Architectural Lessons From Environmental Psychology:
The Case of Biophilic Architecture
Yannick Joye
Free University of Brussels
A review of findings from the field of environmental psychology shows that humans are
aesthetically attracted to natural contents and to particular landscape configurations.
These features are also found to have positive effects on human functioning and can
reduce stress. However, opportunities for contact with these elements are reduced in
modern urban life. It is argued how this evolution can have subtle but nontrivial adverse
effects on psychological and physiological well-being. These can be countered by
integrating key features of natural contents and structural landscape features in the built
environment. Several practical proposals are discussed, ranging from literal imitations
of natural objects (such as plants) to the use of nature’s fractal geometry in an
architectural context.
Keywords: biophilia, environmental psychology, fractal architecture, biophilic archi-
tecture
Natural objects, shapes, and processes have
often acted as a source of inspiration throughout
the history of architecture. Perhaps the most
obvious example of this inspiration is ornament,
which often contains representations that are
closely similar to, or reminiscent of, the animal
and plant world. Besides such literal imitations,
some architects, notably Antonı´ Gaudı´, drew
lessons from the structural forces governing natural
structures, resulting in efficient and economically
built architecture (e.g., Sweeney &
Sert, 1960). Today, there seems to be a renewed
interest in the relation between nature and architecture,
especially in zoomorphic or biomorphic
architecture (e.g., Feuerstein, 2002). More
specifically, such architecture makes use of digital
design software, which allows one to easily
recreate the curvy shapes and geometry that are
characteristic of natural entities (Lynn, 1999).
This article affirms the importance of natural
form as a perennial source of inspiration for
architecture. In fact, the main conclusion of this
study is that nature-based forms and organizations
in architecture are valuable for human
emotional and cognitive functioning. However,
the exact way in which this conclusion is
reached differs in an important respect from the
narratives and arguments proposed in theories
of organic and biomorphic architecture, which
are often more philosophical (Lynn, 1998) or
even pseudophilosophical (e.g., Steiner, 1999)
in nature. In contrast, the argument for naturebased
forms in architecture in the current study
is mainly based on empirical findings from diverse
psychological subdisciplines. In particular,
the article starts with a concise review of
empirical findings from the field of environmental
psychology and aesthetics. This survey
reveals that humans have an emotional relation
with natural elements and shows that contact
with natural form is in a sense good for human
psychological and physiological functioning. It
is argued that, by architecturally mimicking natural
forms and structural organizations of natural
settings, these beneficial effects can be
tapped in a built context.
The Psychoevolutionary Framework
Different psychological subfields study the
human relation with nature. For example, evolutionary
psychologists argue for the existence
of cognitive modules that are specialized in
conceptual and perceptual knowledge about
Yannick Joye, Business Economics and Strategic Policy
(BEDR), Free University of Brussels, Belgium.
Correspondence concerning this article should be addressed
to Yannick Joye, Business Economics and Strategic
Policy, Pleinlaan 2, B-1050 Brussels, Belginm. E-mail:
yannick.joye@telenet.be or yannick.joye@vub.ac.be
Review of General Psychology Copyright 2007 by the American Psychological Association
2007, Vol. 11, No. 4, 305–328 1089-2680/07/$12.00 DOI: 10.1037/1089-2680.11.4.305
305
natural entities. Such cognitive devices are
claimed to have evolved to handle the survivalrelated
challenges and opportunities that were
present in the natural settings in which human
ancestors lived (e.g., finding food; Mithen,
1996; Pinker, 1994). Scott Atran (1995) argues
how cross-cultural similarities in human folkbiologies
support the existence of such a system.
In particular, Western and non-Western individuals
seem to classify nature in similar ways and
consistently ascribe essences to the taxonomic
types of folkbiologies. Atran’s view is consistent
with the literature on category-specific deficits,
in which people are reported to have deficient
perceptual and conceptual knowledge
about the category of living things. One of the
interpretations of the causes of such deficits is
that, under evolutionary pressures, specific neural
areas have become specialized in information
about living entities (e.g., Caramazza &
Shelton, 1998).
Perhaps the psychological field that has most
profoundly studied the human (affective) psychological
relation with natural entities is environmental
psychology. This research area draws
on numerous empirical studies and is, therefore,
less speculative than the just-mentioned modularity
thesis. One of the central issues of environmental
psychology is how different types of
settings can trigger different affective states in
individuals (e.g., liking or preference reactions).
Two important proposals have been advanced
with regard to the specific process underlying
these emotional states. In the preference matrix,
developed by Stephen and Rachel Kaplan, the
occurrence of such states is to a large extent the
result of cognitively assessing whether certain
informational features are present in a setting
(R. Kaplan & Kaplan, 1989). This contrasts
with a central tenet of Roger Ulrich’s (1983)
psychoevolutionary framework. In this model,
which will form the backbone of the current
study, affective responses toward environmental
settings are not mediated by cognition but
stem from a rapid, automatic, and unconscious
process by which environments are immediately
liked or disliked. These fast affective reactions
are claimed to be rooted in human evolutionary
history and are essentially adaptive:
They motivated the organism to quickly undertake
actions that contributed to its well-being
and survival. For example, if early humans
came across a setting containing an important
risk (e.g., turbulent water, a predator), this triggered
negatively toned affective reactions (e.g.,
dislike), ultimately leading to avoidance behavior.
On the other hand, if a setting offered good
opportunities for survival and reproduction, this
would have caused liking reactions, leading to
explorative behavior.
In agreement with Ulrich’s (1983) model,
empirical evidence shows that environments
(e.g., urban vs. natural) are processed according
to their affective valence. Moreover, this process
seems to occur very rapidly, which supports
the immediate and automatic character of
these affective responses (Hietanen & Korpela,
2004; Korpela Klemettila¨, & Hietanen, 2002).
According to the psychoevolutionary framework,
survival chances further increased if these
emotional reactions had an inherited component:
No precious time and energy had to be
spent learning what kinds of environments were
either beneficial or harmful (S. Kaplan, 1987,
1988; Ulrich, 1983). With regard to the neural
origin of these affective states, some researchers
attribute an important role to subcortical areas,
especially the amygdala. Because these structures
are also involved in modulating stressrelated
hormones, it provides an explanation of
why certain types of settings have a different influence
on autonomic stress responses (Parsons,
1991; see also Joye, 2007, for an in-depth discussion
of this issue).
Aesthetic Preference and Structural
Landscape Features
What is the character of the settings or elements
that can trigger such immediate affective
states? The literature states that, on the one
hand, these reactions can be provoked by some
typical structural landscape features. Although
coming from a different research field, geographer
Jay Appleton was one of the first to propose
a model addressing this issue (Appleton,
1975). According to Appleton’s prospect–
refuge theory, human beings’ preference for
landscapes correlates with two environmental
qualities: prospect and refuge. The notion of
prospect refers to settings or landscape elements
that facilitate obtaining information about the
environment. A typical example is a hill, which
aids to visually access and inspect the surrounding
area. On the other hand, refuge points to
settings that can provide shelter and protection.
306 JOYE
An evident example is a cave, which can protect
against predators and weather conditions.
Ulrich’s psychoevolutionary framework lists
some other visual cues that are associated with
immediate positive affective reactions: complexity,
gross structural properties (e.g., patterns),
depth properties, ground surface and
texture, absence of threats, and deflected vista
(Ulrich, 1983). The predictors in Rachel and
Stephen Kaplan’s preference matrix overlap to
a certain extent with the variables listed by
Ulrich. The Kaplans’ model (R. Kaplan &
Kaplan, 1989; S. Kaplan, 1987, 1988) describes
two types of postures toward the environment.
An individual can be actively involved in an
environment: One can, for example, explore the
setting. Alternatively, an individual can try to
understand the environment. The Kaplans argue
that these two attitudes are associated with four
structural landscape properties, each of which
correlates with positive aesthetic evaluations
and positively influences landscape selections.
The structural properties that facilitate involvement
in the environment are complexity and
mystery. Stephen Kaplan defines complexity as
a measure for “how much is ‘going on’ in a
particular scene, how much there is to look at”
(1988, p. 48). Mystery refers to settings whose
layout suggests that more information can be
acquired if the scene is penetrated more deeply.
An example of a mysterious landscape quality is
a deflected vista, such as a winding trail. Structural
properties that facilitate understanding the
environment are coherence and legibility. Coherence
refers to features that contribute to the
organization, understanding, and structuring of
the landscape image, such as symmetries, repeating
elements, and unifying textures. Finally,
legibility refers to landscape qualities that help
to predict and maintain orientation in the landscape
as one further explores it. Think, for example,
of a prominent rock functioning as an
orientation point.
