section_path: Notable theorists
section_name: Notable theorists
paragraph_text: Notable theorists
  
  In the late 19th century, the most influential theorists were William James (1842–1910) and Carl Lange (1834–1900). James was an American psychologist and philosopher who wrote about educational psychology, psychology of religious experience/mysticism, and the philosophy of pragmatism. Lange was a Danish physician and psychologist. Working independently, they developed the James–Lange theory, a hypothesis on the origin and nature of emotions. The theory states that within human beings, as a response to experiences in the world, the autonomic nervous system creates physiological events such as muscular tension, a rise in heart rate, perspiration, and dryness of the mouth. Emotions, then, are feelings which come about as a result of these physiological changes, rather than being their cause.
  
  Silvan Tomkins (1911–1991) developed the affect theory and script theory. The affect theory introduced the concept of basic emotions, and was based on the idea that the dominance of the emotion, which he called the affected system, was the motivating force in human life.
  
  Some of the most influential deceased theorists on emotion from the 20th century include Magda B. Arnold (1903–2002), an American psychologist who developed the appraisal theory of emotions; Richard Lazarus (1922–2002), an American psychologist who specialized in emotion and stress, especially in relation to cognition; Herbert A. Simon (1916–2001), who included emotions into decision making and artificial intelligence; Robert Plutchik (1928–2006), an American psychologist who developed a psychoevolutionary theory of emotion; Robert Zajonc (1923–2008) a Polish–American social psychologist who specialized in social and cognitive processes such as social facilitation; Robert C. Solomon (1942–2007), an American philosopher who contributed to the theories on the philosophy of emotions with books such as What Is An Emotion?: Classic and Contemporary Readings (2003); Peter Goldie (1946–2011), a British philosopher who specialized in ethics, aesthetics, emotion, mood and character; Nico Frijda (1927–2015), a Dutch psychologist who advanced the theory that human emotions serve to promote a tendency to undertake actions that are appropriate in the circumstances, detailed in his book The Emotions (1986); Jaak Panksepp (1943–2017), an Estonian-born American psychologist, psychobiologist, neuroscientist and pioneer in affective neuroscience; John T. Cacioppo (1951–2018), one of the founding fathers of social neuroscience; George Mandler (1924–2016), an American psychologist who wrote influential books on cognition and emotion.
  
  Influential theorists who are still active include the following psychologists, neurologists, philosophers, and sociologists: