Emotion

Emotions are physical and mental states brought on by neurophysiological changes, variously associated with thoughts, feelings, behavioral responses, and a degree of pleasure or displeasure. There is no scientific consensus on a definition. Emotions are often intertwined with mood, temperament, personality, disposition, or creativity.

Research on emotion has increased over the past two decades, with many fields contributing, including psychology, medicine, history, sociology of emotions, computer science and philosophy. The numerous attempts to explain the origin, function, and other aspects of emotions have fostered intense research on this topic. Theorizing about the evolutionary origin and possible purpose of emotion dates back to Charles Darwin. Current areas of research include the neuroscience of emotion, using tools like PET and fMRI scans to study the affective picture processes in the brain.

From a mechanistic perspective, emotions can be defined as "a positive or negative experience that is associated with a particular pattern of physiological activity". Emotions are complex, involving multiple different components, such as subjective experience, cognitive processes, expressive behavior, psychophysiological changes, and instrumental behavior. At one time, academics attempted to identify the emotion with one of the components: William James with a subjective experience, behaviorists with instrumental behavior, psychophysiologists with physiological changes, and so on. More recently, emotion has been said to consist of all the components. The different components of emotion are categorized somewhat differently depending on the academic discipline. In psychology and philosophy, emotion typically includes a subjective, conscious experience characterized primarily by psychophysiological expressions, biological reactions, and mental states. A similar multi-componential description of emotion is found in sociology. For example, Peggy Thoits described emotions as involving physiological components, cultural or emotional labels (anger, surprise, etc.), expressive body actions, and the appraisal of situations and contexts. Cognitive processes, like reasoning and decision-making, are often regarded as separate from emotional processes, making a division between "thinking" and "feeling". However, not all theories of emotion regard this separation as valid.

Nowadays, most research into emotions in the clinical and well-being context focuses on emotion dynamics in daily life, predominantly the intensity of specific emotions and their variability, instability, inertia, and differentiation, as well as whether and how emotions augment or blunt each other over time and differences in these dynamics between people and along the lifespan.

The word "emotion" dates back to 1579, when it was adapted from the French word émouvoir, which means "to stir up". The term emotion was introduced into academic discussion as a catch-all term to passions, sentiments and affections. The word "emotion" was coined in the early 1800s by Thomas Brown and it is around the 1830s that the modern concept of emotion first emerged for the English language. "No one felt emotions before about 1830. Instead they felt other things – 'passions', 'accidents of the soul', 'moral sentiments' – and explained them very differently from how we understand emotions today."

Some cross-cultural studies indicate that the categorization of "emotion" and classification of basic emotions such as "anger" and "sadness" are not universal and that the boundaries and domains of these concepts are categorized differently by all cultures. However, others argue that there are some universal bases of emotions (see Section 6.1). In psychiatry and psychology, an inability to express or perceive emotion is sometimes referred to as alexithymia.

Human nature and the accompanying bodily sensations have always been part of the interests of thinkers and philosophers. Far more extensively, this has also been of great interest to both Western and Eastern societies. Emotional states have been associated with the divine and with the enlightenment of the human mind and body. The ever-changing actions of individuals and their mood variations have been of great importance to most of the Western philosophers (including Aristotle, Plato, Descartes, Aquinas, and Hobbes), leading them to propose extensive theories—often competing theories—that sought to explain emotion and the accompanying motivators of human action, as well as its consequences.

In the Age of Enlightenment, Scottish thinker David Hume proposed a revolutionary argument that sought to explain the main motivators of human action and conduct. He proposed that actions are motivated by "fears, desires, and passions". As he wrote in his book A Treatise of Human Nature (1773): "Reason alone can never be a motive to any action of the will… it can never oppose passion in the direction of the will… The reason is, and ought to be, the slave of the passions, and can never pretend to any other office than to serve and obey them". With these lines, Hume attempted to explain that reason and further action would be subject to the desires and experience of the self. Later thinkers would propose that actions and emotions are deeply interrelated with social, political, historical, and cultural aspects of reality that would also come to be associated with sophisticated neurological and physiological research on the brain and other parts of the physical body.