Etymology and definitions

The English word 'emotion' is derived from the French émotion and émouvoir. This is based on the Latin emovere, where e- (variant of ex-) means 'out' and movere means 'move'. The related term "motivation" is also derived from movere. Emotions can be divided between 'cognitive' theories of emotions and 'non-cognitive' theories of emotions; or instinctual emotions (from the amgdala), and cognitive emotions (from the prefrontal cortex). Some psychologists divide emotions into basic and complex categories, where base emotions lead to more complex ones. Emotions can be categorized by its duration. Some emotions occur over a period of seconds (e.g. surprise) where others can last years (e.g. love). No definitive taxonomy exists.

A related distinction is between the emotion and the results of the emotion, principally behaviours and emotional expressions. People often behave in certain ways as a direct result of their emotional state, such as crying, fighting or fleeing. Yet again, if one can have the emotion without the corresponding behaviour then we may consider the behaviour not to be essential to the emotion. However some theorists such as the Dutch psychologist Nico Frijda hold a functionalist approach to emotions. Frijda argues that emotions have evolved for a particular function, such as to keep the subject safe. If the behaviours associated with an emotion are the determining factor for the very existence of that emotion then goal-directed behaviour should be regarded as essential to the emotion. Yet since we recognise that the behaviour need not necessarily occur, we can stipulate that emotions involve what are called 'action tendencies'. So for instance, fear involves the tendency to flee, which means that the probability that the subject will flee from a given situation is increased when he is undergoing fear.