Emotions.

Emotions are biological states associated with the nervous system[1][2][3] brought on by neurophysiological changes variously associated with thoughts, feelings, behavioural responses, and a degree of pleasure or displeasure.[4][5] There is currently no scientific consensus on a definition. Emotions are often intertwined with mood, temperament, personality, disposition, creativity[6][7] and motivation.[8]

Research on emotion has increased significantly over the past two decades with many fields contributing including psychology, neuroscience, affective neuroscience, endocrinology, medicine, history, sociology of emotions, and computer science. The numerous theories that attempt to explain the origin, neurobiology, experience, and function of emotions have only fostered more intense research on this topic. Current areas of research in the concept of emotion include the development of materials that stimulate and elicit emotion. In addition, PET scans and fMRI scans help study the affective picture processes in the brain.[9]

From a purely mechanistic perspective, "Emotions can be defined as a positive or negative experience that is associated with a particular pattern of physiological activity." Emotions produce different physiological, behavioral and cognitive changes. The original role of emotions was to motivate adaptive behaviors that in the past would have contributed to the passing on of genes through survival, reproduction, and kin selection.[10][11]

In some theories, cognition is an important aspect of emotion. For those who act primarily on emotions, they may assume that they are not thinking, but mental processes involving cognition are still essential, particularly in the interpretation of events. For example, the realization of our believing that we are in a dangerous situation and the subsequent arousal of our body's nervous system (rapid heartbeat and breathing, sweating, muscle tension) is integral to the experience of our feeling afraid. Other theories, however, claim that emotion is separate from and can precede cognition. Consciously experiencing an emotion is exhibiting a mental representation of that emotion from a past or hypothetical experience, which is linked back to a content state of pleasure or displeasure.[12] The content states are established by verbal explanations of experiences, describing an internal state.[13]

Emotions are complex. According to some theories, they are states of feeling that result in physical and psychological changes that influence our behavior.[5] The physiology of emotion is closely linked to arousal of the nervous system with various states and strengths of arousal relating, apparently, to particular emotions. Emotion is also linked to behavioral tendency. Extroverted people are more likely to be social and express their emotions, while introverted people are more likely to be more socially withdrawn and conceal their emotions. Emotion is often the driving force behind motivation, positive or negative.[14] According to other theories, emotions are not causal forces but simply syndromes of components, which might include motivation, feeling, behavior, and physiological changes, but no one of these components is the emotion. Nor is the emotion an entity that causes these components.[15]