The Aesthetic Appeal of Natural Contents
In addition to the previous structural landscape
features, the field of environmental psychology
also studies the natural contents that
contribute to the aesthetic qualities of settings:
namely (calm) water features and vegetative
elements. The explanatory framework, again, is
essentially evolutionary. These elements are
liked because they contributed to the survival
and reproduction of early humans. Flowers, for
example, signaled the presence of food sources
and were cues for future foraging sites. They
also helped in differentiating between different
vegetation types, because plants that are not
blooming often look quite similar (Orians &
Heerwagen, 1992). Trees protected against sun
and rain and offered early humans prospects on
the surrounding landscape and retreats from
predators (Appleton, 1975; Orians & Heerwagen,
1992; Summit & Sommer, 1999).
These benefits can explain why vegetative
elements and settings containing vegetation still
cause aesthetic or liking reactions. Different
empirical studies show that individuals consistently
prefer natural, vegetated landscapes over
urban settings without vegetation. When urban
environments are mutually compared, highest
preference is associated with urban settings containing
some vegetation, especially trees, or a water
feature (Smardon, 1988; Thayer & Atwood,
1978; Ulrich, 1986). Such phytophilia is also clear
from the observation that nonnatural environments
(e.g., home and working interiors) often
contain actual vegetative elements or (decorative)
references to natural content (Eibl-Eibesfeldt,
1989; Heerwagen & Orians, 1986). Although empirical
research on preferential reactions toward
flowers is scarce, some studies show that these
elements are indeed associated with positive aesthetic
reactions (e.g., Haviland-Jones, Rosario,
Wilson, & McGuire, 2005; Todorova, Asakawa,
& Aikoh, 2004).
Still, a possible critique of preferential research
into greenery is that when vegetated
landscapes and nonvegetated (urban) architectural
settings are mutually compared, the latter
most often involve representations of quite
modern buildings or at least buildings that are
not very rich in form. However, it can be
pointed out that nature is often characterized by
a typical sort of geometry, or fractal geometry
(see later discussion). This type of geometry
often does not apply to modern buildings or
modern urban settings. A possibility that needs
to be entertained is that the preference for vegetated
scenes is not due to the fact that it is a
natural setting but, instead, that it must (to a
certain extent) be drawn back to the underlying
geometric features of the scene. It would, therefore,
be interesting to compare natural settings
with buildings or urban scenery that emulate a
307ARCHITECTURAL LESSONS FROM ENVIRONMENTAL PSYCHOLOGY
more natural geometry, such as Gothic cathedrals.
(Note that this critique does not undermine
our plea for nature-based, or biophilic,
architecture but instead only strengthens it.)
The Savanna Hypothesis
In habitat theory, savannas are claimed to
be the settings in which early humans spent a
substantial part of their evolutionary history,
and these seem to display an ideal mix of the
previously discussed structural landscape features
and natural contents (Van den Berg,
2004). This type of biome can be broadly
described as low to intermediately complex
settings, having a relatively even and grassy
ground surface dotted with scattered trees or
tree groups. Savannas contain a high degree
of biomass and meat, and these are relatively
easily accessible for terrestrial beings (as opposed
to, e.g., tropical forests). Furthermore,
the openness of savannas facilitates detecting
predators and game and is conducive of
movement and a nomadic lifestyle (Orians,
1980; Orians & Heerwagen, 1992).
The aesthetic preference for savanna-type
landscapes has been the subject of a few
empirical studies. Balling and Falk (1982)
found that young individuals preferred savannas
over other biomes without ever being
exposed to the former type of landscape. The
researchers hypothesize that these findings
could well point to an innate (aesthetic) preference
for savannas (see also: Synek & Grammer,
1998; but see Coss, 2003, for contrasting
findings). Consistent with the savanna hypothesis,
research indicates that people tend
to prefer tree shapes characteristic of highquality
savannas: These typically have a low
trunk, a broad canopy, and a moderate canopy
layering (Orians & Heerwagen, 1992; Sommer
& Summit, 1995). Inquiries into the evolution
of artists’ work (e.g., John Constable) show an
increase of conspicuous savanna features over
time (e.g., opening up views; Heerwagen &
Orians, 1993). Furthermore, studies indicate
that when artificial changes are made to plants
and trees, these increasingly come to resemble
savanna-type vegetation (Heerwagen & Orians,
1993). Finally, areas that are created for recreational
or aesthetic purposes (e.g., parks or golf
terrains) often resemble savannas (Orians,
1980).
Within the field of landscape aesthetics, the
savanna hypothesis is often taken for granted
and has remained mostly undisputed. Nevertheless,
we find it troubling that almost no attention
is paid to discussions in the field of paleoanthropology.
For instance, Wilson (1993) argues
how our preferences for nature, savannas in
particular, are remnants of paleohominid and
early Homo evolution in this type of biome, a
view shared by many in the field of habitat
theory and landscape aesthetics. Yet there is no
consensus on the claim that the savanna is the
unique environment of evolutionary adaptedness.
In his review, Potts (1998) sketches a
more complex view that is supported by scientific
environmental analyses. It evidences that,
during the evolution of early hominids, there
was quite some variation in the environments
that were inhabited, ranging from forests to
savannas to open-canopy woodlands. Still, it
could be countered that the truth value of the
savanna hypothesis does not have any bearing
on the finding that humans adapt to and display
positive affective affiliations with natural environments.
As Kahn (1999, p. 39) points out,
“The evolutionary account can hold, but the
savanna hypothesis needs to give way to a
broader account of genetic predispositions to
inhabited landscapes.”
Naturalness and Stress Reduction
Besides causing liking responses, natural elements
(e.g., vegetation and water features) are
also found to contribute to the restoration of
human individuals. Two major interpretations
of restorative responses have been proposed.
The first, attention restoration theory (ART),
was developed by the Kaplans (e.g., R. Kaplan
& Kaplan, 1989). Essentially, ART interprets
restoration as the recovery of directed attention
or the ability to focus. This capacity is deployed
during tasks that require profound concentration,
such as proofreading or studying. Natural
settings have been found to be ideally suited to
restore or rest directed attention (e.g., Hartig,
Evans, Jamner, Davis, & Ga¨rling, 2003; Hartig
Mang, & Evans, 1991).
The second major interpretation of restoration
is a part of Ulrich’s psychoevolutionary
framework. In this view, restoration applies to a
much broader context than attentional capacities
(e.g., Parsons, 1991; Ulrich, 1993; Ulrich et
308 JOYE
al., 1991). More specifically, Ulrich understands
restoration as stress reduction, and stress
can occur even when directed attention is not
fatigued. Within Ulrich’s model, restorative responses
are explained by the fact that early
humans were often confronted with threatening
and demanding situations (e.g., a predator). As
discussed, such confrontations lead to the quick
onset of negatively toned affective reactions and
corresponding adaptive behavior. Ulrich (1993)
notes that the immediate effects of such responses
are beneficial for the individual. Yet
such reactions also have a certain cost in that
they lead to physiological and psychological
stress (e.g., high blood pressure, feeling depressed).
When the threat has vanished, the
individual is in need of restoration from the
stress that has been caused. The benefits of such
restorative responses are “a shift toward a more
positively toned emotional state, mitigation of
deleterious effects of physiological mobilization
(reduced blood pressure, lower levels of
circulating stress hormones), and the recharging
of energy expended in the physiological arousal
and behavior” (Ulrich, 1993, p. 99). These restorative
responses typically occurred in natural
unthreatening (savanna-like) settings. Such
open, low-risk environments often contained a
(calm) water feature and sometimes had a small
fire. Restoration was also facilitated by the availability
of resources, which reduced stress related
to the uncertainty of finding food (Ulrich, 1993).
The stress-reducing effect of nature is still
effective today because those individuals who
could respond restoratively to stressful situations
survived better. In an often-cited article in
Science, Ulrich (1984) discusses a study of hospital
patients who had undergone gall bladder
surgery and had rooms with views of either a
small tree group or of a brown brick wall. As
opposed to patients with the brick wall view,
patients with the tree view had shorter hospital
stays, received fewer negative comments from
the nurses, required less moderate and strong
analgesics, and had slightly fewer postoperative
complications. (For further research into the
relation between stress reduction and nature,
see, e.g., Custers, 2006; Hartig et al., 2003;
Parsons, Tassinary, Ulrich, Hebl, & GrossmanAlexander,
1998; Ulrich, 1981; Ulrich et al.,
1991).
The Value of Nature-Based, or Biophilic,
Architecture
Although there is solid empirical evidence
that humans hold positive affiliations with a
specific set of landscapes and natural elements,
this does not preclude that some natural features
or occurrences also cause more negative and
even aversive reactions in humans (e.g., Mineka
& O¨ hman, 2002; Van den Berg & ter Heijne,
2005). Another issue is that the experimental
outcomes are sometimes difficult to integrate
into a coherent, overarching conceptual framework.
