Fusion refers to the sense that a construct is integrated into the self-concept. When a person feels fused with a construct, there is a perceived "oneness" with the construct, and as a result, the construct is treated as an extension of the self. This concept of fusion has been explored across a wide range of constructs and within a number of subfields in psychology. The goal of this article is to provide a comprehensive view of the fusion process and to connect these disparate areas of literature underneath a single unifying theme. Specifically, we focus on five constructs that researchers have explored in terms of fusion: objects, thoughts, goals, significant others, and groups. In our review, we discuss the ways that fusion is typically measured and highlight the consequences that occur as a result of such fusion. We conclude by highlighting questions that remain unanswered and suggest potential areas of future development.Fusion refers to the sense that a construct is integrated into the self-concept. Combat veterans are good examples of individuals who fuse with those around them and their roles in combat. Their self-concept changes to include those roles and their comrades-in-arms. This fusion likely serves as a major source of motivation and morale and is likely beneficial to their survival. However, upon returning to civilian life, this fusion can make adjusting difficult. Without these parts of their self-concept, they may feel as if they have lost something of themselves. For other individuals, objects, thoughts, goals, and other people can become a part of their self-concept. This fusion with the self-concept can have a significant impact on their lives.The idea that a construct can become integrated, or fused, with the self-concept is not new to psychology. James (1890, p. 291) was one of the first to point out this integration of outside constructs with the self, stating, "It is clear that between what a man calls me and what he simply calls mine the line is difficult to draw." Similarly, Aron and Aron (1997) suggested that the more one perceives a construct as fused, the more the construct is included within the knowledge structures of the self. This means that when a particular construct is highly fused, it no longer is something the person simply does, wears, or thinks. Rather, it is a part of who they are. Thus, a person low in fusion with running "goes running," but a person high in fusion with running "is a runner." What constructs can become fused within the self-concept? Most obvious are constructs pertaining to our physical body (e.g., skin and fingers; see Allport, 1955;Belk, 1988;Burris & Rempel, 2004;James, 1890;Prelinger, 1959). We perceive parts of our body as pieces of our self. If we lose a finger or a limb, we lose a part of our self, but the overall self is still present. Extensions of the physical body can also be perceived as parts of our self, including our shadows or the warmth produced by our bodies (Horwicz, 1872). But fusion extends far beyond our physical form.In t...
