Figure 4.

The Friend-Body-Swap Illusion Also Reconfigured the Multidimensional Structure of Self-Concept and Made It More Similar to the Structure of Friend-Concept

(A) A schematic illustration of “structural similarity.” Graphs represent ratings of five example personality traits provided with regard to the self (red) and the friend (green). Pairs of traits that are closer to each other were rated more similarly than traits that are farther apart. Structural similarity corresponds to resemblance between shapes of the whole graphs rather than between individual traits.

(B) For each participant in each condition, we calculated two distance matrixes: one between friend ratings (left) and the other between self-ratings (right). Both matrixes are based on the same traits (i.e., only the ones that were presented during a given condition). These unique “barcodes” of the participant's beliefs about one's own and friend's personalities correspond to distances between the ratings of each trait in relation to all other traits. For group analyses, we calculated a correlation between the self-matrix and the friend-matrix for each participant in each condition.

(C) Data from the syncF and asyncF conditions from a representative participant who experienced a strong friend-body-swap illusion (I1-ownership-ratings: syncF - asyncF = 4). For display purposes, trait adjectives are sorted according to the hierarchical clustering algorithm applied to friend ratings (“template”). Without sorting, the heatmaps in syncF would have looked like (B) (same data). Importantly, in the syncF condition, the main clusters of similar (low distance; red) and dissimilar (high distance; blue) ratings are largely preserved between the self- and friend-matrixes, resulting in high overall self-to-friend similarity (Spearman's rho = 0.54). In contrast, in the asyncF condition, the structure of clusters is very different between the self- and friend-matrixes, resulting in low overall self-to-friend similarity (Spearman's rho = 0.12).

(D) At the group level, structural similarity between self- and friend-ratings was higher in the syncF than in the asyncF condition (N = 65; means ± SE).

(E and F) The stronger the illusion of owning the friend's body—as measured by the illusion questionnaire ownership ratings (E) and threat-evoked skin conductance responses (F)—the greater the structural similarity between ratings of one's own and the friend's personalities in the syncF condition.