McFarland (1974) has compared these kinds of interactions among behavior systems with the “time-sharing” that occurs when multiple users share the same computer system.
A striking example of this sort of behavioral organization is the incubation system of certain species of birds. Broody hens sit on their eggs for about 3 weeks. Once or twice a day, the hen gets off the eggs for about 10 minutes. During this interval she eats, drinks, grooms, and defecates. The proportion of the 10 minutes spent eating will vary depending on the state of her hunger system, but even 24 hours of food deprivation does not change the pattern of leaving the eggs (Sherry et al. 1980).
Another type of mechanism for behavior change depends upon the reaction of an animal to discrepant feedback. A male Siamese fighting fish, for example, will not display as long to its mirror image as to another displaying male. This is because the behavior of the mirror image is always identical to the behavior of the subject, but identical responses are not part of the “species expectation” of responses to aggressive display (Bols 1977). These mechanisms, and undoubtedly many others, all interact to produce the infinite variety of sequences of behavior characteristic of the animal in its natural environment.
Human Emotion
Emotion is one of the consequences of activating various behavior mechanisms. But specifying the concept in more detail is problematic because there is no consensus about its definition. Books have been written on the subject (e.g., Ekman & Davidson 1994; Barrett & Russell 2015), and two major journals, Emotion and Emotion Review, publish studies on emotion. The term usually refers to certain subjective experiences called feelings, but observable features often accompany them. I have defined a feeling as the activation of a specific central behavior mechanism (Hogan 2015), but characterizing those behavior mechanisms that subserve emotion is as intractable as the concept of emotion itself. I think some insight into the problem can be gained by considering some of the views of William James (1890, vol. 2). Note that in reading these quotes from James, when he uses the term instinct, I would replace it with the term “behavior system.”
In speaking of the instincts it has been impossible to keep them separate from the emotional excitements which go with them. Objects of rage, love, fear, etc., not only prompt a man to outward deeds, but provoke characteristic alterations in his attitude and visage, and affect his breathing, circulation, and other organic functions in specific ways. When the outward deeds are inhibited, these latter emotional expressions still remain, and we read the anger in the face, though the blow may not be struck, and the fear betrays itself in voice and color, though one may suppress all other sign. Instinctive reactions and emotional expressions thus shade imperceptibly into each other. Every object that excites an instinct excites an emotion as well. Emotions, however, fall short of instincts, in that the emotional reaction usually terminates in the subject’s own body, whilst the instinctive reaction is apt to go farther and enter into practical relations with the exciting object.(p. 442)
He goes on to state his famous theory of emotion.
Our natural way of thinking about these coarser emotions [grief, fear, rage, love] is that the mental perception of some fact excites the mental affection called the emotion, and that this latter state of mind gives rise to the bodily expression. My theory, on the contrary, is that the bodily changes follow directly the perception of the exciting fact, and that our feeling of the same changes as they occur is the emotion.(p. 449)
In other words, when we meet a bear and run away, we are not running away because we are frightened; we are frightened because we are running away—fright is our perception of all the bodily changes that occur when we run away. This theory has been subject to much criticism to which I will return shortly. But first I will quote some more of James’ views.
Now the moment the genesis of an emotion is accounted for, as the arousal by an object of a lot of reflex acts which are forthwith felt, we immediately see why there is no limit to the number of possible different emotions which may exist, and why the emotions of different individuals may vary indefinitely, both as to their constitution and as to objects which call them forth…. such a question as “What is the ‘real’ or ‘typical’ expression of anger, or fear?” is seen to have no objective meaning at all. Instead of it we now have the question as to how any given ‘expression’ of anger or fear may have come to exist; and that is a real question of physiological mechanics on the one hand, and of history [evolution] on the other…(p. 454)
I have quoted from James so extensively because the ideas he expressed have continued to dominate studies of emotion from his time to the present. Historically, the idea that has been most discussed is his idea that emotion is the perception of the feedback one gets from bodily changes in response to some arousing situation. Everyone agrees that most emotional situations cause a multitude of visceral changes such as increases in heart rate, vasoconstriction, sweating, etc., all of which are caused by sympathetic nervous system action. However, Cannon (1927) challenged the notion that perception of these changes is the emotion for several reasons. He pointed out that the viscera are relatively insensitive structures and that visceral changes are too slow to account for emotional feelings that occur demonstrably quicker. He also cited results of Marañon, who injected epinephrine, a sympathetic nervous system stimulant, into human subjects and asked them to describe their feelings. The results showed a clear distinction “between the perception of the peripheral phenomena of vegetative emotion (i.e., the bodily changes) and the psychical emotion proper, which does not exist and which permits the subjects to report on the vegetative syndrome with serenity, without true feeling” (tr. by Cannon 1927, p. 113).
Cannon also pointed out that the same visceral changes occur in very different emotional states as well as in nonemotional states. What distinguishes the different emotional states from each other? What is responsible for the “feeling” of each emotional state? James was aware of this problem, as we have seen, because he showed that there is no typical expression of each emotion. But James does list four “coarser” emotions and discusses a large number of “subtler” emotions, so presumably he thought that we can introspectively distinguish among them, perhaps on the basis of the nonorganic emotional expressions such as facial features or postures. Schachter and Singer (1962) proposed that the quality of an emotion is arrived at by a process of cognitive appraisal. In one of their experiments they injected epinephrine into human subjects. Some of the subjects were told what effects they might expect and others were not told anything about the effects. All subjects were then observed in the presence of a confederate of the experimenter who acted in either an elated or angry manner. The subjects were later asked about their emotional reactions. The informed subjects reported very little emotion (as also the subjects of Marañon); but the uninformed subjects did report emotional feelings, and the kind of emotion they felt tended to mimic that of the confederate. In other words, in precisely the same state of physiological arousal, emotional labels depended on the cognitive aspects of the situation.
Since 1962, there have been hundreds of studies on emotion. Gendron and Barrett (2009) review the history of scientific ideas about emotion and posit three major approaches to its study: basic emotion, appraisal, and psychological construction. The basic emotion approach has been a major focus of studies in “affective science,” as studies of emotion have come to be called. The goal of researchers in this area is to discover and characterize the basic emotions, which are considered to be inherent in our biological endowment. However, in spite of years of research, there is still no consensus about the identity of the basic emotions. Tracy and Randles (2011) recently reviewed four models of basic emotions proposed by four prominent researchers in the area (Ekman, Izard, Levenson, Panksepp). Their lists of basic emotions are somewhat similar (fear is included in all four lists, and sadness, anger, and disgust are included in three of the four lists), but there are still many differences and many problems of definition of terms remain. Panksepp’s (2005) list is the most divergent from the other three, which probably reflects the fact that he bases his list on his analysis of “the neurodynamics of brain systems that generate instinctual emotional behaviors” in various mammalian species, whereas the others base their lists on experimental studies of human subjects.
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