seen as the presence of companions to engage in shared social activities. Formerly, it was also referred to as "esteem support" or "appraisal support," but these have since developed into alternative forms of support under the name "appraisal support" along with normative and instrumental support. Researchers also commonly make a distinction between perceived and received support. Perceived support refers to a recipient's subjective judgment that providers will offer (or have offered) effective help during times of need. Received support (also called enacted support) refers to specific supportive actions (e.g., advice or reassurance) offered by providers during times of need. Furthermore, social support can be measured in terms of structural support or functional support. Structural support (also called social integration) refers to the extent to which a recipient is connected within a social network, like the number of social ties or how integrated a person is within his or her social network. Family relationships, friends, and membership in clubs and organizations contribute to social integration. Functional support looks at the specific functions that members in this social network can provide, such as the emotional, instrumental, informational, and companionship support listed above. Data suggests that emotional support may play a more significant role in protecting individuals from the deleterious effects of stress than structural means of support, such as social involvement or activity. These different types of social support have different patterns of correlations with health, personality, and personal relationships. For example, perceived support is consistently linked to better mental health whereas received support and social integration are not. In fact, research indicates that perceived social support that is untapped can be more effective and beneficial than utilized social support. Some have suggested that invisible support, a form of support where the person has support without his or her awareness, may be the most beneficial. This view has been complicated, however, by more recent research suggesting the effects of invisible social support–as with visible support–are moderated by provider, recipient, and contextual factors such as recipients' perceptions of providers' responsiveness to their needs, or the quality of the relationship between the support provider and recipient. Sources Social support can come from a variety of sources, including (but not limited to): family, friends, romantic partners, pets, community ties, and coworkers. Sources of support can be natural (e.g., family and friends) or more formal (e.g., mental health specialists or community organizations). The source of the