The visceral experience of architecture: object affordance and our need to grasp our surroundings." By Nikos A. Salingaros



A quiet revolution is underway, in which architects are beginning to prioritize human neurological responses in what they build (Robinson & Pallasmaa, 2015; Sussman & Hollander, 2015). How does the human organism react and relate to a building, space, surface, or structural detail? A collaborative effort between architects and scientists, with cross-fertilization among disciplines, is revealing important new findings. This represents a paradigm shift after decades during which design focused almost exclusively on form, materials, and abstract geometries.

At the same time, we are discovering that traditional wisdom embedded in the built environment contains many of the design answers we now seek. Our ancestors who built towns and cities had an intuitive idea of which environments were more accommodating emotionally, and more healing (Alexander, 1979; Alexander et al., 1977). The tools they used to evaluate them were their own direct senses. Those older methods of choosing one design over another are now verified by our present-day laboratory techniques.

The sensory impact that our environment has on our nervous system and our body as a whole is the result of a complex mixture of distinct sources, all of which affect us viscerally. Our state of wellbeing is due in part to the effect that environmental information triggers in our body, coming from how our neurological system is designed for organismic survival during our evolution. Instinctive responses to form, pattern, and surface play a fundamental role in how we experience architecture.

Following the lead of Christopher Alexander (2001-2005), I have been investigating the organization of complexity (Mehaffy & Salingaros, 2015; Salingaros, 2006; 2011; 2014; 2015a). The central assumption is that our neurophysiological mechanism is developed for precisely this purpose — to analyze information automatically — hence theoretical results will help to explain how our body reacts to different environments.

Our neurophysiology picks up specific useful pieces of complex information from our surroundings. It does this subconsciously. Other, separate layers of our cognitive apparatus synthesize all this information to compute an integrated result. Our body then acts and reacts according to this internal cue. Building form adapts to our neurophysiology whenever all the individual internal elements, spaces, and surfaces — which should hopefully have followed criteria that guarantee an emotional connection — cooperate cognitively. Increasing the system’s interdependent relationships towards geometrical coherence consequently enhances its value in accommodating human life.


Brain architecture depends upon layers of complexity

Every complex system has different layers of complexity built onto a core foundation. This is evident in evolved organs such the brain, in which basic neural modules identified as “primary” or “primitive” brains are nested inside our own (Sussman & Hollander, 2015). Those older portions are essential because the organism depends upon them for basic life functions. The more advanced evolutionary layers that make us intelligent cannot work without the basic processing modules. DNA has a similarly nested structure, since our genetic code contains pieces from more primary or primitive life forms. A recent surprise (and blow to our ego) was to discover that those parts of DNA that make us characteristically human — hence infinitely more advanced — are relatively few.

By analogy, we can identify primary elements of architecture that are responsible for exerting the strongest influence of form and space on users. What we normally perceive as “architecture” is the surface of nested layers of a complex cognitive/response system. Less obvious but still primary (or primal) aspects of a building or a space influence our physiological and psychological responses: the success of a building or an urban space depends much more on these primal elements than on an intellectual analysis of its visible structure.

Hidden elements of complexity trigger neural signals when interpreting how a building or urban space works. Geometrical configurations have a significant neurological (yet largely subconscious) effect on our body. Those may be catalogued. The key mechanism within our neurological makeup known as “biophilia” defines primary sensorial needs from the living environment (Kellert et al., 2008; Salingaros, 2015b). This mechanism triggers our unselfconscious connection to the healing geometry of our surroundings. Innate neurophysiological mechanisms inherited from our evolutionary past instinctively attach us to our environment (Robinson & Pallasmaa, 2015; Sussman & Hollander, 2015).

Our body is a highly sophisticated complexity-processing device, which is constantly feeding on environmental information — but only if that belongs to a very special category that we evolved to handle. If environmental complexity overwhelms us, this creates anxiety because we cannot process its embedded information. It leads to a fight-or-flight response. Investigating how complexity can be organized geometrically gives us a tool with which to understand why our neurophysiology is set up to respond the way it does.

Together, the processes that affect us in a deep way encompass separate spatial perception and survival mechanisms. This broad topic helps to found a new approach to architecture and design that pays close attention to evolved human biology. Mechanisms that stimulate a positive neurophysiological response work only when organized complexity is present in the built environment. When it is not, the instinctive response in humans is often negative, triggering “phobias” instead of “philias”.


