Decoding Restorativeness: exploring the visual and perceptual foundations of environmental restorativeness through a psychophysical approach

This doctoral dissertation combines the existing knowledge from perceptual psychology and environmental psychology to explore the mechanisms underlying the construct of restorativeness (REST; i.e., the capacity of physical spaces to promote resource recovery for individuals), with a particular focus on identifying the basic visual components of a space that elicit restorative perceptions. Specifically, the research sought to clarify which elementary features of visual stimuli (BVFs) contribute to the global perceptual properties (BGPs) of natural scenes and how these, in turn, foster the sense of restorativeness. By integrating a psychophysical approach with Gestalt principles of perceptual organization, this dissertation aimed to bridge the gap between theoretical accounts of restoration and empirical evidence on visual processing. Restorativeness is a central construct in environmental psychology, referring to the capacity of certain environments - particularly those rich in natural elements - to promote the recovery of depleted emotional and cognitive resources (Hartig, 2004). A large body of research has shown that restorative environments enhance positive emotions and reduce stress (Mattila et al., 2020; Martinez-Soto et al., 2021; Sharam et al., 2022; Gentile et al., 2023), improve attention, concentration, and decision-making (Amicone et al., 2018; Aristizabal et al., 2021; Kimura et al., 2021), and even facilitate recovery in individuals with psychological disorders such as anxiety and depression (Meuwese et al., 2021; Stigsdotter & Grahn, 2003). These benefits have been observed through both subjective measures (e.g., self-report scales) and objective physiological indicators (e.g., heart rate, cortisol levels), highlighting the relevance of restorativeness for human health and well-being. The theoretical framework of this work combines well-established psychological models of restoration with perceptual theories. Attention Restoration Theory (ART; Kaplan & Kaplan, 1989) provided the conceptual basis for understanding how natural environments promote recovery of depleted attentional resources through “soft fascination.” Complementary approaches, such as the Scene-Centered Approach (SCA; Oliva & Torralba, 2006) and Feature Integration Theory (Treisman & Gelade, 1980), explained how early attentive bottom-up processes and global scene properties guide visual perception. Gestalt principles of perceptual organization further informed the assumption that restorativeness emerges from the aggregation of basic perceptual items into coherent global configurations. This integration allowed us to investigate restorativeness not only as a psychological construct, but also as the emergent outcome of visuo-perceptual mechanisms. Three studies were conducted to test these assumptions. The first contribution was a narrative review of psychophysical literature examining how bottom-up attention is captured by basic visual features of a stimulating visual configuration (i.e., an image), such as color, luminance, orientation, and closure. The review confirmed that these features and their gestalt-like relationships (e.g., proximity, symmetry, collinearity) activate pre-attentive grouping mechanisms, facilitating rapid scene segmentation and the emergence of perceptual “proto-objects.” This evidence supports the hypothesis that automatic attentional processes, central to ART, are grounded in low-level visual features. The second study empirically examined the role of Basic Global Properties (BGPs) of a scene - openness, expansion, depth, transience, and navigability - in predicting perceived restorativeness. Using both Likert scales and pairwise comparison methods on natural images, results showed that BGPs significantly predicted the four classical dimensions of REST (i.e., fascination, being away, coherence, scope). Moreover, interaction effects between structural (e.g., openness, expansion) and functional (e.g., transience, navigability) properties were observed, highlighting the combined contribution of multiple BGPs to restorative perception. The third study integrated ART, SCA, and Gestalt principles in a two-part experimental design. In Study 1, participants evaluated natural images on eight basic visual features (BVFs), which cluster analyses grouped into meaningful constructs corresponding to BGPs. In Study 2, image clusters derived from BVFs were tested as predictors of perceived restorativeness using mixed linear models. Results showed that clusters that differed in the presence of BGPs predicted different levels of perceived restorativeness. In particular, clusters characterized by higher levels of complexity, openness, and expansion elicited stronger perceptions of restorativeness and fascination compared to clusters dominated by texture features. Overall, the findings of this doctoral work indicate that restorativeness is not an inherent property of natural environments, but rather an emergent perceptual response shaped by the organization of basic visual features into global properties that attract involuntary attention. By identifying these perceptual “ingredients”, the project provides both theoretical advances in understanding restoration processes and practical implications for the design of human-made environments that foster psychological well-being.