaviour converge or are identical.
A more important and fundamental basis of classification would be the possible identity of several types of behaviour at their energy-source. It may be possible to discover that the total energy of the organism, which is derived from its
( 27) metabolism, is divisible into energy-groups. It is not impossible to imagine that in one organism much of the energy may turn to digestive functions with resulting keen interest and satisfaction in food. In another organism a relatively smaller proportion of the energy which it accumulates is turned into this direction. There may well be individual differences in the division of the total energy of the organism into the several groups which constitute the source of its life-impulses. In a similar manner organisms of the same species may differ in the relative proportion of their total energy which normally goes into the sex functions. In the human it is also conceivable that there are individual differences in the proportions of energy which normally seek expression in aggressive and self-assertive behaviour, in sex life, in digestion, in locomotion, in gregarious conduct, and so on. It may well be that the different behaviour of the prize-fighter and the scholar converge as identical in that early phase of their conduct in which both seek social approval. Both may be so absorbed in the immediate detail of what they are doing that they do not consciously realize the identity of the source of their labours.
It is in these energy-sources of conduct that we shall find the distinctions between instincts. Instincts can never be defined in terms of the stimuli by which we happen to express ourselves ; nor can they ever be defined in terms of particular behaviour on particular occasions. The futility of the instinct category in Psychology inheres in the fact that we have been looking for a specific stimulus on which to attach a specific instinctive response. The only point in the great variety of behaviour at which the
( 28) psychological acts belonging to an instinct are identical is at the energy-source.
If, instead of proceeding from the overt act toward the mental and the unconscious antecedents, we follow the psychological acts into their consequences, we find still additional points at which they may converge. Two psychological acts may be totally different, but they may conceivably have similar immediate consequences as objectively determined. Such a fact would be a legitimate basis of classification.
Still another basis for classifying actions together would be in the degree to which they may be substituted for each other with equal satisfaction to the actor. This is one of the most useful explanatory devices in psychology.
2. STAGES OF THE PSYCHOLOGICAL ACT
I have listed a number of stages in the development of psychological acts in which they may be identical or similar. If we start with action at its source and follow the stages through which it becomes formulated into conduct, and the consequent satisfactions, we shall have a table as follows :
(a) Energy-source
(b) Lowered threshold for stimuli
(c) Deliberate ideation
(d) The internal stimulus
(e) Imaginal hunt for external stimuli
(f) Overt hunt for external stimuli
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(g) The external stimulus
(h) The consummatory overt act
(i) Overt consequences of the act
(k) Satisfaction to the actor and quiescence at the energy-source
Lowered threshold for stimuli.— When an instinct condition is in a state of dissatisfaction there results a lowered threshold for relevant stimuli long before the appearance of conscious need, desire, or purpose. At five o'clock in the afternoon we are normally more easily tempted by the smell of a good steak than immediately after lunch, but in the absence of the external stimulus we may be entirely unaware of the lowered sensory and interest threshold. The instinct condition has by its lowered threshold already started to
( 30) determine the ultimate behaviour before any conscious or external indices appear. The behaviour is already on its course of formulation before the internal or external stimulus appears.
Deliberate ideation.— In the instinct condition of a dissatisfaction which has not yet become sufficiently acute to be conscious in sensory form, and in which the actor is not himself aware of the lowered interest threshold, the expected behaviour appears in imaginal form. Biologically the purpose of ideation is to prepare for action. The actor himself may not be aware of the fact that his thinking has its source in some state of incompleteness or dissatisfaction in the physical or social self. Since the need is not urgent or explicitly conscious, the actor's thinking is correspondingly calm and deliberate.
The internal stimulus is parallel to the stage of deliberate ideation in the formulation of behaviour, but it represents in those instinct conditions, where it normally takes part, a more definitely specified form of the behaviour than the ideation which precedes or accompanies it.
Imaginal hunt for the external stimulus represents a later and more complete formulation of behaviour than the free-moving, purposeless thought, and its relatives in internal stimuli. At this stage of the definition of conduct we have the expected experience in conscious form, and it has taken sufficient definition to be introspectively recognized as purposive. It is in reality an imaginal hunt for those suitable environmental stimuli which, if found, lead to consummatory action. It is purposive imaginal preparation for expected experience. Expected conduct is now beginning to take
(31) sufficient cognitive form to be the subject of imaginal trial-and-error choice. This is realistic thinking which is purposive as contrasted with autistic thinking, which is less definitely purposive. Both forms of thinking are driven by instinct conditions.
Overt hunt for external stimuli is merely carrying the purposive thinking into action in the hope of finding the imaginally expected stimuli. These overt actions may be directed immediately toward the significant stimulus, or they may be random in the nature of overt trial and error. It happens not infrequently that an instinct condition leads to overt random search without any conscious purpose, and without any definite conscious realization of the nature of the satisfaction that is sought.
The external stimulus represents a rather late stage in the formulation of behaviour. The psychological act is almost completed at the appearance of the external stimulus. The meaning of the stimulus is the expected satisfaction of the instinct condition for which the organism is ready. Many of the external stimuli are consciously sought, hunted for. The external stimuli which appear suddenly, such as danger signals, have as their meaning the maintenance of bodily integrity, a condition which by the mere fact of living, the organism is in constant readiness to maintain.
The consummatory overt act is the terminal of what I have called the psychological act.
The overt consequences of the act are inmost cases practically parallel with the consummatory act and with the satisfactions to the actor.
The satisfaction to the actor consists in quiescence at the
(32) energy-source. It should be noted that the beginning of this sequence and the end of it are identical in character. Behaviour starts in the instinct condition, and it terminates in the satisfied instinct condition. It is in this sense that we can speak of a reflex circuit rather than the reflex arc. We have traced the psychological sequence by which behaviour is formed. The mental antecedents of behaviour constitute in fact behaviour in the process of being particularized.