Our need to grasp nearby surfaces

Research in experimental psychology reveals the visceral nature of the human body’s reaction to graspable objects in its immediate vicinity (Jeannerod et al., 1995; Portugali, 1996). Visual images prompt the brain to affect our muscles directly. Neurological and hormonal signals prepare us mentally to grasp objects in our immediate environment that we perceive to fit our hand. Our brain identifies surroundings that offer such small objects as being accessible and touchable, a phenomenon called “object affordance”. Our visual and spatial attention is drawn to any graspable shape that is clearly defined as between two and eight centimeters (about 1 to 3 inches). This effect is prompted by both the physical entity itself and its image in our eye and brain.

Our feeling of reassurance at being in a room depends in part on whether it offers real or apparently graspable “handles”. These handles need not actually be grasped to provide the visceral benefit of their presence; they need only be nearby and appear readily available for grasping. I suggest that, in the context of design, the intensity of this physiological and psychological bond of object affordance is affected, positively or negatively, by several factors.


Table 1. Five characteristics of object affordance:

(i) A graspable item of a size to fit the average human hand helps us to perceive an environment as accommodating. Common examples include handles, edges, trim, frames, moldings, as well as surfaces with ornamental designs that seem to reach out to us in the hope that we will hold them, use them, caress them, acknowledge their existence; even if they are merely two dimensional.

(ii) The shape of physically graspable structural elements in a room should invite comfortable hand contact, even if it never actually occurs. A shape is more likely to satisfy our interest if it offers a smooth, rounded edge that will feel good to the touch.

(iii) “Object affordance” is strongest for elements on easily reachable surfaces, and weakest for graspable elements that are outside our physical reach. It diminishes slightly with distance. We connect best with accessible, touchable surfaces showing graspable shapes.

 (iv) By contrast, sharp, spiky, angular, rough, or otherwise visually unsettling objects, even if they are of the correct size, signal possible pain or injury when grasped, and repel instead of connecting positively. This sounds so obvious, but think of how frequently it is violated by designers of rooms or objects that one finds in rooms!

(v) Otherwise graspable objects in or elements of a room made of transparent, random, or amorphous materials do not invite grasping. They are invisible to the mechanism of “object affordance” and thus the allure never occurs.


 “Object affordance” acts subconsciously on people. Our motor neurons automatically react to perceivable articulations and designs in our immediate surroundings (Garrido-Vasquez & Schubo, 2014; McBride et al., 2012). Even if we don’t notice those reactions on a conscious level, the physiological state of our bodies — muscle tension and other neural activity triggered by “object affordance” — will nevertheless influence any action we take, including our reaction to just being there. A positive visceral reaction enhances a person’s well-being and performance, whereas a negative affordance set off by alienating structural details will influence all other actions negatively through superimposed anxiety and fatigue.

In his book The Thinking Hand (2009), Juhani Pallasmaa discusses this topic, though from a philosophical point of view rather than that of experimental psychology. Coming from a respected architect and educator, his message could have influenced contemporary design in a positive, humanistic direction. Unfortunately it didn’t, and we see examples from the work of modernist architects who eliminate built elements that might have invited “the thinking hand” to reach out for them.

Minimalist environments are intentionally bereft of graspable subdivisions and designs. Even structurally necessary frames and supports in such designed spaces are generally made either too small or too large to grasp, an intentionality of the design aesthetic. Minimalism is an approach to design that frustrates the object affordance mechanism, diminishing any visceral connection with our surroundings.


Scale dependence on small things

Among the elements of a room, including its windows, doors, furniture, ornamental detail, and things like door knobs and window latches, the relationships of scale reveal a complicated dependency: “The interdependence of scales is only one way: a higher scale requires all lower scales in order to function, but not vice versa.” (Salingaros, 2006: page 75). This means that the role in composition and utility of larger architectural elements is influenced by all of the smallest pieces; yet the smallest pieces either fit or fail to fit independently of the largest elements. Conceptually, this relationship is simple: smaller things literally uphold larger things. Components that correspond to bodily dimensions — our height, the length of our arms, the breadth of our hands, fingers, eyes, lips, nostrils, etc., between 1 millimeter and 2 meters (1/16 inch to 6 feet) — play a major supportive role in how we use buildings and urban spaces. The organization of ordered structure on these human scales shapes our experience of the entire building, beyond its details or ornament.

