Evolution, Emotions, and Emotional Disorders

Evolution, Emotions, and Emotional Disorders

Fatima Alvi

In an attempt to condense the abstract nature of emotions into a definable entity suitable for objective study, researchers have traditionally limited their view of emotions to depend on aspects like physiology, experience, and facial expression (Nesse & Ellsworth, 2009). These generic categories have failed to achieve a satisfying definition, as has been well noted, that encompasses the complexity observed in emotional responses. Examining human emotion from an evolutionary standpoint provides a broader base of understanding that attains a more workable definition by asking the question of “how” rather than “what” – how did emotions evolve into their present forms? How, by various factors throughout evolutionary history, were our current emotional habits selected for? In the paper Evolution, Emotions, and Emotional Disorders, by Randolph Nesse and Phoebe Ellsworth, the authors explore the evolutionary background behind emotion, what it implies in the field of emotions research, and how that information provides insight into the realm of emotional disorders.

A key point in the evolutionary study of emotions is to emphasize that “emotions would not exist unless they were useful,” (Nesse & Ellsworth, 2009). Declaring a certain emotion “useful” in a situation appears more subjective than would seem constructive for our purposes, but the fact that the usefulness of an emotional response shifts between individuals helps to explain the sustained diversity of sentiments expressed by humans.  The complexity of emotion also stresses that no single event or circumstance necessarily elicits a single particular response.  Rather, an emotional reaction is a composite, organized response resulting from the coordination of multiple processes to engage with the adaptive tasks presented by a situation (Nesse & Ellsworth, 2009). Thus, emotions can be explained as states that confer fitness advantages in situations repeated throughout evolutionary history. While attempts have been made by numerous researchers to categorize emotions into distinct, finite divisions, this evolutionary view blurs the boundaries between sentiments to yield more personal responses with overlapping functions and qualities. To truly understand an individual’s emotions, argue the authors, one must not only observe the “objective situation,” but must also reflect on how that individual appraises that situation, or perceives and processes it. Appraisal is based on both genes and personal experience (Nesse & Ellsworth, 2009).

An evolutionary study of emotional disorders can reveal much about the susceptibilities that selection has produced. By understanding the reasoning for the existence of normal emotions (that, when severely expressed, are considered disorders) we may find a deeper and more thorough comprehension of the mechanisms at work. Viewing emotional disorders from their adaptive origins can be useful for determining medicinal therapies as well. If an emotion (or emotional disorder) is an adaptation, then “no single genetic polymorphism accounts for more than a small percentage of [its] variance” – and thus, multiple “locations” exist at which the mediating system for a disorder can be disrupted (Nesse & Ellsworth, 2009). In so complex a field as emotions, I feel that an evolutionary explanation – which considers the advantages and reasoning behind the development and continuance of our diverse range of emotions – is preferable to and more useful than a narrow, proximate definition that attempts to confine the inherent intricacies of emotion into convenient but limited classifications.

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Nesse, R., & Ellsworth, P. (2009) Evolution, Emotions, and Emotional Disorders. American Psychologist, 64(2), 129-139.