For example, what is the relation between
abstract structural landscape features and the
preference for water elements? Other issues are
that differences in nature appreciation are often
left in the dark in these discussions (but see Van
den Berg, 2004), and it is still a matter of debate
in which sense the genetic component of these
(positive) affiliations should be understood
(Cummins & Cummins, 1999). Still, whatever
the outcome of these matters, the general picture
emerging from the previous concise review
is that humans have a (partly) hardwired emotional
affiliation with certain classes of natural
objects. Some researchers have argued about
the affective relation with natural elements and
landscapes in terms of biophilia (e.g., Kellert &
Wilson, 1993; Wilson, 1984). Although the theoretical
merits of this term have been questioned
(Joye, 2007), in the remainder of this
report the notions biophilic and biophilia will
nevertheless be used as synthetic concepts.
The occurrence of biophilic responding
stands in sharp contrast with the observation
that there is increasingly less contact with nature
in Western technologically oriented societies.
Wolff, Medin, and Pankratz (1999) found
that such an evolution has nontrivial effects on
cultural expressions of nature. In particular,
they made a historical study of word use in
dictionaries and found that, from the 20th century
onward, the use of (folk)biological terms
devolved, and their application lost precision. In
contrast, several nonbiological terms evolved
during this period (e.g., books, clothes, furniture).
Apart from being associated with an impoverishing
conceptual framework for natural
objects, it is also plausible that reduced contact
with nature can be accompanied by a reduced
knowledge of the rich variety of forms characteristic
of natural entities. A probable artistic or
309ARCHITECTURAL LESSONS FROM ENVIRONMENTAL PSYCHOLOGY
creative consequence is that the formal curriculum
of artists and architects becomes narrower.
The reason is that natural form can be
considered as a creative or compositional grammar,
which can be used for creating artwork, or,
as Stephen Kellert put it, “The aesthetics of
nature can function as a kind of monumental
design model” (Kellert, 1997, p. 36). The loss of
this monumental design model has its architectural
counterpart in modern urban settings,
which are increasingly governed by euclidean
geometry and stripped of ornament, patterning,
detailing, and color (Salingaros, 2004). Architectural
references to nature can help put an end
to this uniformity. By encouraging architects to
integrate natural forms and patterns in their
work, they are motivated to study nature’s
shapes and compositional rules, and this can
enrich their creative curriculum.
Besides having creative consequences, reduced
contact with natural form could also subtly
influence the way in which people think
about the world. Inquiries into semantic memory
indicate that processing conceptual information
about living things mainly relies on perceptual
information (e.g., the concept “zebra”
activates perceptual information, such as
“stripes”), whereas processing nonliving things
or artifacts depends on functional information
(e.g., the concept “knife” activates functional
information, such as “cutting”; e.g., Crutch &
Warrington, 2003; Farah & McClelland, 1991).
These findings could have important implications.
The presence of nonnatural things, and
especially artifacts (e.g., cell phones, computers,
chairs, pots, printers), is ever increasing in
the human living environment at the expense of
natural structures or entities. A probable consequence
is that neural areas related to an object’s
functionality and hence functional analyses
(i.e., how an object should be used or manipulated)
are becoming increasingly more dominant
in our thinking about the constituents of the
modern living environment. As we become
more acquainted with such thinking, it is not
implausible that it will be deployed in other
domains as well (e.g., to generate explanations).
This could especially occur when knowledge
about phenomena in a certain domain, such as
the natural world, becomes increasingly more
scarce or more underdeveloped.
Although functional postures are important
and necessary in certain fields, transferring
them to other domains or contexts can prove
problematic and harmful. Today, we can witness
how thinking about nature and natural resources
in terms of things that can be manipulated
has devastating effects. The upshot is that
this shifts the balance even further toward functional
thinking, because nature is replaced by
entities that predominantly require functional
analyses. Probably, this process can be countered
by extensive contact with the natural
world, and developing a rich conceptual framework
about it (e.g., by nature education). This
could help people realize that functional thinking
is not always desirable with regard to nature.
While being more speculative, it can be
hypothesized that integrating naturalistic elements
in architecture can counteract the increasing
dominance of functional semantic networks
and the associated epistemological attitude. Admittedly,
people will not consider biophilic architecture
or design as actual nature. However,
such architecture shares some essential formal
features with living things, and research indicates
that perceptual features are important for
recognizing living things. Biophilic design
could lead to more attentiveness to an object’s
perceptual qualities, thereby leading attention
away from its possible functions and the associated
functionalist postures. Furthermore, because
of the (hardwired) emotional affiliation
with certain natural elements, nature-based architecture
can awaken fascination for natural
forms. Such an attitude could be ecologically
relevant, because it is found that proenvironmental
behavior is positively influenced by emotional
states toward nature (Kals, Schumacher, &
Montada, 1999).
Without a doubt, people can get used to less
formal diversity in the built environment. However,
such a situation is not desirable because an
increasing dominance of uniform (modernist)
environments will probably have a number of
psychological and physiological costs. Recall
how, under evolutionary pressures, natural
forms and environments became associated
with a broad range of emotions, ranging from
fear to excitement. In the human ancestral
world, such associations promoted fitness because
they motivated the organism to undertake
adaptive reactions (e.g., flight). Today, there
seems to be a discrepancy between the habitats
humans have evolved in and modern urban settings.
For example, it was already noted that the
310 JOYE
former was characterized by, among others, a
mix of complexity and order (S. Kaplan, 1987,
1988; Ulrich, 1983). Yet current architectural
settings do not appeal to this ordered complexity.
Modernist architecture mainly consists of
simple volumetric forms and thus deprives the
senses in their constant search for meaningful
information. On the other hand, postmodern and
deconstructive architecture deliberately destroy
architectural coherence, either by jumbling
together disparate stylistic and formal elements
or by placing the destruction of coherence
and structure at the heart of the tradition
(Salingaros, 2004). Furthermore, modern building
is often dictated by efficiency and economic
motives, barely leaving room for symbolic and
stylistic references to natural contents (e.g., ornament;
Pinker, 2002; Salingaros, 2004). In
short, much of the modern built environment
fundamentally lacks (references to) the contents
and structural organization that are characteristic
of a good habitat. Exposure to such environments
could rapidly and automatically trigger
negatively toned feelings and the associated
stress-related endocrinal reactions (Ulrich,
1983). Although such responses could go by
largely unnoticed because of human habituation
to this type of environment, the long-term occurrence
of such stress reactions could have
important health effects (Parsons, 1991).
Increasing urbanization undoubtedly has a
number of positive consequences. For example,
in modern cities, people come to live closer
together, which could promote social interaction
and the pleasure and enjoyment associated
with this (Van den Berg, Hartig, & Staats,
2007). Furthermore, there is nothing inherently
wrong or undesirable about modern building
styles, and there is no reason to doubt the genuineness
of positive reactions to such buildings.
What, according to the current argument, could
become problematic is the (growing) dominance
of such nonnatural building styles at the
expense of settings with natural form languages
(albeit natural or artificial ones). The core argument
of the current study is that, by including
elements of ancestral habitats in the built environment,
one can counter potential deleterious
effects, which stem from this dominance, resulting
in more positive affects and more relaxed
physiological and psychological states. In the
remainder of this article, such architectural interventions
are denoted as nature-based, or biophilic,
architecture.
Integrating Structural Landscape Features
in Architecture
How can the structural landscape features,
discussed earlier, be meaningfully applied to the
built environment? This is a more difficult issue
than applying well-defined natural contents to
architecture, because the former features are of
a more abstract nature. Furthermore, only very
few researchers have addressed this issue and
proposed clear guidelines on how to successfully
integrate these qualities in architectural
settings.
First, turn to the type of setting that contains
an ideal mix of these structural landscape features,
namely the savanna. An evident strategy
to imitate savannas is to integrate photographs
or projections of savannas in (interior) spaces.
Another, more architectural method consists of
mimicking key structural features of savannas.
Possible strategies include creating wide and
open spaces; making variations in the architectural
topography; integrating clusters of real or
symbolic trees (e.g., columns); and integrating a
water feature (e.g., a fountain) or even a small
fire. Note how certain retail settings, such as
shopping malls, often contain these elements.
Because a major goal of the retail sector is
attracting people, it should be no surprise that
organizational features of preferred settings are
(intuitively) deployed in such commercial contexts
(Heerwagen, 2003).
