Murky Waters: Is Self-Other Distinction a Clearly Defined Concept?

Murky Waters: Is Self-Other Distinction a Clearly Defined Concept?

Author: N. Bislimi

25.01.2025

Over the past 50 years, the growing research interest in the field of social cognition has led to phenomenal advances in understanding how humans process mental states — how we infer and interpret the thoughts, intentions, and emotions of others during social interactions. The ability to ascribe mental states to others enables individuals to adeptly navigate social challenges, thereby fostering more positive and meaningful interactions and interpersonal connections. Crucially, the advancements in this field have been increasingly applied to clinical psychology, offering valuable insights into understanding and addressing disorders marked by impairments in social interactions. However, before the scientific community can pat themselves on the back for a job well done, they must contend with the Achilles' heel of social-cognition research: a lack of conceptual clarity.

The inconsistency and lack of clarity in the terminology surrounding mental state attribution, which hinders both empirical and theoretical progress, is an open secret in the field. Ass.-Prof. François Quesque from the Université Paris Nanterre, has emerged as a leading figure in the efforts to tackle this conceptual ambiguity. Recently, he led a collaboration aimed at establishing a common lexicon for mental state attribution. This initiative resulted in the publication of the paper Defining Key Concepts for Mental State Attribution, drawing on insights from 451 experts from various disciplines, countries, and career stages (Quesque et al., 2024).

Together with Prof. Marcel Brass, Ass.-Prof. Quesque engaged with specialists to clarify and standardize key constructs in social cognition. Among the 18 identified constructs, self-other distinction (SOD) emerged as one of the two most consensual. Remarkably, 84% of the experts surveyed agreed on the definition of self-other distinction as "the process by which one distinguishes between self- and other-related representations (cognitive, affective, sensorimotor, etc.)" (Quesque et al., 2024).

Self-other distinction is essential for accurate social communication and understanding others' emotions, motives, and intentions. It enables individuals to maintain a clear boundary between their own mental states and those of others, thereby facilitating effective navigation of the social world. In other words, much like a water dam, SOD can be thought of as a semi-permeable barrier that keeps the mental states of the self and others separate, while still allowing for flexible movement between perspectives, similar to the flow of water between different areas. 

Intrigued by the consensus surrounding the definition of self-other distinction — an agreement seldom seen in the field of social cognition — we reached out to the paper's co-authors for their input. Univ.-Prof. Mag. Dr. Claus Lamm, Professor of Biological Psychology and the head of the SCAN-Unit at the University of Vienna, describes himself as an empathy researcher, a background that deeply informs his perspective on the topic. He acknowledges that the paper brings much-needed clarity to the field.

It was always pretty clear that SOD is not only clearly defined and definable, but even indispensable, as evidenced by its central role in both the theoretical and empirical literature on empathy. - Prof. Claus Lamm

That is, many definitions of empathy explicitly identify SOD as a fundamental and irreplaceable component, essential for both its conceptualization and practical application. Furthermore, Prof. Lamm stresses that beyond its role in empathy — where it prevents the conflation of one’s own emotions with those of others — SOD also serves as a core mechanism across various domains of mental state attribution. He highlights that SOD is "needed" and "meaningful" for a range of critical abilities like recognizing others' perspectives, predicting their behavior, and understanding their beliefs, all of which are vital for functional social cognition. 

For many researchers focused on self-other distinction, this paper offers a moment of clarity—yet, there are still murky waters to navigate and inconsistencies to address. Assoc. Prof. Dr. Giorgia Silani, Deputy Head of the Department of Clinical and Health Psychology and Head of the CSN-Unit at the University of Vienna, is among the 45 experts who contributed to this paper. While she affirms that SOD is "agreed upon and well defined,” she stresses a critical challenge that remains: the lack of operationalizational homogeneity across the various domains in which SOD is assessed. Specifically, a variety of tasks that differ significantly across multiple dimensions are used to assess SOD in the motor, cognitive, and affective domains. Prof. Silani argues that although reaching a consensus on the definition of SOD represents a significant leap forward in the field, the inconsistencies in SOD’s operationalization hinder the ability to draw precise inferences about the nature of the construct. 

There is a pressing need for research aimed at homogenizing these different operationalizations. - Prof. Silani

Dr. Ekaterina Pronizius, a postdoctoral researcher at UCLouvain, Belgium, and a Senior Research Fellow at the University of Vienna, is tackling the very issue that Prof. Silani highlighted, by focusing on refining the operationalization of SOD. While she also agrees with the definition of self-other distinction put forth by Quesque et al. (2024), she emphasizes that it lacks the precision necessary for the practical application of the construct. Dr. Pronizius explains that SOD is multifaceted and often divided into levels depending on the content of the mental representation being investigated. Importantly, there is considerable variability in how these levels are categorized: some researchers refer to SOD at the perceptual, motor, and cognitive level (e.g., Quesque & Brass, 2019), others distinguish between motor, cognitive, and affective SOD (e.g., Pronizius et al., 2024), and still others combine perceptual and motor SOD into a single category (e.g., Tomova et al., 2014). Moreover, some conceptualizations suggest that SOD may either be an overarching concept that subsumes both lower and higher hierarchical levels, or that multiple, partially independent "SODs" may exist. Dr. Pronizius emphasizes that advancing research on self-other distinction requires a more nuanced understanding of the concept. Accordingly, she explains that the clarity required can only be achieved by remedying this definitional imprecision:

