Sympathy (from the Greek words syn "together" and pathos "feeling" which means "fellow-feeling") is the perception, understanding, and reaction to the distress or need of another life form. This empathic concern is driven by a switch in viewpoint, from a personal perspective to the perspective of another group or individual who is in need.
Empathy and sympathy are often used interchangeably. Sympathy is a feeling, but the two terms have distinct origins and meanings. Merriam Webster defines empathy as "the feeling that you understand and share another person's experiences and emotions" or "the ability to share someone else's feelings", as sympathy was defined by 18th century philosophers such as Adam Smith. Meanwhile, sympathy is defined as "the feeling that you care about and are sorry about someone else's trouble, grief, misfortune, etc.", "a feeling of support for something", or "a state in which different people share the same interests, opinions, goals, etc", but not necessarily the feeling that you share another person's emotions.
In order to get an experience of sympathy there are specific conditions that need to occur. These include: attention to a subject, believing that a person/group is in a state of need, and the specific characteristics of a given situation. An individual must first give his or her attention to a person/group. Distractions severely limit the ability to produce strong affective responses. Without distractions, people are able to attend to and respond to a variety of emotional subjects and experiences. Attention facilitates the experience of sympathy, and without giving undivided attention to many situations sympathy cannot be experienced.
The need of an individual/group is also considered to elicit sympathy. Varying states of need (such as perceived vulnerability or pain) require unique human reactions, ranging from attention to sympathy. A person with cancer might draw a stronger feeling of sympathy than a person with a cold. The conditions which sympathy is deemed as an appropriate response are organized into individual differences and situational differences.
The ways in which people think 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 the paternalistic nature of humans, in which they seek to protect and aid the children and the weak in their survival. People help others based on maternal/paternal instincts to care for their own children or family when they are in need.