Because of their openness, savannas provided
good prospects on the surrounding area. Furthermore,
trees typical of savannas (acacias)
have low trunks and could, therefore, be
climbed to see across the landscape and to escape
predators. On the other hand, the broad
canopies provided good protection against sun
and rain. Grant Hildebrand (1999) uses Appleton’s
(1975) notions of prospect and refuge as
explanatory principles for the aesthetic appeal
of certain buildings. Although Hildebrand does
not provide exact guidelines, his analyses show
which spatial organizations influence the prospect
and refuge dimensions of buildings. With
regard to Frank Lloyd Wright’s house in Taliesin,
Wisconsin, Hildebrand notes the following:
“Deep overhanging eaves, alcoves and recesses,
the withdrawal of the house in the dense foliage,
311ARCHITECTURAL LESSONS FROM ENVIRONMENTAL PSYCHOLOGY
and the cave-like masses of stone anchoring the
house to the hill all convey that this is a haven
within which one can withdraw secure. Extensive
bands of window and the balcony reaching
out over the falling landscape, moreover, indicate
that the advantages of generous prospect
are likely to be available within” (p. 28). It is
clear that feelings of prospect and refuge can be
evoked by specific architectural interventions.
Strategies for evoking concealment are reducing
lighting conditions, lowering ceilings, and
making small windowless spaces enclosed by
thick walls. The prospect dimension depends on
opposite characteristics: larger space dimensions,
raised ceilings, thin transparent walls,
wide views on surrounding spaces, building on
an elevated site, increased lighting conditions,
balconies, and so on.
Prospect and refuge can be linked to the
predictors complexity and coherence, central to
the Kaplans’ preference matrix (e.g., R. Kaplan
& Kaplan, 1989). Only a setting that contains
enough prominent landscape features (e.g.,
trees, rocks) can provide opportunities for refuge.
On the other hand, if a setting contains too
many elements, this makes it difficult to have a
clear view over the landscape. Although complexity
and coherence have primarily been applied
to landscapes, there is empirical evidence
that a balanced presence of both properties contributes
to the aesthetic qualities of built settings
(e.g., Herzog, Kaplan, & Kaplan, 1982). However,
how can a complex set of architectural
elements be ordered? Again, take a look at the
architectural tradition associated with Frank
Lloyd Wright, namely organic architecture. In
essence, organic architecture is not restricted by
stylistic conventions but is characterized by an
inherent form freedom. Although not necessary,
this often translates in buildings that are quite
irregular and complex both in plan and elevation.
Yet organic architects often use a geometric
module (e.g., a triangle) as main compositional
element (Mead, 1991). In this way, different
parts of the building are given a similar
form, which results in an overall coherence
(Eaton, 1998).
It could be noted that merely repeating similar
elements does not guarantee an ordered
complexity. On the contrary: It can even lead to
random structures, as in deconstructivism. A
possible solution is to organize these (similar)
elements through patterns. These are often the
result of only a few simple mathematical operations,
such as reflectional, rotational, translational,
and glide symmetries. More complex
patterns are obtained when these symmetries are
repeated or when they are nested (Salingaros,
2003; Figure 1A–D). Traditionally, patterns
take in a prominent place within the organic
tradition. Historically, they can also be found in,
for example, tiling, ornaments, mosaics, stained
glass windows, and (oriental) carpets.
Another structural feature that positively correlates
with landscape selection is mystery.
Some claim that this property can be conveyed
by specific design elements: “When appearing
around corners, attached to walls, and hung
from ceilings, interesting objects, architectural
details or motifs, graphics, video displays and
artifacts can create a little mystery and surprise
in the workplace” (Hase & Heerwagen, 2000, p.
30). However, the most straightforward way to
apply mystery to an architectural setting is by
deflected vista. This can be realized by letting
the architectural trail (e.g., corridor) bend away,
which can lead to curiosity of what might lie
beyond the bend, thereby encouraging explorative
behavior. Another mode of mystery is
called “enticement.” Essentially, this notion refers
to the situation in which a person is in the
dark, from where it can see a partially visible
Figure 1. Patterns can be obtained by some simple mathematical transformations (Salingaros,
2003): (A) randomness; (B) translational symmetries; (C) reflectional symmetries; (D)
rotational symmetries that are nested. (Copyright © Yannick Joye.)
312 JOYE
and enlightened area or setting. Such enlightened
regions draw attention and trigger explorative
behavior. Although mysterious settings
can be aesthetically appealing, too much irregularity
or surprise can have the result that the
layout of the building becomes confusing and
nontransparent, ultimately leading to orientation
and way-finding problems. Legibility can be
enhanced by integrating signalizations and distinctive
markings, by offering views on the outside,
and by making the building shape more
regular (Evans & McCoy, 1998).
Imitating Natural Contents in Architecture
How could natural contents be integrated into
the built environment? Evidently, this can be
done by providing views on the outside environment,
by integrating vegetation in built settings,
by hanging nature pictures on the wall, by
nature-oriented screensavers, and so on. These
interventions are what Stephen Kellert (2005)
called indirect experiences of nature, and they
come quite close to the design interventions
from the field of evidence-based design (Ulrich
& Zimring, 2004; Van den Berg & Van WinsumWestra,
2006). It is in this sense that the modern
built environment sometimes imports some of the
icons of habitability that are typical of ancestral
habitats. The result is that even architecture that is
characterized by nonnatural forms can be consistent
with the current argument. For example, some
modernist architecture (e.g., Mies’s Farnsworth
House) is characterized by large expanses of glass,
by which the building opens up to the surrounding
natural landscape, potentially causing biophilic responses
in the inhabitants.
Implanting a building in a natural landscape
does not necessarily tell us something about the
architectural form and whether it in some sense
displays key features of our ancestral habitats.
Because we factually inhabit contexts in which
buildings are often more dominant than nature,
it also becomes relevant to come to biophilic
interventions that pertain to the architectural
form. But how should such interventions be
conceived? A first strategy is to architecturally
imitate preferred natural entities, such as vegetative
elements. Such imitations can take on
different levels of abstraction. A first option is
to literally copy these elements in architectural
design. As already noted, there is an age-old
tradition to copy nature, especially floral and
vegetal patterns, in traditional ornament. Admittedly,
it could be possible that such imitations
will not be very successful, because the
associated emotional states could quickly be
followed and suppressed by higher order or
cultural beliefs. For example, the architectural
community could consider such imitations as
kitsch. Nevertheless, it should be noted that
there is often a discrepancy between what is
found appealing by experts and laypersons. The
primary goal of this study is not to argue for
what is supposedly fashionable or to defend
high art but to indicate what could be psychologically
appealing for the broad public.
An alternative to literal imitations is to create
architectural designs based on schematic imitations
of natural elements. These would no
longer be exact copies but artistic interpretations
that still contain some global visual similarities
with regard to the original natural object.
One of the central claims of the current study is
that such constructions will be accompanied by
affective states that are similar to those evoked
by real natural contents. Orians and Heerwagen
(1992, p. 572) expressed it as follows: “An
evolutionary-ecological approach to aesthetics
suggests that the incorporation of trees and tree
forms, actual or symbolic, into the built environment
should have a strong positive impact
on people. . .We predict that the presence of
these ‘symbolic trees’ is associated with positive
response to built environments.”
Although the occurrence of biophilic responses
to symbolic representations of nature
could be prima facie plausible, it is problematic
that it is often taken for granted in the literature
on biophilic architecture. Although research
that has directly tested this prediction is lacking,
some indirect arguments can be presented that
support the conclusion. First, it is evident that
domain-specific mechanisms in the brain will
be activated by the objects in which they are
specialized. For example, a face detection
mechanism will be activated by its proper input:
actual human faces. Yet it seems that such domain-specific
mechanisms do not care about
whether the objects it analyzes are in any sense
real or symbolic. More specifically, these neural
areas also tend to become activated by elements
that share some central geometric features with
the proper input of the domain-specific systems.
This is one reason why a symbolic representation
of a face, such as, for example, a smiley
313ARCHITECTURAL LESSONS FROM ENVIRONMENTAL PSYCHOLOGY
face ( ) or the front of a car, can be perceived
as having facelike features (Pinker, 1997; Sperber
& Hirschfeld, 2004) and can lead to the
onset of similar emotions as real eyes or faces
(e.g., Aiken, 1998a). Similarly, it is probable
that the neural mechanisms specialized in processing
natural elements will also be activated
by stimuli that share essential geometric features
with natural elements, such as symbolic or
imitative representations of nature in architecture.
Because of the importance of quickly displaying
adaptive behavior to natural stimuli
(e.g., exploration, escape, fighting), it is probable
that at the early stages of processing some
affective processing or priming will already
take place, before any conscious recognition of
the imitated natural elements occurs (Ulrich,
1983).
