In recent years, cultural and public institutions have increasingly moved beyond purely visual presentations to create immersive, multi-sensory experiences. This shift acknowledges that human perception is an integrated process, shaped by the interplay of all senses. Within this trend, there is a growing interest in designing environments that are not only engaging but also psychologically restorative. While the restorative benefits of natural environments are well-established, the translation of these benefits into curated indoor settings, such as art exhibitions, is an area of active exploration. However, a significant gap remains in understanding the specific design principles that maximize these restorative effects. A systematic review highlighted that the influence of sensory perception across different modalities on physiological stress is a critically underexplored area.1
This paper addresses this gap by focusing on the role of sensory congruence—the thematic and semantic alignment of stimuli across different sensory channels—in the context of landscape photography exhibitions. The central research problem is to determine whether adding congruent, nature-based soundscapes and scents to visual landscapes enhances restorative outcomes more effectively than adding incongruent stimuli or single sensory inputs. The objectives of this paper are: (1) to synthesize the literature on the restorative effects of visual, auditory, and olfactory stimuli; (2) to examine the theoretical and empirical evidence for sensory congruence as a critical factor in multi-sensory perception; (3) to propose a robust methodology for measuring the physiological, cognitive, and affective impacts of such installations; and (4) to provide evidence-based insights for the design of effective restorative multi-sensory environments.
The theoretical foundation for this research is rooted in environmental psychology, particularly Attention Restoration Theory (ART), and the neuroscience of multi-sensory integration. ART posits that natural environments can combat mental fatigue by engaging involuntary attention, thereby allowing directed attention capabilities to recover.2 While early research relied on subjective questionnaires, the field has evolved to incorporate objective physiological indicators such as electroencephalography (EEG), heart rate variability (HRV), and salivary cortisol, which are considered more sensitive measures of stress and restoration.2
Research consistently demonstrates that auditory and olfactory stimuli are powerful agents of psychological restoration. Studies using facial electromyography (EMG) found that auditory and audiovisual environments were significantly superior to visual-only environments for relieving stress, with the auditory condition showing the largest decrease in muscle tension.3 In terms of long-term effects, auditory stimuli have been shown to produce the most significant stress reduction compared to visual stimuli.4 In a field study of a forest recreation area, auditory sensations had the highest positive impact on both perceived restorativeness and visitor satisfaction, surpassing visual, olfactory, and tactile sensations.5 However, the effect of sound is complex; a meta-analysis concluded that auditory stimulation can also reduce HRV indices, suggesting a decrease in vagal autonomic modulation that warrants careful consideration in environmental design.6
Olfaction holds a unique and potent connection to memory and emotion, a link explored in artistic and scientific projects like ‘Site and Smell,’ which investigates how ‘smell-scapes’ trigger spatial memory.7 The reactivation of sensory-rich emotional memories can be effectively triggered by olfactory cues.8 In clinical settings, olfactory stimulation has proven highly effective for stress reduction. One study found that an olfactory-only condition produced the most significant increase in RMSSD, an HRV marker of parasympathetic (rest-and-digest) activity, with an 81.6% rise compared to control.9
While individual senses are potent, their combination can produce synergistic effects. Immersive virtual reality studies show that multi-sensory (audiovisual-olfactory) stimulation provides greater psychological recovery than unisensory or bisensory modes.10 Similarly, a combined tactile-olfactory intervention was found to be the most effective multi-sensory approach for reducing anxiety and physiological stress in a healthcare setting.9 This synergy is not merely additive but reflects deep-seated neural processes; short-term multisensory training induces neuroplasticity in specific multisensory brain structures, such as the right Superior Temporal Gyrus, rather than in unisensory cortical areas.11
The critical factor mediating the effectiveness of multi-sensory experiences appears to be congruence. Cross-modal correspondences, or the ‘fit’ between stimuli, influence integration and perception. A study on perceptual learning found that memory traces for incongruent audiovisual pairs were significantly weaker and decayed faster than those for congruent pairs.12 This cognitive cost of incongruence is well-documented. Incongruent trials in an Implicit Association Test resulted in significantly slower response times and lower accuracy.13 Neurally, this incongruence does not change the decision threshold but slows the rate of evidence accumulation, meaning the brain works harder and less efficiently to process mismatched signals.13 This suggests that for a restorative environment to be effective, the sensory components must be thematically and semantically aligned to facilitate effortless processing and prevent cognitive dissonance.
To empirically test the effects of sensory congruence in a landscape photography exhibition, a multi-group experimental design is proposed. This design allows for the systematic isolation and comparison of different sensory inputs and their combinations.
A between-subjects design would compare the experiences of participants randomly assigned to one of five conditions:
The target population for this study would be the general public, recruited from the community to enhance the generalizability of the findings. While much psychological research relies on convenience samples like university students, using a broader demographic provides a more ecologically valid assessment of how such installations might function in real-world public spaces. Screening would be necessary to exclude individuals with specific sensory impairments (e.g., anosmia) or medical conditions that could confound physiological measurements.