Reaching a consensus on the various facets, levels, and the structure of SOD, along with developing robust and standardized measurement tools, is essential for effectively studying and applying this concept in both research and clinical contexts". - Dr. Pronizius 

Her conviction that a clearer conceptualization of SOD is urgently needed has been further reinforced by her large-scale, multi-lab project investigating SOD in borderline personality disorder (BPD). The idea that individuals with BPD experience impairments in social interactions dates back to Adolph Stern, the clinician who first coined the term "borderline" in 1938 (Stern, 1938). However, research on how impairments in social cognition in general, and SOD in particular, contribute to the symptomatology and maladaptive behaviors characteristic of BPD has only gained significant traction in recent years (De Meulemeester et al., 2021).

Dr. Pronizius presented preliminary findings from her project at the 2024 Social Cognition Workshop, an event she also co-organized. During the workshop, SOD emerged organically as a central theme, with discussions highlighting its potential for advancing our understanding of human cognition and social interactions. Attendees, most of them experts in the field, reached an emerging consensus that a robust theoretical framework, paired with valid measurement instruments, is essential for deepening insights into SOD impairments across various disorders. This approach, they agreed, would enhance our understanding of various psychopathologies (e.g., see Eddy, 2022), thereby reducing stigma and paving the way for more targeted therapeutic interventions.

Defining Key Concepts for Mental State Attribution represents a significant leap forward in a field long mired in ambiguity. In closing, we’d like to echo the paper’s core message: if the aim of the scientific community is the advancement of knowledge and to ensure the applicability of research findings, it is imperative that experts in this field transcend ideological divides and work collaboratively toward a unified conceptual framework. Further work is needed to refine the terminology surrounding mental state attribution. To this end, researchers are encouraged to align their efforts with the standards set by this landmark collaboration, thereby ensuring the avoidance of faux conceptual fragmentations, and fostering a unified commitment to scientific progress.

­1: Among the 45 researchers who accepted to take part on this project, 43 ultimately accepted to be listed as co-authors.

References

• De Meulemeester, C., Lowyck, B., & Luyten, P. (2021). The role of impairments in self–other distinction in borderline personality disorder: A narrative review of recent evidence. Neuroscience & Biobehavioral Reviews, 127, 242–254. https://doi.org/10.1016/j.neubiorev.2021.04.022
• Eddy, C. M. (2022). The Transdiagnostic relevance of self-other distinction to psychiatry spans emotional, cognitive and motor domains. Frontiers in Psychiatry, 13, 797952.  https://doi.org/10.3389/fpsyt.2022.797952 
• Pronizius, E., Bukowski, H., & Lamm, C. (2024) Comparing Self-Other Distinction Across Motor, Cognitive, and Affective Domains. Royal Society Open Science, 11, 240662. https://doi.org/10.1098/rsos.240662
• Quesque, F., Apperly, I., Baillargeon, R., Baron-Cohen, S., Becchio, C., Bekkering, H., ... & Brass, M. (2024). Defining key concepts for mental state attribution. Communications Psychology, 2(1), 29. https://doi.org/10.1038/s44271-024-00077-6 
• Quesque, F., & Brass, M. (2019). The role of the temporoparietal junction in self-other distinction. Brain Topography, 32(6), 943–955. https://link.springer.com/article/10.1007/s10548-019-00737-5 
• Stern, A. (1938). Psychoanalytic Investigation of and Therapy in the Border Line Group of Neuroses. The Psychoanalytic Quarterly, 7(4), 467–489. https://doi.org/10.1080/21674086.1938.11925367 
• Tomova, L., von Dawans, B., Heinrichs, M., Silani, G., & Lamm, C. (2014). Is stress affecting our ability to tune into others? Evidence for gender differences in the effects of stress on self-other distinction. Psychoneuroendocrinology, 43, 95–104. https://doi.org/10.1016/j.psyneuen.2014.02.006  

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 Further Links

• Annual Social Cognition Workshop "From Self-Knowledge to Knowing Others": https://www.self-knowing-others.org/  
• Prof. Lamm / SCAN-Unit: https://scan-psy.univie.ac.at/
• Prof. Silani / CSN Unit: https://klinische-gesundheit-psy.univie.ac.at/forschung/arbeitsbereiche-und-arbeitsgruppen/clinical-social-neuroscience-unit/  
• Dr. Ekaterina Pronizius’s personal webpage: www.pronizius.com
• Current Self-Other Distinction Projects: https://self-other.univie.ac.at/projects/