title: Measuring the Closeness of Relationships: A Comprehensive Evaluation of the 'Inclusion of the Other in the Self' Scale.
abstract: Understanding the nature and influence of social relationships is of increasing interest to behavioral economists, and behavioral scientists more generally. In turn, this creates a need for tractable, and reliable, tools for measuring fundamental aspects of social relationships. We provide a comprehensive evaluation of the 'Inclusion of the Other in the Self' (IOS) Scale, a handy pictorial tool for measuring the subjectively perceived closeness of a relationship. The tool is highly portable, very easy for subjects to understand and takes less than 1 minute to administer. Across our three online studies with a diverse adult population (n = 772) we show that six different scales designed to measure relationship closeness are all highly significantly positively correlated with the IOS Scale. We then conduct a Principal Component Analysis to construct an Index of Relationship Closeness and find that it correlates very strongly (ρ = 85) with the IOS Scale. We conclude that the IOS Scale is a psychologically meaningful and highly reliable measure of the subjective closeness of relationships.
authors.affiliation: Centre for Decision Research and Experimental Economics, School of Economics, University of Nottingham, University Park, Nottingham, United Kingdom; CESifo Network, Munich, Germany; IZA Network, Bonn, Germany.
authors.forename: Simon
authors.initials: S
authors.lastname: Gächter
authors.affiliation: Centre for Decision Research and Experimental Economics, School of Economics, University of Nottingham, University Park, Nottingham, United Kingdom.
authors.forename: Chris
authors.initials: C
authors.lastname: Starmer
authors.affiliation: Centre for Decision Research and Experimental Economics, School of Economics, University of Nottingham, University Park, Nottingham, United Kingdom.
authors.forename: Fabio
authors.initials: F
authors.lastname: Tufano
mesh_terms: D000328:Adult; D060909:Economics, Behavioral; D004532:Ego; D005260:Female; D006801:Humans; D007398:Interpersonal Relations; D008297:Male