A multi-modal measurement approach is essential to capture the comprehensive effects of the intervention across physiological, cognitive, and affective domains.
Based on the reviewed literature, a clear pattern of results can be hypothesized. The analysis would focus on comparing the changes in outcome measures from pre- to post-intervention across the five experimental groups.
It is expected that conditions involving auditory stimuli (Congruent, Incongruent, Audio-Only) will demonstrate greater stress reduction than the visual-only Control condition. This aligns with findings that auditory and audiovisual environments produce superior stress relief compared to visual-only settings3 and that auditory sensations are a primary driver of perceived restorativeness.5 The multi-sensory conditions, particularly the congruent one, are hypothesized to yield the most significant overall benefits.
The central hypothesis is that the Congruent Multi-Sensory Condition will produce the most substantial positive outcomes across all measures: the greatest reduction in physiological stress markers (cortisol, sympathetic HRV activity), the largest improvement in cognitive performance, and the highest ratings of positive affect and valence. This is because congruent stimuli facilitate efficient cross-modal integration and create stronger, more coherent perceptual experiences.12
Conversely, the Incongruent Multi-Sensory Condition is expected to be the least effective, potentially performing worse than the single-modality conditions or even the control. The cognitive load required to process conflicting sensory information13,15 is likely to counteract any potential restorative benefits of the individual stimuli. This cognitive dissonance may manifest as increased physiological arousal and negative affective ratings.
The analysis will also explore the nuances between different physiological markers. It is possible that subjective reports of stress may not perfectly align with biological markers like cortisol, as seen in studies of other interventions like yoga.16 Furthermore, markers like HRV may not distinguish between positive excitement (eustress) and negative stress (distress), whereas subjective affective ratings can.14 It is also predicted that the Scent-Only condition will show a particularly strong impact on parasympathetic HRV markers like RMSSD, consistent with prior research.9
The anticipated findings carry significant implications for both theory and practice. The results would provide strong empirical support for the principle that sensory congruence is not an aesthetic afterthought but a critical functional component in the design of restorative environments. The enhanced effect of the congruent condition can be interpreted through the lens of ART; by creating a seamless and believable multi-sensory world, the installation more effectively promotes a sense of ‘being away’ and ‘fascination,’ allowing directed attention to rest.
The cognitive cost associated with processing incongruent stimuli13 provides a compelling explanation for why poorly designed multi-sensory environments may fail or even induce stress. When the brain must actively work to resolve a conflict between what it sees, hears, and smells, it cannot enter a restorative state. This underscores that the mere addition of sensory stimuli is insufficient; their integration must be coherent.
Practically, this research offers evidence-based guidelines for artists, curators, museum designers, and architects. To maximize the well-being of visitors, exhibitions and public spaces should incorporate thematically aligned sensory layers. This approach has direct relevance for arts-and-science collaborations aiming to explore sensory perception, such as the ‘Site and Smell’ project focused on olfactory memory7 or the ‘Cemetery’ project using infrasonic recordings.17 Theoretically, this work would extend ART by demonstrating how specific sensory design choices modulate its core mechanisms. It also contributes to the field of multi-sensory integration by linking the principle of cross-modal correspondence to tangible psychophysiological outcomes.
Several limitations and counter-findings must be acknowledged. The relationship between sensory stimuli and physiological response is complex. For instance, while often restorative, auditory stimuli can, in some contexts, reduce HRV, indicating a potential stress response.6 There is also a well-documented potential for disconnect between subjective feelings of well-being and objective physiological markers. Studies have shown that participants may report reduced stress without corresponding changes in cortisol16 or that physiological stress markers may not differentiate between positive and negative arousal.14
Furthermore, the application of multi-sensory environments requires caution, particularly with vulnerable populations. Research has shown that such environments can pose cardiac risks for patients with specific disabilities or those on certain medications (e.g., anti-epileptics) that affect the heart’s QT interval.18 This highlights the ethical imperative to consider the target audience and potential contraindications when designing public installations. Finally, the findings from a general population sample may not be directly applicable to clinical populations or specific high-stress occupational groups without further research.
This paper argues that the intentional design of multi-sensory immersive installations, guided by the principle of sensory congruence, holds significant potential for promoting psychological restoration. By synthesizing literature from environmental psychology and neuroscience, we have outlined a clear theoretical rationale and a robust methodological approach for investigating the synergistic effects of thematically aligned soundscapes and scents in a landscape photography exhibition. The expected findings suggest that congruence is key to unlocking the restorative benefits of multi-sensory experiences, while incongruence can impose a cognitive load that undermines them.
Future research should expand on this framework by exploring a wider array of sensory combinations, including tactile and haptic inputs.9 The principles should also be tested in diverse applied settings, such as healthcare waiting areas, educational institutions, and workplace wellness rooms. Longitudinal studies are needed to understand the long-term effects of repeated exposure to such environments. Finally, incorporating advanced neuroimaging techniques like fNIRS and EEG could provide deeper insight into the real-time cortical dynamics underlying sensory integration and attention restoration during these immersive experiences.14,15
