Running Head: EXTENDED SELF: MY OBJECTS AND MPFC Extended Self: Spontaneous Activation of Medial Prefrontal Cortex by Objects that are “Mine”

The concept of extended self refers to the idea that people incorporate self-relevant others or objects into one's sense of self. Initial neural support for the notion of extended self was provided by fMRI evidence that medial prefrontal cortex (MPFC) showed greater activation while people imagined objects belonging to them compared to someone else (Kim & Johnson, 2012). The current study investigated whether self-associated objects (i.e., " mine ") subsequently engage MPFC spontaneously when a task does not require explicit self-referential judgments. During fMRI scanning, participants detected " oddballs " (objects with a specific frame color) intermixed with objects participants had previously imagined belonging to them or to someone else and previously unseen non-oddball objects. There was greater activity in MPFC and posterior cingulate cortex (PCC) for those " self-owned " objects that participants were more successful at imagining owning compared to " other-owned " objects. In addition, change in object preference following the ownership manipulation (a mere ownership effect) was predicted by activity in MPFC. Overall, these results provide neural evidence for the idea that personally relevant external stimuli may be incorporated into one's sense of self. 3 A central feature of human experience is a sense of 'self' that provides stability and continuity to the flow of subjective experience across space and time (Damasio, 1999; Neisser, 1988). As noted by William James, each individual inevitably makes the " great splitting of the whole world into two halves " involving not only the distinction between parts unambiguously belonging to oneself ('me') from the immediate external environment ('not me') but also the distinction between other aspects of one's experiences that bear relevance to oneself ('mine') from those with no or minimal self-relevance ('not mine') (James, 1890/1983, p. 289). That is, one's sense of self can extend beyond the sense of body ownership and agency (minimal self: Gallagher, 2000), for example, when self-relevant people (Aron et al., 1991) or objects (Belk, 1988; Wicklund & Gollwitzer, 1982) are incorporated into one's sense of self. In particular, Belk (1988) suggested that one's possessions can be considered part of one's extended self. The early development of an understanding of ownership and strong self-object associations provides support for the importance of ownership in human social-cognitive functioning (Fasig, 2000; Ross, 1996). Acquiring ownership of an object triggers a range of cognitive and affective effects. Even transient, imagined ownership produces a memorial advantage (self-reference effect; Cunningham et …