Introducing IOS11 as an extended interactive version of the ‘Inclusion of Other in the Self’ scale to estimate relationship closeness

Baader, Malte; Starmer, Chris; Tufano, Fabio; Gächter, Simon

Abstract

The study of relationship closeness has a long history in psychology and is currently expanding across the social sciences, including economics. Estimating relationship closeness requires appropriate tools. Here, we introduce and test a tool for estimating relationship closeness: ‘IOS11’. The IOS11 scale has an 11-point response scale and is a refinement of the widely used Inclusion-of-Other-in-the-Self scale. Our tool has three key features. First, the IOS11 scale is easy to understand and administer. Second, we provide a portable, interactive interface for the IOS11 scale, which can be used in lab and online studies. Third, and crucially, based on within-participant correlations of 751 individuals, we demonstrate strong validity of the IOS11 scale in terms of representing features of relationships captured by a range of more complex survey instruments. Based on these correlations we find that the IOS11 scale outperforms the IOS scale and performs as well as the related Oneness scale.

Citation

Baader, M., Starmer, C., Tufano, F., & Gächter, S. (2024). Introducing IOS11 as an extended interactive version of the ‘Inclusion of Other in the Self’ scale to estimate relationship closeness. Scientific Reports, 14(1), Article 8901. https://doi.org/10.1038/s41598-024-58042-6

• Journal Article Type: Article
• Acceptance Date: Mar 25, 2024
• Online Publication Date: Apr 17, 2024
• Publication Date: Apr 17, 2024
• Deposit Date: Apr 19, 2024
• Publicly Available Date: Apr 19, 2024
• Journal: Scientific Reports
• Electronic ISSN: 2045-2322
• Publisher: Nature Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 14
• Issue: 1
• Article Number: 8901
• DOI: https://doi.org/10.1038/s41598-024-58042-6
• Keywords: Human behaviour; Psychology
• Public URL: https://nottingham-repository.worktribe.com/output/33837144
• Additional Information: Received: 27 November 2023; Accepted: 25 March 2024; First Online: 17 April 2024; : The authors declare no competing interests.