Sympathy is the perception of, understanding of, and reaction to the distress or need of another life form. According to David Hume, this sympathetic concern is driven by a switch in viewpoint from a personal perspective to the perspective of another group or individual who is in need. Hume explained that this is the case because "the minds of all men are similar in their feelings and operations" and that "the motion of one communicates itself to the rest" so that as "affections readily pass from one person to another… they beget correspondent movements." Etymology The roots of the word sympathy are the Greek words sym, which means "together", and pathos, which refers to feeling or emotion. See sympathy § Etymology for more information. Distinctions between sympathy and related concepts The related word empathy is often used interchangeably with sympathy; with empathy meaning one is able to feel another's feelings. Compassion and pity are also related concepts. Causes Prerequisites for feeling sympathy include: attention to a subject, believing that subject is in a state of need, and . To feel sympathy for a person or group, you must first pay attention to them. Distractions severely limit the ability to produce strong affective responses. When not distracted, people can attend to and respond to a variety of emotional subjects and experiences. Attention facilitates the experience of sympathy; without giving undivided attention sympathy cannot be experienced in many situations. The perceived need of an individual/group elicits sympathy. Different states of need (such as perceived vulnerability or pain) require different sorts of human reactions, including those that range from attention to sympathy. A person with cancer might draw a stronger feeling of sympathy than a person with a cold. Opinions about human deservingness, interdependence, and vulnerability motivate sympathy. A person who seems "deserving" of aid is more likely to be helped. A belief in human interdependence fuels sympathetic behavior. Sympathy is also believed to be based on the principle of the powerful helping the vulnerable (young, elderly, sick). This desire to help the vulnerable has been suggested to stem from paternalistic motives to protect and aid children and the weak. In this theory, people help other people in general by generalizing the maternal/paternal instincts to care for their own children or family. Individual moods, previous experiences, social connections, novelty, salience, and spatial proximity also influence the experience of sympathy. Individuals experiencing positive mood