Further reasons why architectural imitations
of nature could trigger biophilic responses are
more empirical in nature. First, it can be pointed
out that research on environmental preferences
often uses simulations of nature (e.g., photos,
posters, videos, and even paintings). The results
that are obtained with these stimuli are close to
the responses associated with real nature, which
suggests that realness does not play a decisive
role. (Yet it should be noted that in such contexts
nature is mostly depicted very realistically,
and when only realistic representations of nature
can be used in architecture, this restricts the
range of possible architectural interventions almost
exclusively to ornamentation). Second,
symbolic representations of nature have been
used throughout the history of art for aesthetic
enhancements, which suggests that these can
trigger biophilic responses. Third, research indicates
that preferences for natural settings can
be statistically predicted by underlying geometric
characteristics, which lends plausibility to
the claim that geometric abstractions from nature
can cause the associated affective effects
(Ha¨gerha¨ll, Purcell, & Taylor, 2004; see also
Fractals and Biophilic Reactions: A Critical
Evaluation section).
There is a further important reason why symbolic
or schematic interpretations of naturalness
can lead to aesthetic reactions. This conclusion
is based on the finding that formal abstractions
or simplifications of certain conspicuous traits
of (survival-relevant) stimuli lead to similar,
or even stronger, emotional responses as the
original (natural) stimulus. Within the field
of ethology, such stimuli are labeled “supernormal
stimuli” (Tinbergen & Perdeck, 1950).
Ramachandran and Hirstein (1999) argue how
this phenomenon is one of the central laws that
artists (unconsciously) deploy in art. They clarify
this principle by referring to a phenomenon observed
in the field of animal discrimination,
namely the peak shift effect. A rat that is taught to
discriminate between a square and a rectangle and
is rewarded for discriminating the rectangle will
respond more frequently to the rectangle. However,
when the original rectangle is elongated, the
rat will respond even stronger to this new rectangle
than to the rectangle that it was taught to
discriminate. According to Ramachandran and
Hirstein (1999), artwork often taps a similar effect:
“What the artist tries to do (either consciously
or unconsciously) is to not only capture
the essence of something but also to amplify it in
order to more powerfully activate the same neural
mechanisms that would be activated by the original
object” (p. 17). According to Ramachandran
and Hirstein, such amplifications can occur along
different dimensions of the artistic work: for example,
form, color, and movement (see also
Aiken, 1998b). It is clear that, in the present discussion,
main interest goes to amplification of the
architectural form, which can cause a peak shift
effect with regard to real natural forms.
Maybe the most well-known examples of architecture
in which schematic interpretations of
natural forms are present have been created by
Antonı´ Gaudı´. For example, the interior columns
of the Sagrada Familia are quite similar to
treelike and flowering structures (Figure 2A–B).
Indeed, one can clearly differentiate a stem,
which bifurcates into further branches and subbranches.
The canopy of these treelike structures
consists of flowering forms, which further
strengthens the impression of symbolic vegetation.
A more modern architect whose work also
contains schematic interpretations of natural objects
is Santiago Calatrava. Like in Gaudı´’s
work, structural forces are an important determinant
of the shape of Calatrava’s architecture.
Yet he also seems to be directly inspired by the
shapes of nature. According to Von Moos, “His
architecture relates to the morphologies of plant
and animal life—on land, in the depth of the
sea, or in imagination” (Tischhauser & Von
Moos, 1998, p. 338). Particularly relevant for
the present discussion is that several building
elements resemble vegetative structures. For in-
314 JOYE
stance, both Calatrava’s Orient Station (Lisbon)
and his BCE Place (Toronto) could be interpreted
as “‘forests’ of structural ‘trees’” (Tzonis, 1999, p.
82; Figure 3).
Applying Nature’s Fractal Geometry to
Architecture
What is a fractal? Are there any good reasons
to go beyond the imitation of natural contents?
Is there something about the outlook of
nature that can be abstracted away and applied
to architecture while still giving rise to biophilic
reactions? We hinted at this already and speculated
that the underlying (fractal) geometry of
natural scenes is perhaps a contributing factor to
aesthetic and stress-reducing responses. Some
scholars adhere to similar ideas. Katcher and
Wilkins (1993) note that it would be valuable to
“search for general characteristics of the patterns
in nature that produce relaxation. Exploring
the ability of computer-generated fractal
structures to entrain subjects’ attention and induce
calm could be a promising approach, as
well, since waves, flames, and clouds can be
duplicated by fractals. Fractal structures could
also relate the physiological and cognitive effects
of both natural phenomena such as waves
and cultural artifacts like music” (pp. 177–178).
Similarly, Purcell, Peron, and Berto (2001)
speculate that the high restorativeness of natural
scenes could be due to their fractal characteristics,
whereas built environments are low in restorativeness
because of their underlying euclidean
geometry.
Fractal geometry has been described and explored
since the 1970s (Mandelbrot, 1977). The
term fractal is derived from the Latin word
fractus, meaning broken or fractured. One of the
defining features of a fractal is that this roughness
recurs on different scales of magnitude
(Figure 4). When zooming in on a fractal, at
each magnification a structure appears that is
more or less similar to the global form of the
fractal, a property labeled “self-similarity.” Another
feature that plays an important role within
the field of fractal geometry is the concept of
dimension. In euclidean geometry, lines have a
dimension of one, whereas geometric objects,
such as squares and triangles, have a dimension
of two, and volumes in space are three dimensional.
In contrast, the dimension of a fractal, or
the fractal dimension, is not an integer value.
For fractals in the plane, the fractal dimension
lies between the first and the second dimension,
which gives a value between 1 and 2
(e.g., 1.46). For fractals in space, the fractal
dimension lies between 2 and 3 (Voss, 1988).
Essentially, these noninteger values are due to
the fact that fractal patterns have a very wrinFigure
2. The interior of Gaudı´’s Sagrada Familia contains schematic interpretations of
natural contents. Left: columns as treelike structures. Right: flowerlike canopies. (From
Guillaume Paumier. Used with permission).
315ARCHITECTURAL LESSONS FROM ENVIRONMENTAL PSYCHOLOGY
kled character and, therefore, occupy more
space than a simple line (first dimension) but do
not fill the entire plane (second dimension). In
essence, the fractal dimension should be interpreted
as a measure of the degree in which
(similar) detail recurs on different scales of
magnitude. Hence, the concept could be understood
as a measure of complexity.
Fractals, naturalness, and liking responses.
Is there any evidence for the claim that fractal
characteristics could as well be associated with
biophilic responses to typical natural contents,
such as vegetation? In other words, why could
fractal geometry be an important beneficial ingredient
of natural scenes? First, there is a profound
link between the shape of many natural
structures and fractals. In essence, the former
are fractal-like in that they often display the
self-similarity that is so typical of fractals. Evident
examples are trees, mountains, lightning,
clouds, coastlines, and so on. A second link
between fractals and nature is the observation
that natural elements can be elegantly mimicked
with fractal geometry. For example, plants and
trees can be straightforwardly generated by
fractal procedures, such as L-systems (Prusinkiewicz
& Lindenmayer, 1990). Perhaps the
most well-known fractal model of vegetative
elements is the Barnsley Fern (Peitgen, Ju¨rgens,
& Saupe, 1992), which was discovered by
Michael Barnsley. A third way in which fractals
and nature can be related is more psychological
in nature. Apparently, fractal patterns evoke
associations of naturalness in human subjects
(Geake, 1992). Closely related is the finding
that contact with fractals improves the ability to
perceptually differentiate between highly similar
natural patterns (Geake, 1992).
Not only are fractals perceptually related to
naturalness, but their aesthetic value is also obvious
to many. These rich and sometimes colorful
images often provoke awe and fascination
in viewers. It should, therefore, be no wonder
that some artists (e.g., Jackson Pollock) have
(unconsciously) deployed fractal principles in
their work to reach an aesthetic effect (Mureika,
2005; Taylor, 2002). Still, these connections
between aesthetics and fractals are only anecdotal
and intuitive. In search for a stronger
foundation for fractal aesthetics, reference can
be made to preliminary empirical research by
Richard Taylor (1998). Taylor mentions that
Figure 3. The “forest of trees” in Calatrava’s Orient Station. (From Inge Kanakaris-Wirtl;
www.structurae.de. Used with permission.)
316 JOYE
more than 90% of a group of 120 students
preferred fractal patterns over nonfractals. Yet it
should also be noted that Arthur Stamps (2002)
has tested this conclusion more rigorously and
did not find that fractal patterns were aesthetically
preferred over nonfractals. Nevertheless, it
should be pointed out that Stamps used fractal
contours, and the self-similarity was not readily
perceivable in the representations.
