Introduction
The concept of "tension" refers to a psychophysiological state arising from environmental pressures. It is shaped by the dynamic interaction of the built environment's characteristics, individual traits, and the situational context. Despite extensive evidence on the positive impact of factors such as green spaces, human scale, and interactive design on mental health, a structural research gap has hindered the practical application of this knowledge: existing studies primarily focus either on objectively measuring the environment or on subjective responses, without clearly explaining the operational mechanisms of how objective spatial features (such as visual density, lighting, and structure) translate into the subjective experience of tension. This gap prevents evidence-based design from effectively and purposefully reducing tension in public spaces. Therefore, this study aims to conduct a bibliometric analysis and knowledge visualization of the field, mapping existing research, identifying thematic clusters and scientific collaborations, and ultimately revealing key theoretical gaps to guide future research.
Theoretical framework
The research background related to public spaces and the sense of tension can be categorized into five interconnected key domains: studies on the overall impact of public spaces on tension, the relationship between environmental qualities and tension, the identification of influential environmental factors, methods for measuring tension, and citizens' sensory perceptions. Foundational studies, particularly those drawing on Attention Restoration Theory (Kaplan and Kaplan, 1989) and Stress Recovery Theory (Ulrich, 1984), have emphasized the vital and moderating role of green spaces and nature. This finding has been expanded by recent research (e.g., Prastowo and Syarif, 2024), which demonstrates that the quality (cleanliness, design, maintenance) of these spaces is more decisive than their mere quantitative presence. Concurrently, research has identified environmental factors that induce tension (such as poor design, pollution, visual and urban density) as well as mitigating factors (including noise reduction, a sense of shelter, diverse vistas, and effective architecture) (Matos et al., 2024; Khalighimoghaddam, 2024). However, reviewing this body of literature reveals two major structural gaps: first, the predominant focus of research has been on describing or quantitatively measuring phenomena, without systematically explaining the operational mechanisms (mediating processes) through which objective environmental characteristics translate into the subjective experience of tension; second, there is a notable absence of a comprehensive and integrated measurement framework that simultaneously captures and measures both the objective dimensions of the environment and individual sensory-psychological perceptions. These gaps hinder the formation of a comprehensive map of the knowledge structure and impede evidence-based design that could purposefully reduce tension in public spaces.
Methodology
This study is a bibliometric and scientometric investigation conducted with the aim of identifying research issues and gaps in the field of perceived tension in urban public spaces. To obtain a comprehensive overview of the scholarly output in this domain, data from 967 unique articles were collected from the Scopus and Web of Science databases (after removing duplicates). The search was performed using a combined strategy of keywords related to urban design, tension/stress, environmental psychology, and measurement indicators, with no time restrictions and covering all types of English-language articles. Scientometric analyses were conducted using VOSviewer software across four main levels: co-occurrence analysis to identify thematic clusters and trends, co-authorship analysis to map collaboration networks among authors, organizations, and countries, co-citation analysis to reveal intellectual paradigms and influential works, and citation analysis to identify highly cited articles and journals. Unlike descriptive scientometric studies, the findings in this research were interpreted through a problem-finding lens; that is, by focusing on structural gaps, weak connections between thematic clusters, emerging concepts, and collaboration patterns, fundamental issues and future research priorities were extracted.
Result and discussion
The structure of existing knowledge can be identified in five main clusters: theoretical foundations and socio-cultural dimensions (rich in theory but challenging in operationalization), mental health and risk factors (dominated by correlational approaches and limited in causal inference), thermal comfort and climate (specialized and precise, yet isolated from psychosocial knowledge), environmental perception and novel measurement technologies (forward-looking but in early stages and weakly linked to theory), and green infrastructure, spatial justice, and spatial methods (focusing on inequality and possessing spatial analysis potential, yet requiring more applied research). Three simultaneous developments have made addressing this issue essential: an explosive quantitative growth in research after 2015, a conceptual and methodological shift toward novel technologies and nature-based solutions, and the transformation of the need for tension-reducing public spaces into a social priority following the COVID-19 pandemic. Using a problem-finding approach, this study provides a framework for guiding future research toward filling these gaps and creating integrated, operational knowledge.
Conclusion
This research emphasizes that despite theoretical, empirical, and methodological advancements in the study of "perceived tension in public spaces," an integrated operational framework for measuring and managing this phenomenon is lacking. This deficiency stems from four main structural gaps:
• The theory-practice gap: The inability to translate scientific findings into practical design solutions.
• The objective-subjective measurement gap: The lack of connection between the physical characteristics of space and people's psychological experiences.
• The methodological gap: The insufficient and unsystematic use of modern measurement methods for evaluating designs.
• The contextual gap: The focus of research on developed countries and the neglect of different cultural and climatic conditions.
In simpler terms, although the factors influencing tension and their causes are partially understood, how to convert this knowledge into actionable guidelines for urban designers—unlocking the "black box" between space and experience—remains unclear.