In design, no single scale should be valued above others, nor can it be sacrificed without understanding whether it serves a connective systemic (as opposed to artistic) function. Concentrating solely on the large-scale form of a building or urban complex, as is often done nowadays, can only lead to negative adaptation. In evaluating a design, small and intermediate scales may not be justifiable by aesthetic or even structural considerations, yet those scales are essential in adding systemic support to the whole.

Neurophysiological interaction with our surroundings demands the full spectrum of human scales in architecture. The smallest structural scales from 1 mm up to 2 cm (1/16 to 1 inch) are very often present when we decide to (and can afford to) use natural materials. Sometimes, the next higher scales from 2 cm to 8 cm (1 to 3 inches) are also included in natural grain and patterns, but we cannot assume that those scales will automatically arise in the same way every time. Natural materials do not normally show graspable dimensions, therefore, such scales need to be built and defined on purpose. The principal justification for this comes from object affordance (which contradicts the minimalist design aesthetic).

User wellbeing is linked to all the tectonic elements smaller in size than the human body cooperating to define an enveloping space. Our brain perceives the small and intermediate size structural elements together as either being coherent or not. Frames, trim, moldings, baseboards — all traditionally ornamental tectonic elements in a building that were eliminated in pursuing a minimalistic modernism — are now encouraged to come back. Not as decoration, nor for aesthetic or stylistic reasons, but because they are needed to anchor the large-scale spatial form within our cognitive system.

Most of these smaller components are essential structural reinforcements. Eliminating them throws a considerable burden on precision required when using large tectonic elements exclusively. Furthermore, erasing the smaller architectural scales removes the possibility of useful adjustments on those scales (Alexander et al., 1977). That drives up the cost, and forces us to rely upon large standard-size modules, which severely limits design freedom and adaptability. A building’s construction budget is very often squandered on an abstract aesthetic goal of “machine precision”, carefully controlling lines and edges to a very small tolerance, which does nothing for the users’ health and wellbeing. Ordinary people are not neurologically affected by machine precision (though many architects are, because of their training).

Contrary to popular thinking, removing information does not make a structure more useful by making it more generic. Information and substructure can be removed only if they are responsible for dissonance. Stripping down a space actually reduces its utility for any use requiring human participation, leaving us with an industrial shed. We see this poverty in environments that have been oversimplified through misguided top-down interventions.

A room of some standard size, with fixed ceiling height, window sizes and placements will not “fit” most situations emotionally, because of the entirely distinct needs, users, conditions, connections, etc. Neither can an architect re-use the identical minimal module in designing spaces for different uses, different climates, different societies, and different placement within a building in relation to all the other rooms, paths, and spaces. There are millions of sensory and cognitive cues to be satisfied, which will define a psychologically healthy environment. This reasoning rules out a generic “International Style” of design, triggering opposition from those who have bought into its supporting ideology. The cost-saving agenda of industrial standardization and homogenization conflicts with the science of human nature.


Moldings, window grilles, and nonlinear effects from concavity

Rooms with piecewise concave walls are perceived as accommodating, and work together with object affordance to adapt to our neurophysiology. Let’s begin with the small scale. Traditional moldings combine concave and convex portions: a concave part for psychological containment — the “enveloping effect” — and a convex part that invites “grasping”. This coupling of opposites makes traditional moldings necessary after all, and not merely as aesthetic decoration. The psychological function of moldings is to “reassure” us while we experience built space, by connecting us to its overall piecewise concave boundary.

The effect is moreover nonlinear. This means that a small portion of boundary will have a significant emotional effect beyond its relative size. While experiencing space, relatively small causes have large effects, influencing the whole beyond what one would expect from their size. Our neurophysiology developed to pick out tiny but important cues that are crucial for our survival, and this mechanism now interprets the built environment. It is a mistake to eliminate smaller architectural pieces, acting on the false assumption that because they are physically small their influence on the whole is also proportionately minimal. Quite the opposite is true.

In traditional architectures, a concave crown molding is often used to round out the join where the wall meets the ceiling. This transition region can range in width from only a few inches, to occupying a significant portion of the ceiling itself; and can even extend to create an entirely vaulted ceiling for a room. Providing this small-scale strip of concave boundary all around the ceiling’s perimeter enhances the overall enveloping effect: in this case a tiny percentage improves the subconscious feeling of reassurance of being enveloped in that space. It can also change the room acoustics dramatically.