Other research into fractal aesthetics has
mainly focused on the relation between fractal
dimension and aesthetic preference. One of the
first empirical studies of this relation has been
carried out by Aks and Sprott (1996). The experiment
revealed that 24 study participants
preferred fractal patterns with a fractal dimension
of between 1.17 and 1.38. The average
fractal dimension of the most preferred attractors
was 1.26 Ϯ 0.06. Spehar, Clifford, Newell,
and Taylor (2003) used three different categories
of fractal patterns (mathematical fractals,
natural fractals, and fragments of Pollock paintings)
and found that patterns with a fractal dimension
of between 1.3 and 1.5 were preferred
most, as opposed to patterns with dimension
values between 1.1 and 1.2 and between 1.6
and 1.9. Abraham et al.’s (2003) study revealed
a nonmonotonous relation between aesthetic
preference and fractal dimension. Patterns with
the highest and lowest fractal dimension were
least preferred, whereas those with a midrange
fractal dimension were liked most. More specifically,
attractors with a fractal dimension
ranging from 1.4 to 1.6 (mean fractal dimension
of 1.54) received the highest preference ratings.
Although these results need further replication
and are to be treated with caution, there is
a tendency to prefer patterns with an intermediate
fractal dimension, ranging from about 1.3
to 1.5. Note that there are some further hints for
the special status of this range of values. For,
example Rogowitz and Voss (1990) found that
recognizing and finding new shapes in fractal
patterns is best for those patterns with a fractal
dimension ranging from 1.2 to 1.4. Geake and
Landini (1997) found that the variance in study
participants’ judgments of the complexity of
Figure 4. A typical fractal pattern. This is a detail of the Mandelbrot set.
317ARCHITECTURAL LESSONS FROM ENVIRONMENTAL PSYCHOLOGY
fractal patterns exploded when pictures had dimension
values greater than 1.3.
Fractals and stress reduction. If fractals
can be meaningfully related to aesthetic reactions,
then is there any way in which these
patterns can be linked to the capacity of natural
contents to reduce stress (e.g., Ulrich et al.,
1991)? To answer this, it must first be noted that
there are reasons to assume that restorativeness
is the underlying factor for aesthetic reactions
toward natural settings. Van den Berg, Koole,
and van der Wulp (2003) have experimentally
confirmed this hypothesis by performing
[m]ediational analyses. . .[which reveal] that affective
restoration accounted for a substantial
proportion of, the preference for the natural
over the built environments (p. 135).. How can
this finding be related to the field of fractal
aesthetics? A plausible answer is that if fractal
characteristics underlie aesthetic responses to
natural settings to a certain extent, and if these
responses are maximal for an intermediate fractal
dimension, then it could well be that this
range of values will also have the highest restorative
potential.
Wise and Taylor (2002; see also Taylor et al.,
2005) have carried out a preliminary study to
test the relation between fractal geometry and
stress reduction. They reexamined a study performed
by Wise and Rosenberg (1986) involving
24 individuals who were continuously exposed
to four different patterns: a photograph of
a forest setting, a simplified representation (i.e.,
painting) of a savanna landscape, a picture with
squares, and a white plane, which functioned as
a control picture. While being exposed to the
images, participants had to undergo three stressful
mental tasks: an arithmetic task, solving
logical problems, and creative thinking. Between
every task there was a 1-min recovery
period. Physiological stress was determined by
skin conductance, because research indicates
that increased conductance correlates with
higher levels of stress.
It was found that the degree of physiological
stress was dependent on the type of pattern that
was presented to the participants. Because naturalness
is found to be a predictor of aesthetic
and restorative responses, one would expect that
the picture of the forest setting was most effective
in reducing stress (indeed, it looked the
most like real nature). Contrary to this expectation,
this effect was most effectively produced
by the unrealistic painting of the savanna landscape.
The change in conductance between
work and rest periods was 3% lower for the
forest photograph and 44% lower for the savanna
representation than for the control picture.
This means that these pictures dampened
(physiological) stress associated with the tasks.
Because the researchers did not expect this
outcome, they decided to determine the fractal
dimension of each of the pictures. Only the
forest and savanna pictures had fractal characteristics.
It was found that the pattern that was
most effective in stress reduction, the savanna
picture, had a fractal dimension that fell within
the range of dimension values that was earlier
found to correlate with highest aesthetic preference
(Spehar et al., 2003). Because this picture
is only a rough and simplified representation of
a savanna, the authors speculate that the depiction
of natural contents alone cannot be a sufficient
condition for a restorative effect. If this
were the case, then highest restorativeness
should be expected to come from the more
realistic and naturally looking forest setting.
Instead, it seems that, besides depicting natural
elements, the scene should also have a specific
fractal dimension in order to maximize stress
reduction. Specifically, from this experiment, it
can be tentatively concluded that its dimension
value should fall within the range of 1.3 to 1.5.
Despite these remarkable results, some questions
still remain. First, of course, is the preliminary
character of these experimental outcomes,
which necessitates replication. Second, the literature
on habitat theory (e.g., Orians, 1980)
claims that humans are innately predisposed to
prefer savannas because it is the biome in which
they thrived for a substantial part of evolutionary
history. Consequently, it could be argued
that it is quite natural that the savanna picture
leads to the highest restorative responses. Thus,
it remains unclear whether it is the fractal dimension
that underlies these responses or the
specific contents depicted in this image. Perhaps
the same experiment should be replicated with
fractal patterns, devoid of meaningful representative
contents. Again, however, note that
Ha¨gerha¨ll et al. (2004) found that preferences
for settings could be predicted by the fractal
dimension. This adds support to Taylor’s claim
that it is the fractal component that underlies the
restorative responses, not only the depicted contents.
Yet it could also be pointed out that
318 JOYE
features such as bodies of water are highly
preferred contents (Ulrich, 1983) that cannot be
straightforwardly analyzed in terms of fractal
geometry. Perhaps something similar applies to
the savanna painting. For example, the typical
shape of savanna trees (low trunk, broad
canopy) could be a highly preferred icon in
landscapes. Perhaps it is a basic “preferendum”
(Ulrich, 1983), which is irreducible to fractal
characteristics. It can also be argued that the
stress-reducing character of fractals is already
established. The reason is that certain fractals
are sometimes very difficult to distinguish from
real natural elements (e.g., the Barnsley Fern). It
is, therefore, very probable that such naturalistic
fractals will lead to biophilic responses. A lot of
natural entities are fractal, and the main difference
with mathematical fractals is that their
self-similarity does not extend to infinity.
The affective value of fractals. The affective
value of fractal patterns can be explained by
the finding that naturalness is a predictor of
biophilic responses and by the fact that fractal
geometry eminently captures this quality.
Sometimes it is even claimed that the aesthetic
effect of fractals is due to the fact that such
patterns lead to a peak shift effect (Ramachandran
& Hirstein, 1999), because they imply an
exaggeration of the dimension of recursiveness,
which is a characteristic quality of natural form
(Joye, 2007; Mureika, 2005). However, what
could be the explanation for the preference for
fractal patterns with low to intermediate dimension
values and for their restorative potential?
Because Cutting and Garvin (1987) have discovered
a correlation between the fractal dimension
and complexity of fractal patterns, a possible
answer is that the fractal dimension offers
a quick cue of the complexity of a scene. Complexity
is a predictor of habitat quality (S.
Kaplan, 1987, 1988), and the preference for a
low to intermediate fractal dimension could be
rooted in the fact that habitats of a low to
intermediate complexity (e.g., savannas) offered
the best chances for survival (Wise &
Taylor, 2002). Indeed, in such settings, information
can be quite easily grasped and processed,
as opposed to more complex environments
(e.g., tropical forests). This reduces the
possibility that crucial information (e.g., predators)
will be missed or ignored. On the other
hand, the complexity is high enough to keep one
interested, to awake further explorative behavior,
and to provide opportunities for refuge. It is
quite probable that the presence of these properties
facilitated restoration, hence the restorative
responses associated with patterns of an
intermediate fractal dimension (Taylor et al.,
2005). For example, resting from stressful or
demanding events seems more likely to occur in
settings that offer retreats but that also contain
enough openness, which reduces the probability
that one will be attacked by a predator by surprise
(Ulrich, 1993). If specialized neural mechanisms
exist that assess the quality of a habitat,
then it is not too difficult to suppose that these
compute the fractal dimension in order to have
a rapid cue of habitability.
It should be noted that sometimes the aesthetic
appeal of fractal-like patterns is also explained
by the fact that the nervous system is
governed by fractal-like processes. In particular,
Anderson and Mandell (1996, p. 114) argue
that human evolution in a fractal world has
required “the incorporation of fractal structures
as well as fractal processes, and these in turn
would be integrated into sensory systems, recognition,
memory, and adaptive behaviors.”
