Abstract
Progress in emotions research requires understanding why debate about the general nature of emotions remains intractable. Much confusion arises from proposals that offer one of the four different kinds of biological explanation, without recognizing the need for other three. More arises from tacitly thinking of emotions as products of design, when they are actually organically complex products of natural selection. Finally, debate persists because of categorizing emotions by functions, instead of recognizing that each emotion was shaped by the adaptive challenges posed by a recurring situation. No general explanation of the kind usually sought for emotions exists, however progress is possible if we study emotions as organically complex partially differentiated constellations of changes that have been useful in certain situations.
Decades of work by scores of smart scientists leave us far from agreement on “a theory of emotion.” The current special section of Emotion Review is a fine attempt to move forward. It invites multiple perspectives, and asks specific questions, in an attempt to get closer to consensus. Are we nearly there? The diversity of these four perspectives suggests not. Now what?
Instead of just creating and comparing yet more theories of emotion, it is worth asking why agreement has been so elusive. As demonstrated by the four articles in this section, the problem is not lack of effort or sophistication. It is much deeper, and threefold. First, most theories of emotion address only one of the four different kinds of questions that need answers. Second, many theories of emotion are not about the whole, but only about one aspect of emotion. Finally, there is the assumption that emotion can be explained by a general theory.
Fifty years ago, Niko Tinbergen framed four questions that need to be answered to fully explain any biological trait (Nesse, 2013; Tinbergen, 1963). What is the mechanism? What is its ontology? What is its phylogeny? And, how have variations in the trait interacted with environments in ways that influenced fitness and thus helped to shape the trait? Tinbergen’s huge contribution was recognizing that answers to these questions are not alternative explanations, they are complementary essential parts of a complete explanation.
The article by Tracy (2014) answers the fourth question. It notes that emotions exist because they have given selective advantages when expressed in certain situations (Nesse, 1990). This is inescapably correct; only natural selection can explain complex biological traits whose expression is regulated. She proceeds to say that each emotion has a function. This is generally correct, but it could incorrectly imply that different emotions have different functions, while most serve multiple functions, such as communication and arousal, that are shared with other emotions. Differences among emotions are explained, not by different functions, but by the different adaptive challenges of the situations that shaped them. Thus, emotions are only somewhat differentiated from each other, a conclusion inconsistent with theories of emotions as distinct basic kinds, or positions on dimensions (Nesse & Ellsworth, 2009). Tracy also says that aspects of an emotion must each have a function. This too is a fair generalization, although some aspects are epiphenomena, such as turning white when frightened, while others are useful only in certain environments, some of which no longer exist.
The article by Moors (2014) addresses the question about mechanisms. It emphasizes those that regulate emotional expression based on an appraisal of the meaning of information for an individual’s ability to reach personal goals. Appraisal is important, but it is, as she notes, only one part of the larger mechanism that regulates emotional responses. Further investigation of how appraisal mechanisms work, and their neural underpinnings, is, as Moors suggests, important.
The article by Mesquita and Boiger (2014) argues that emotions are most often aroused by social situations, and that the interplay of social emotions and behavior in relationships leads to recursive causal chains of enormous complexity. This too is certainly correct, but it is only part of the picture; other kinds of situations also arouse emotions, as she notes. There is a great opportunity for exploring the phylogeny of social emotions, how they were shaped by social selection, and how they make possible kinds of relationships that are impossible for other species.
The article by Barrett (2014) is about the classification of emotions, and how these classifications, and our descriptions of them, influence the meaning and functions of emotions. Again, there is no need to argue with the thesis. It is not incompatible with the other perspectives, but it also is not well connected with them. For instance, the deep structure of emotions maps onto the situations that shaped them; it is this deep structure that interacts with social and other situations to give rise to the states that we observe, experience, and classify, using socially constructed understandings that change our experiences and behavior.
In short, each article says something true and important about emotion, but none is a theory about emotion in general. Each addresses one of Tinbergen’s four questions, at most, and each emphasizes one aspect of emotions at the expense of others.
A natural next step would seem to be to construct a comprehensive theory of emotion using all four questions, and focusing on the whole instead of the parts. It seems to me, however, that a general theory of emotion is neither necessary nor possible. Emotions have no essence that makes them susceptible to a general explanation. They are like physiological responses. No one seeks a general theory of physiology. Instead, scientists propose theories about the mechanisms, ontogenies, phylogenies, and functions of physiological responses. Efforts to create a general theory of emotion, are distracting from the work of creating specific theories about emotions—their mechanisms, ontogeny, phylogeny, and functional significance.
We already have many theories about emotions, but some are unappreciated because they are framed as general theories of emotion. Extracting them into a larger framework is an important project. However, the result will never fully satisfy the human lust for order and simplicity. The emotions were not designed, they were shaped by natural selection, so their structure is organically complex in ways not susceptible to simple categorization and description. Worse yet, substantial genetic variation that influences emotion mechanisms interacts with vast developmental and cultural variation to result in dramatic variations in emotional responses among individuals. Just as there is no such thing as “the normal genome,” there is no such thing as “the normal emotional system.” Giving up the search for the essence of emotion, and the notion that there is one normal emotion regulation mechanism, should not arouse hopelessness. Instead, it should arouse relief at giving up an impossible quest, and excitement about moving on to address the several questions whose answers will explain emotions.