Another instance where “object affordance” combines with concavity occurs in traditional bay windows (Alexander et al., 1977). Here, a reassuring environment partially envelops one or more persons while connecting visually to the outside. Using the vocabulary of biophilia, successful bay windows combine “refuge” with “prospect” (Kellert et al., 2008; Salingaros, 2015b). There should be no confusion between glass curtain walls (which offer no information, hence no protective psychological boundary), and the solid structural frame/grid that defines the spatial and visual boundary of bay windows (which give the cognitive experience of pleasurable enclosure).

It is not the transparent glass but the grilles or muntins between panes and the mullions between entire window units, which provide this crucial psychological attachment. Small windowpanes traditionally come with a “graspable” frame of exactly the right thickness to satisfy “object affordance”, and the muntins would fit the hand nicely (Alexander et al., 1977). A bay window made from plate glass with either minimal or no internal frame, nor any subdivisions, creates anxiety rather than a “reassuring” spatial experience. Neurophysiology rules against the undifferentiated glass curtain wall.


Including all of our other senses

The ambient information field is akin to a force field that ties us to our surroundings (even though there is no physical exchange taking place). Articulations and details that define a welcoming environment are either missing, or are juxtaposed incoherently in many of today’s buildings. An abstract design that looked fine, but which failed to evaluate — and adjust for — all predictable human reactions could turn out to be a threatening or oppressive environment when built. Users will avoid those architectural spaces, or force themselves to use them while fighting increased stress levels. Apparently benign design decisions can trigger negative physiological responses in the user. This comes from not thinking about the consequences, or worse, having being falsely taught that there are no consequences.

A space designed for a predetermined function and use could be more suitable for a totally different behavior; or it could be dysfunctional, because our body is reacting viscerally to that space’s geometry, surfaces, details, and complexity (or lack of it) in an unexpected way. Countless complex interactions combine to generate a visceral signal, which determines a comparatively simple set of behaviors for the user. Our body tells us what to do. This result is more basic than either psychology or medicine, and underlies all of architecture and design.

Environmental stimuli are constantly being interpreted by our sensory system, generating physiological responses felt within our entire body. This effect depends upon superimposed contributions from all of our senses. Those include — but are not limited to — sight, hearing, smell, balance, touch, invisible electromagnetic radiation (for example, infrared heat exchanged from hot or cold surfaces, and frequencies that our body experiences directly), and a kinesthetic awareness of our surrounding space. Contributions from distinct mechanisms act on different scales and at different ranges. The complex character of the interactions changes with the physical distance between the human body and a structure or surface.

In The Eyes of the Skin (1996), Juhani Pallasmaa discusses the non-visual components of our sensory experience interpreting our environment, which contribute to how structures affect our body. While this book is an assigned reading in architecture schools, it does not seem to have the hoped-for impact either in studio, or in practice. Architects love to refer to it, yet invariably, their designs fail to embody the qualities it describes! Instead of training architects to be sensitive to non-visual environmental interactions that either trigger or reduce anxiety, conventional design pedagogy focuses instead on formal approaches and visual novelty.



Human beings respond to spaces, surfaces, detail, and ornament viscerally, which determines how a built structure will actually be used independently of whatever the architect intended. Yet as long as the design has followed basic adaptive principles, sometimes surprising emergent phenomena could enhance and not detract from the users’ experience of the built structure. Design components joined together coherently communicate a strong message, which is read by our senses. In the best of cases, the building, or portions of it, evoke a “sense of belonging” that accommodates users. The built environment thus acquires welcoming properties. In exceptional cases, moreover, this perception could translate into a “sense of wonder”, such as occurs in the great religious buildings of the past.

Finally, the interacting system of building-plus-user is not only a system in space, but also one in time. Geometrical components interact with users on distinct spatial scales, but we should also design for the different and changing movements of people, users of different characteristic time periods, for the changing time of day, etc. All those temporal scales need to interact in a coherent manner, coordinated rather than restricted and frustrated by some “designed” form. Whenever emergent design is successful, the complex temporal system will interact seamlessly with the complex spatial system (while treated independently for practical reasons during the design process) as one space-time system.



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Nikos A. Salingaros (2015b) “Biophilia and Healing Environments”, a 10-part series in Metropolis, August–September. Published together as a booklet by Terrapin Bright Green, LLC, New York. Available from: <>

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