More specifically, the authors describe how human
functioning is characterized by a fractal
noise signal—1/f noise—from the microscopic
level of neural functioning to the macroscopic
level of human behavior. For the present discussion,
the presence of this type of noise in the
human mind and brain seems especially relevant:
“In neurobiology in general, and neurophysiology
in particular, 1/f patterns in time are
profound in their recurrent appearance across
many levels of organization in the nervous system,
from the underlying cellular dynamics of
ion channels and intermittent firing patterns of
neurons to developmental phenomena occurring
during the organization of breathing to global
dynamics in the nervous system such as subcortical,
transcortical and scalp EEG defining behavioral
states of consciousness” (Anderson &
Mandell, 1996, p. 77). Some authors propose
that, because of its fractal nature, the brain is
optimized to process the statistical characteristics
of natural scenes, which are also found to be
governed by 1/f spectra (e.g., Knill, Field, &
Kersten, 1990). For instance, Gilden, Schmuckler,
and Clayton (1993) found that discriminating
fractal contours was best for those sharing
(statistical) properties with natural scenes. Consistent
with this is the finding that neurons in the
319ARCHITECTURAL LESSONS FROM ENVIRONMENTAL PSYCHOLOGY
V1 area of the brain show a preference for 1/f
signals (Yu, Romero, & Lee, 2005).
Some authors hypothesize that the proposed
fractal nature of the human mind/brain can illuminate
the creation of fractal artwork. Essentially,
such art should be understood as an exteriorization
of the fractal aspects of brain functioning
(Goldberger, 1996). However, what
does such an account have to say about the
aesthetic value of fractals? Different authors
have described the perception of such fractallike
patterns in terms of a resonance between
the fractal character of basic perceptual processes
and the characteristics of the perceived
pattern, or as Goldberger (1996) put it, “The
artwork externalizes and maps the internal
brain-work. . .Conversely, the interaction of the
viewer with the artform may be taken as an act
of self-recognition” (p. 102). Yet it is difficult to
see how a resonance between the perceiver and
the perceived can explain the aesthetic experience
that is often associated with these images.
What can an objective description in terms of
noise signals tell us about subjective aesthetic
experiences? Another critical point is that the
explanation of biophilic responses toward fractals
in terms of noise signals emitted by the
nervous system must be situated on a different
level than the evolutionary account presented
here. The former explanation refers to the workings
of the nervous system, but it does not
explain why it is characterized by 1/f noise in
the first place. Although it is true that some
researchers believe it is the result of evolution in
a natural world with similar fractal properties
(Anderson & Mandell, 1996), it remains unclear
how a connection with our evolutionary framework
should be conceived precisely. In fact, 1/f
noise occurs on all levels of human functioning,
from human gait dynamics to neural functioning,
whereas in our account it is proposed that
the affiliation with natural form has its correlate
in more discrete brain mechanisms.
Fractals and biophilic reactions: a critical
evaluation. The previous review shows that
there is convincing evidence that fractals capture
some of the core geometric qualities of
natural structures. Furthermore, there is also
some support, both intuitively and empirically,
that biophilic responses are associated with
some typical fractal qualities (i.e., their degree
of recursiveness). Still, this does not necessarily
entail that it is the naturalness associated with
fractals that is the underlying cause of these
responses. Notwithstanding that this is perhaps
the most obvious explanation, it could be
equally hypothesized that fractals are quite
complex patterns that give us the necessary
degree of arousal that our visual apparatus desires.
Such an explanation does not rule out the
fact that fractals look natural, but it makes no
recourse to naturalness to explain our emotional
relation with such patterns.
It is clear that further research is needed on
the topic of fractal aesthetics and the possible
relations to biophilia. In this regard, it is interesting
to note that some empirical research begins
to unravel these issues. For example,
Ha¨gerha¨ll et al. (2004) have performed a more
systematic inquiry into the relation between
aesthetic preference and fractals. In the first
stage of the study, 119 participants indicated
which silhouette outlines of 80 nature scenes
they preferred most. In a next stage, the fractal
dimension of all these silhouettes was calculated.
It is worthwhile to note that the photos of
settings with water features and hills were left
out of the total pool of pictures. The reason is
that these elements have a strong influence on
the visual inspection and aesthetic judgment of
landscapes (e.g., Ulrich, 1981), which could
distract participants from concentrating on the
silhouette outlines. For the remaining 52 pictures,
analyses showed a modest but significant
correlation between mean preference and the
fractal dimension of the silhouettes. Although
further research is needed, this finding lends
support to the claim that fractal characteristics
play a significant role in our biophilic responses
toward vegetated/natural landscapes.
Fractal architecture. The previous discussion
tentatively suggests that the beneficial effects
associated with certain natural objects
(positive affect, liking reactions, stressreduction)
could be tapped with fractal characteristics
but without the presence of actual representations
or imitations of nature. Indeed,
fractal structures seem to capture some essential
features of naturalness, such as the recurrence
of (similar) detail on subsequent scales of magnitude.
However, the architecture of many modern
environments is becoming predominantly
euclidean. This trend is orthogonal to our (hypothesized)
predilection for fractal structure,
which could have subtle but definite psychological
and physiological costs. This problematic
320 JOYE
situation can be countered (to a certain extent)
by architectural work that implements some essential
fractal characteristics. Our preference for
a specific fractal dimension further indicates
that the aesthetic effects of such buildings can
be maximized for intermediate levels of complexity.
Perhaps this reflects our preference for
intermediately complex environments, such as
savannas.
If true, the previous findings underscore the
value of integrating fractal characteristics in
architectural design. In essence, fractal architecture
can be realized by repeating similar details
on multiple hierarchical scales of an architectural
design. Despite the growing attention for
fractal aesthetics, which can be witnessed today,
we am not aware of actual instances of fractal
architecture explicitly rooted in the current theoretical
framework. This, however, does not
preclude that, historically, instances of fractal
architecture have been constructed, albeit for other
theoretical or ideological reasons. According to
Michael Ostwald (2001), the first examples of
architecture, referring to fractal theory, began to
appear shortly after Benoit Mandelbrot’s seminal
book Fractals: Form, Chance and Dimension.
Although there has been a rise in fractal architecture
from 1978 to 1988, this trend did not persist
during the 1990s. Yet, in recent years there is a
renewed interest in integrating the complexity sciences
and fractals in architecture. To a certain
extent, this is due to the publication of Carl
Bovill’s Fractals in Architecture and Design
(1996), in which fractal geometry is advanced
as a useful design instrument. With his books
The New Paradigm in Architecture (2002) and
The Architecture of the Jumping Universe
(1995), architectural theorist Charles Jencks has
undoubtedly an important share in bringing the
issue of fractal architecture to the attention of
the architectural community. Nevertheless,
some have argued that Jencks gives a skewed
account of fractal architecture because he essentially
misrepresents what a fractal actually is
(Joye, 2006; Salingaros, 2004). This has led
some to conclude that his use of the notion
fractal in architecture mainly serves rhetorical
purposes (Joye, 2007).
Fractals have been implemented in architecture
in many ways, albeit consciously or intuitively
(for a review, see Joye, 2007). Probably
the most striking examples of fractal architecture
have been intuitively constructed, before
the systematic description of fractal geometry.
For example, Leonard Eaton (1998) argues how
Frank Lloyd Wright (unconsciously) emulated a
fractal-like geometry in his Palmer House. Nevertheless,
it should be noted that the fractality of
this building is predominantly situated in
ground plan, and this approach has been criticized
by Joye (2007). Perhaps more convincing
examples of three-dimensional fractal architecture
can be found in Gothic architecture (Figure
5). In this regard, Goldberger (1996, p. 101)
notes that “fractals capture several key features
of Gothic architecture: its porous ‘holeyness’ or
carved-out appearance, its wrinkled crenelated
surfaces, and its overall self-similarity. . .From
a distance, the sharp spires are the dominant
feature. Closer proximity reveals that these
spires are not smooth, but have spiny outgrowths.
Yet closer inspection reveals even
more pointed detail superimposed on these ornaments.
The repetition of different shapes
(arches, windows, spires) on different scales
yields a combination of complexity and order.”
In agreement with the Gothic, the shape of
certain Hindu temples also has conspicuous
fractal characteristics (Figure 6). The makeup of
these buildings cannot be viewed separately
from the Hindu worldview. In particular, Hindu
cosmology is in a sense holographic in that all
parts of the cosmological whole are the whole
itself and contain all the information about the
whole. Some schools of Hindu thought advance
the (related) view that the macrocosm is encapsulated
in the microcosm: “The entire cosmos
can be visualized to be contained in a microcosmic
capsule, with the help of the concept of
subtle elements called ‘tanmatras.’ The whole
cosmic principle replicates itself again and
again in ever smaller scales. The human being is
said to contain within itself the entire cosmos”
(Trivedi, 1989, pp. 245–246). Both these cosmological
conceptions can be straightforwardly
related to fractal self-similarity, where the
global formal structure recurs, on ever finer
subscales, in the microstructure.
