For most of recorded time, at least in the Western world, the vast majority of people, including scientists, regarded emotion as the antithesis of reason or rational thought. Emotion was also associated with being female—the other gender being ruled by logic. Furthermore, emotion was seen as a disruptive force in life, to be harnessed and controlled. Because of these implicit assumptions and stereotypes, emotion was not regarded as a fit topic for scientific research until Charles Darwin began to record the emotional expressions of animals and humans late in the nineteenth century and noted their evolutionary significance. His works introduced the idea that there were certain basic emotions and that emotions served adaptive functions—that is, that they were essential to survival rather than something that interfered with it. These basic emotions include anger, fear, sadness, disgust, shame, contempt, joy, interest, and surprise.
In the early part of the twentieth century, the behaviorist John Watson began using laboratory studies to examine the basic or fundamental emotions in human infants. Although he believed, along with Darwin, that certain emotions were innate, his studies showed that emotional behaviors were responses that could become "conditioned" and thus shape the personality of the child. However, his work did little to redeem the value of emotions in the mind of the public because he shared the view of most of his contemporaries that emotions caused pathological problems and needed to be constrained. In fact, in his popular childrearing guide of 1928, Psychological Care of the Infant and Child, he urged parents to strictly control their displays of affection toward their children and to engage in behaviors designed to ensure that children would dampen or suppress their emotions.
After a small flurry of research inspired by Watson's work, the field lay relatively dormant until the late 1970s. At this time, the theoretical contributions of Silvan Tomkins, Carroll Izard, Paul Ekman, and Robert Plutchik sparked a new wave of research on the emotions. These theories stressed the unique motivational, expressive, physiological, neurological, and feeling states of the basic emotions. They also repeated and amplified Darwin's notion that emotions are fundamentally adaptive, though of course certain conditions could lead to more problematic behaviors such as depression or anxiety disorder. The new surge of research inspired by these theories led to fresh insights on the role of emotion and moods on cognition, memory, personality, and interpersonal process; there was also a good deal of research on how emotional expressions of infants and children changed over time and how children learned to talk about their emotions.
Research on emotional development in adulthood and aging accumulated more slowly. In some of the early studies before the 1980s, the general impression of both the lay public and developmental psychologists was that aging was accompanied by a blunting of the emotions; people also thought that there was a drift toward negative affect over the adult years. However, this impression was based largely on studies of institutionalized persons and therefore hardly representative of the population at large, since, both then, as well as presently, only about 5 percent of the older population live in nursing homes.
Work on affect and aging that began in the 1980s took an entirely different approach. It started to examine emotion as a life course process, and the work on older adults at the upper end of the life span was based on persons living independent lives in their own communities. By the end of the twentieth century, there was a substantial corpus of theory as well as research mapping continuities and changes in emotion over the adult life course. The key figures in the field include Laura Carstensen, Caroll Izard, Gisela Labouvie-Vief, Powell Lawton, Carol Malatesta Magai, and Richard Schulz. The bulk of this literature has centered on issues of continuity and change in physiological patterns, expressive behavior, feeling states, emotion regulation, and emotion traits.