Enhancing Connection: The Role of Complexity and Mystery in Environmental Involvement

Every day, you move through dozens of environments – your home, a park, a busy street, a quiet library. Some of these spaces feel dull and forgettable. Others pull you in, make you linger, and leave a lasting impression. What makes the difference? Environmental psychologists have found that two key properties – complexity and mystery – play a major role in how deeply we connect with a space. These elements shape not just whether we like an environment, but how involved we become with it.

The Kaplan preference matrix: a framework for environmental involvement 🔗

The foundation for understanding environmental involvement comes from the work of environmental psychologists Rachel and Stephen Kaplan. In their influential 1989 book The Experience of Nature: A Psychological Perspective, the Kaplans proposed that humans have two fundamental needs when interacting with environments: the need to understand the space and the desire to explore it. They further recognized that these needs can operate at two levels – what is immediately visible and what can be inferred by moving deeper into the space.

By crossing these two needs with these two levels, the Kaplans created a preference matrix consisting of four informational variables: coherence (immediate understanding), legibility (inferred understanding), complexity (immediate exploration), and mystery (inferred exploration). Each variable contributes to how much a person prefers and engages with a given environment. Among these, complexity and mystery are the two that drive involvement – they pull people into active engagement with their surroundings rather than passive observation.

What is environmental complexity? 🔗

Complexity refers to how much is going on in an environment – how many different elements, textures, colors, and patterns are present in a scene. A complex environment is visually rich and varied. It has a lot to look at and process, which stimulates the desire to explore.

A study published in Sustainability found that all three measured attributes of complexity – variety of elements, number of colors, and organization of elements – significantly influenced people’s preferences for urban parks. The more diverse and visually varied a park was, the more likely people were to choose it over simpler alternatives.

Why complexity captures attention 🔗

Complex environments engage us because they present a wealth of information that our brains are motivated to process. When you walk into a botanical garden with dozens of plant species, winding paths, water features, and varying terrain, your visual system is immediately activated. There is simply more to look at, more to distinguish, and more to take in.

This idea has roots in earlier work by psychologist Daniel Berlyne, who studied the relationship between stimulus properties and aesthetic preference. Berlyne proposed that properties like complexity, novelty, and surprise influence a person’s arousal level, which in turn drives their preference for a stimulus. His theory suggested that moderate levels of arousal – and by extension, moderate complexity – tend to produce the most positive responses. Too little complexity is boring; too much becomes overwhelming.

The Kaplans built on this idea but shifted the focus from raw arousal to information processing. For them, complexity is not just about stimulation – it is about the richness of information available for immediate exploration. A complex scene says: “There’s a lot here – come explore.”

Complexity in natural and built environments 🔗

Complexity operates differently across environment types. In natural settings, complexity often comes from biodiversity – mixed vegetation, layered canopies, varied topography, and the interplay of light and shadow. A meadow bordered by forest with a stream running through it is more complex than a flat, mowed lawn.

In built environments, complexity arises from architectural detail, diversity of materials, signage, human activity, and the arrangement of buildings and streets. A lively neighborhood market is more complex than a blank concrete wall. Research on urban environments has consistently found that the presence of natural elements – such as trees, gardens, and water features – adds a layer of complexity that increases environmental preference.

However, there is an important nuance. Complexity alone does not guarantee preference. If a space is complex but chaotic – with no discernible organization – it may feel confusing rather than inviting. This is where complexity benefits from working alongside coherence, another variable in the Kaplan matrix. Coherence provides a sense of order that makes it possible to engage with a complex scene without becoming overwhelmed.

What is mystery in an environment? 🔗

Mystery is about the promise of new information. It refers to any features in an environment that suggest there is more to discover if you move deeper into it. A curving trail that disappears behind a hill, a partially hidden garden glimpsed through an archway, or a forest path that bends out of sight – all of these contain mystery. They draw you forward with the implicit promise that something interesting awaits.

Unlike complexity, which is about what you can immediately perceive, mystery operates at the inferred level. It is not about what you see right now but about what you could see if you took a few more steps. This distinction is critical because mystery engages a different psychological process: curiosity.

Mystery as a predictor of preference 🔗

Across decades of research, mystery has emerged as one of the most consistent predictors of environmental preference. A meta-analysis by Arthur Stamps reviewing 28 studies and over 6,000 participants found that among the four informational variables, mystery showed the most reliable positive association with landscape preference. People are consistently drawn to environments that hint at hidden information.

Research on forest settings further supports this. Studies by Thomas Herzog and colleagues at Grand Valley State University examined the relationship between mystery and preference in within-forest settings. They found that mystery was positively linked to preference, particularly in settings where visual access was sufficient for people to feel safe exploring further.

How mystery works psychologically 🔗

Mystery engages what psychologists call exploratory behavior. When a scene suggests that hidden information is available, it activates a motivational pull to move forward and find out more. This is not a conscious, analytical decision – it is an instinctive response rooted in our evolutionary history. Environments that promise new information held adaptive value for early humans, who needed to constantly assess their surroundings for food, water, shelter, and threats.

At a cognitive level, mystery triggers a form of attention that psychologists describe as soft fascination. This concept, central to the Kaplans’ Attention Restoration Theory (ART), refers to stimuli that capture your attention effortlessly – without demanding the kind of focused, effortful concentration that eventually leads to mental fatigue. A winding river, a path that curves out of sight, or a sunlit clearing visible through dense trees are all sources of soft fascination.

