Identity is the qualities, beliefs, personality traits, appearance, and/or expressions that characterize a person or group. In sociology, emphasis is placed on collective identity, in which an individual's identity is strongly associated with role-behavior or the collection of group memberships that define them. According to Peter Burke, "Identities tell us who we are and they announce to others who we are." Identities subsequently guide behavior, leading "fathers" to behave like "fathers" and "nurses" to act like "nurses." In psychology, the term "identity" is most commonly used to describe personal identity, or the distinctive qualities or traits that make an individual unique. Identities are strongly associated with self-concept, self-image (one's mental model of oneself), self-esteem, and individuality. Individuals' identities are situated, but also contextual, situationally adaptive and changing. Despite their fluid character, identities often feel as if they are stable ubiquitous categories defining an individual, because of their grounding in the sense of personal identity (the sense of being a continuous and persistent self). In psychology Erik Erikson (1902–1994) became one of the earliest psychologists to take an explicit interest in identity. An essential feature of Erikson's theory of psychosocial development was the idea of the ego identity (often referred to as the self), which is described as an individual's personal sense of continuity. He suggested that people can attain this feeling throughout their lives as they develop and is meant to be an ongoing process. The ego-identity consists of two main features: one's personal characteristics and development, and the culmination of social and cultural factors and roles that impact one's identity. In Erikson's theory, he describes eight distinct stages across the lifespan that are each characterized by a conflict between the inner, personal world and the outer, social world of an individual. Erikson identified the conflict of identity as occurring primarily during adolescence and described potential outcomes that depend on how one deals with this conflict. Those who do not manage a resynthesis of childhood identifications are seen as being in a state of 'identity diffusion' whereas those who retain their given identities unquestioned have 'foreclosed' identities. On some readings of Erikson, the development of a strong ego identity, along with the proper integration into a stable society and culture, lead to a stronger sense of identity in general. Accordingly, a deficiency in either of these factors may increase the chance of an identity crisis or confusion. The "Neo-Eriksonian" identity