Towards Socially Sustainable Campuses: The Synergy of Spatial Affordances and User Agency in Hot–Humid Informal Learning Spaces

As universities strive for socially sustainable environments, Informal Learning Spaces (ILS) serve as vital social infrastructure. However, previous studies often isolate physical environmental stimuli from internal psychological decision-making and treat harsh climates as absolute barriers. To address this gap, this study integrates Environment–Behavior Studies (EBS) and the Theory of Planned Behavior (TPB) to construct a comprehensive behavioral model for ILS in hot–humid climates. Using Structural Equation Modeling on 377 samples from Guangzhou, China, the study quantifies the interaction between physical spatial affordances and internal psychological mechanisms. The results reveal a critical shift in behavioral drivers: when psychological agency is introduced, the driving force of high-quality Space Design (path coefficient = 0.269) surpasses the restrictive impact of the severe Climate Environment (coefficient = 0.218). This demonstrates that architectural affordances can actively buffer physiological discomfort. Internally, Perceived Behavioral Control (PBC)—acting as an empirical proxy for user agency—emerges as the sole psychological dimension directly driving actual spatial usage (coefficient = 0.131), whereas personal attitudes and peer pressure show no significant direct behavioral impact. Furthermore, the direct behavioral influence of operations management becomes non-significant when mediated by psychological expectations. Ultimately, this study reframes ILS optimization, demonstrating that socially sustainable campus revitalization in hot–humid regions must prioritize empowering user autonomy and enhancing robust morphological design over administrative upgrades or mere passive climate endurance.