This is different from what the Kaplans called hard fascination – stimuli that demand your attention forcefully, like a loud siren or a flashing screen. Hard fascination grabs you, but it does not restore you. Soft fascination, fueled partly by mystery, gently engages your involuntary attention and gives your depleted directed attention a chance to recover.

Mystery, fascination, and attention restoration 🔗

The connection between mystery and restorative attention has been investigated directly. A study by Szolosi, Watson, and Ruddell published in Frontiers in Psychology examined how mystery in nature scenes affects recognition memory, a proxy for attentional engagement. Participants viewed nature images rated as either high or low in mystery. The results showed that with additional viewing time, images high in mystery produced greater improvements in recognition performance than low-mystery images. Importantly, mediation analysis revealed that mystery’s effect on recognition performance worked through perceptions of fascination – confirming the Kaplans’ theoretical prediction.

A follow-up eye-tracking study by Marois and colleagues measured how people’s eyes behaved when viewing high-mystery versus low-mystery nature images. Participants showed larger pupil dilations, more fixations, and fewer blinks when viewing high-mystery scenes – all indicators of greater attentional engagement. These findings suggest that mystery does not just passively soothe attention but actively engages it in a way that may support cognitive recovery.

This presents an interesting nuance to ART. The original theory suggested that restorative environments let directed attention rest. But these findings indicate that mystery-rich environments may restore attention not by turning it off but by redirecting it – shifting the brain from effortful, top-down processing to a more automatic, bottom-up mode of engagement that feels less taxing.

How complexity and mystery work together 🔗

Complexity and mystery are not isolated forces. In real environments, they often co-occur and reinforce each other. A dense forest with varied vegetation (complexity) and paths that wind out of sight (mystery) combines both elements. A vibrant street market filled with diverse goods (complexity) and narrow alleyways branching off into unknown neighborhoods (mystery) does the same.

When both elements are present, involvement deepens. Complexity ensures there is enough variety to sustain interest, while mystery creates a forward pull – a reason to keep going and see what comes next. Together, they create what could be described as a feedback loop of engagement: complexity provides the sensory richness, and mystery gives it direction and purpose.

Implications for design and planning 🔗

Understanding the roles of complexity and mystery has practical value for architects, urban planners, and landscape designers. Spaces that feel sterile or monotonous typically lack both elements. A long, straight corridor with blank walls offers neither complexity nor mystery. A well-designed park, on the other hand, might use mixed plantings for complexity and curving sightlines for mystery.

Research on the impact of environment type on attention restoration supports the idea that designed environments can leverage these principles to promote wellbeing. Natural settings with high mystery have been associated with greater perceived restoration potential, suggesting that parks, trails, and gardens designed with these features could serve as more effective mental health resources for urban populations.

Some specific design strategies include using curved pathways instead of straight ones to create mystery, incorporating diverse planting schemes to increase complexity, using elevation changes and partial screens (such as hedges or walls) to partially obscure views, and varying materials, textures, and lighting to add visual richness.

The evolutionary perspective 🔗

The Kaplans’ framework is rooted in an evolutionary perspective. The idea is that human preferences for complex, mysterious environments are not arbitrary cultural products but reflect adaptive tendencies shaped over millennia. Environments that offered both rich information (complexity) and the possibility of discovering additional resources or threats (mystery) would have given early humans a survival advantage. Those who were drawn to explore such environments would have been more likely to find food, water, and safe shelter.

This evolutionary grounding helps explain why these preferences appear across cultures and age groups. While individual tastes certainly vary, the general pattern – that complexity and mystery increase environmental preference and involvement – has been replicated in studies spanning multiple countries and demographic groups.

The limits of complexity and mystery 🔗

Neither complexity nor mystery is beneficial in unlimited quantities. As noted earlier, excessive complexity without coherence produces confusion and discomfort. Similarly, mystery without a sense of safety can generate anxiety rather than curiosity. A dark, unfamiliar alley may contain mystery, but if it also feels threatening, the response will be avoidance rather than exploration.

Research by Herzog and colleagues has shown that perceived danger moderates the relationship between mystery and preference. In forest settings without pathways, mystery was only positively related to preference when participants also felt they had adequate visual access – the ability to see into the environment sufficiently to judge its safety. When visual access was low and the setting felt enclosed and threatening, mystery lost its positive effect.

This means that effective environmental design requires a balance. The goal is to offer enough complexity to be stimulating, enough mystery to invite exploration, enough coherence to be understandable, and enough legibility to feel safe. All four variables in the Kaplan matrix work in concert, and optimizing for involvement means attending to all of them.

Bringing it together: why involvement matters 🔗

Environmental involvement is more than an academic concept. It affects how long people spend in a space, how positively they remember it, and how much psychological benefit they derive from it. Environments that foster deep involvement through complexity and mystery tend to be preferred, sought out, and experienced as restorative.

In a world where attention is constantly fragmented by digital demands and urban noise, spaces that naturally engage our curiosity and exploration may be more valuable than ever. Understanding what makes these spaces work – the right mix of variety and the promise of discovery – gives us tools to create environments that support not just functionality, but genuine psychological connection.

What do you think? Have you noticed certain environments pulling you in more than others because of their visual richness or sense of hidden discoveries? How might an awareness of complexity and mystery change the way you experience or design the spaces around you?

References

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