A potential problem for the argument presented
here is that not much architecture displays
the very profound fractality of Hindu or
Gothic architecture, which could cast doubts on
the hypothesized universal preference for fractal-like
patterns. However, some claim that, historically,
architecture has always had an important
fractal component (Salingaros, 2006), in
321ARCHITECTURAL LESSONS FROM ENVIRONMENTAL PSYCHOLOGY
that many buildings display architectural detail
on different scales of magnitude, without having
a more exact sense of self-similarity. Indeed,
a consideration of some of the high points
of Western architecture, ranging from, for example,
the Gothic to Baroque and Organic Architecture,
quickly reveals a remarkable tendency
for a cascade of detail, going from the
largest building structure to the smallest decorative
element. This view is also empirically
supported for divergent building styles (e.g.,
Bovill, 1996; Burkle-Elizondo & Valde´zCepeda,
2006; Capo, 2004; Crompton, 2002).
Still, when observing modern urban settings,
it is also a matter of fact that not all architecture
of all times contains references to natural form,
which suggests that tastes are not exclusively
dictated by biological predispositions. How can
this be reconciled with the hypothesis that we
are in a sense genetically predisposed to affiliate
Figure 5. Gothic architecture often has an important fractal component because it contains
a wealth of architectural elements on increasing smaller scales of magnitude. (Copyright ©
Yannick Joye.)
322 JOYE
with natural forms and to express this affiliation
artistically? An answer is that inborn mechanisms
do not imply genetic determinism but
instead are in a sense open in that they can
interact with cultural or experiential parameters.
Although in this study we mainly focused
on immediate affective responses to nature,
Ulrich’s (1983) psychoevolutionary model also
leaves room for more cultural modes of aesthetic
appreciation, which interact (in a complex
way) with immediate affective responses. Consistent
with this is that discussions on innateness
are sometimes framed in terms of biologically
prepared learning rules, where experiential,
and hence cultural, influences are attributed a
significant role (Cummins & Cummins, 1999;
Ulrich, 1993).
Although it is plausible that changes can occur
in artistic taste, 1
this does not in any sense
invalidate the argument that the outlook of certain
habitats is more attuned to a set of specific
hardwired affiliations, which were discussed
here. Again, it is unproblematic that people hold
specific tastes by which they also become surrounded
by nonnatural architectural forms.
Problems could arise when the artistic expressions
of these (more culturally colored) tastes
gain dominance, with the result that chances for
experiencing natural forms, and the associated
biophilic responses, are significantly reduced.
Of course, prevailing cultural tastes could clash
with basic-level biological tastes, which could
indicate that there is a complex interplay between
the two modes of appreciation. Probably,
architects are sensitive to what is culturally
fashionable and are thus in a good position for
coherently fusing biological and cultural tastes
into a successful architectural expression.
Discussion
In this article, different research disciplines
were drawn together, ranging from environmental
psychology to architecture. This speculative
and interdisciplinary study can, therefore, be
understood as a contribution to the integration
of (subfields of) the scientific and cultural
worlds. The argument began with a survey of
findings from the field of environmental psychology,
which revealed that humans are affectively
related to specific natural elements and
settings, being the result of human evolution in
a natural environment. Today, however, modern
habitats contain increasingly less actual nature
or artistic references to natural form or to the
structural organization of preferred natural settings.
Although such a trend undoubtedly has
1
However, a question that immediately springs to mind
is, who holds these tastes? Is it the general public or is it the
artists themselves? If the artists, then it nevertheless remains
an open question whether these changes in taste are also
appreciated by the broad public, which is the audience for
whom biophilic architecture is intended. In this regard, it
can be noted that there is often a discrepancy between the
aesthetic tastes of laypersons and those of experts (e.g.,
artists). For example, in a playful experiment, Russian artists
Vitaly Komar and Alex Melamid found that people
from different cultures preferred kitschy landscape paintings
over nonrepresentational abstract art (see: www.diacenter.org/km/).
Although it is premature to deduce definite
conclusions from these observations, it nevertheless
shows a more complex view than the adagio that tastes are
essentially variable.
Figure 6. Three-dimensional generation of the central spire of a Hindu temple. One
architectural element is repeated on subsequent scales, which results in a complex aesthetic
object. (Copyright © Yannick Joye.)
323ARCHITECTURAL LESSONS FROM ENVIRONMENTAL PSYCHOLOGY
artistic and epistemological consequences, the
more profound implication is that it can negatively
influence psychological and physiological
functioning. According to the argument of
the current study, biophilic architecture can help
in overcoming the discrepancy between ancestral
and current habitats. More specifically, the
architectural imitation of natural elements and
habitats that promoted fitness (e.g., vegetative
structures) can lead to the autonomous and
quick onset of positive affective reactions,
which can lead to positively toned feelings and
stress reduction. It was argued how such imitations
can be realized according to different levels
of abstraction, ranging from literal imitations
to the application of more abstract geometric
features of natural objects (e.g., fractal
geometry) and structural features of ancestral
habitats. Applying fractal geometry to architecture
could be a particularly successful creative
strategy, because it is not directly restricted by
stylistic conventions and thus does not exclude
the expression of cultural or local tastes.
Nature-based architecture implies that the
building enters into a dialogue with a specific
set of human inborn affiliations. However, adherents
of biophilic architecture should become
aware that their work also has to relate to or
become embedded in a social, historical, ecological,
and individual context (Kellert, 2005).
Indeed, the notions “should” and “has” are at
their place here. It would be contradictory that,
in a social–psychological project like the one
presented here, attention is paid to a basic level
of well-being while other factors that also contribute
to it are totally neglected. The result is
that an exclusive focus on biophilic interventions
is not an automatic guarantee for a higher
level of well-being. For example, it would be
unthinkable for biophilic architecture to be interested
in the short-term or immediate impact
of architecture on well-being, while it remains
apathetic for ecological issues, which are relevant
for the well-being of our future selves and
future generations. Some could claim that this
line of thought weakens our argument for biophilic
architecture. We believe the contrary and
are convinced that a careful consideration of
these factors can maximize the biophilic responses
to architecture, because other interfering
factors are controlled for.
A growing number of academics are involved
in nature-based or biophilic design. In addition
to providing a detailed account of this research
topic, this study hopes to awaken further interest
in biophilic design. This is necessary because
the arguments presented here remain
quite tentative. For example, on a theoretical
level, it would be insightful to come to a finer
grained account of how fractal forms are processed
by the brain. Another more practical
issue is the question of how to create successful
biophilic architecture. It could be true that many
architects have an intuitive feel for the importance
of nature as a source of inspiration. However,
looking at the modern built environment,
it is also a fact that this intuition is not often put
into practice. This report, therefore, tried to
provide some practical guidelines. It should be
noted, however, that it only has scratched the
surface. In a sense, only a few grammatical
rules were presented, and it is up to creative
minds to work out a formal language with these
elemental rules. Such a project can only succeed
by a transdisciplinary approach, in which both
architects and psychologists take knowledge of
this new field of research.
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Accepted July 19, 2007 Ⅲ
Acknowledgment of Ad Hoc Reviewers
The Editor and Editorial Review Board take this opportunity to thank the following
persons who reviewed submissions for volume 11, 2007.
Owen Anderson
John Archer
Paul Bain
Austin Baldwin
William Becker
Mathew Belmonte
Camilla Benbow
Geoff Bird
Simon Boag
George Bonanno
Becky Burch
Natalie Ciarocco
Lee Cronk
Paul Davidson
Valerian Derlega
Yvonne Delevoye
Kathryn Dindia
Carol Dolan
Michael Dougher
Valentina D’Urso
Carol Dweck
Aleksander Ellis
Bruce Ellis
Richard Fleming
Melanie Green
Gary Hardcastle
Christine Harris
William Hirst
George Holden
Harry Hunt
Yuhong Jiang
Peter Judge
Patrik Juslin
Kalman Kaplan
John Kihlstrom
Alan Kazdin
Debra Lieberman
Scott Lilienfeld
Darrin McMahon
Jeanne Marecek
David Milne
Stephen Morillo
Warren Morrill
Shane Lopez
Robert Lynd-Stevenson
David Miall
Susan Mineka
Jeanne Marecek
Irene Pepperberg
Steven Platek
J. T. Ptacek
Devaki Rau
Justin Rentfrow
Matt Rossano
Gad Saad
Catherine Salmon
John Sloboda
Aaron Sloman
David Livingston Smith
Susan Sprecher
Graham Staines
Gary Steiner
Douglas Sturm
Dan Wegner
Michael Wertheimer
Sarah White
328 JOYE