Inclusion of Other in the Self Scale (IOS)

Social psychologist Arthur Aron and colleagues (1992) developed the single-item Inclusion of Other in the Self (IOS) scale to measure how close the respondent feels with another person or group. The IOS has been given to respondents as young as five years old (Cameron, 2006), as well as to teens and adults. It has also been used with respondents living on a low income and previously incarcerated respondents (Folk et al., 2016; Mashek, Cannaday, & Tangney, 2007). Respondents see seven pairs of circles that range from just touching to almost completely overlapping. One circle in each pair is labeled “self,” and the second circle is labeled “other.” Respondents choose one of the seven pairs to answer the question, “Which picture best describes your relationship with [this person/group]?” Researchers indicate what person or group the “other” circle stands for (e.g., “your romantic partner,” “your parents,” “your community,” etc.). 1 = no overlap; 2 = little overlap; 3 = some overlap; 4 = equal overlap; 5 = strong overlap; 6 = very strong overlap; 7 = most overlap.