In the modern world, designers and planning authorities are responsible for creating and approving new spaces that contribute to a pleasant, healthy and sustainable environment. As such, policies, standards and procedures for architectural, urban and landscape designers increasingly anticipate the use of approaches which have a positive impact on human perceptions and behaviour (Shaftoe 2008; Gutman 2009). Such expectations have, since the 1970s, been driving an increased practical interest in explaining or predicting human responses to space and form (Perloff 2015). Indeed, theories about the way in which people perceive and respond to the spaces they inhabit can be found in the oldest architectural treatises and the earliest utopian works (Kruft 1994). Not surprisingly then, the concept that a particular combination of space, form and context might have a positive effect on a person’s emotional state is often raised in the design disciplines (Menin 2003; Crankshaw 2008) and it has even found its way into various guidelines and primers (Lidwell et al. 2003; Lippmann 2010).
Probably the most known theory for explaining environmental preference in the architectural, interior and urban design disciplines is ‘prospect-refuge theory’, although its application in design actually combines aspects of Berlyne’s (1951) ‘arousal theory’ and Kaplan and Kaplan’s (1989) ‘information model’ with Appleton (1975) prospect-refuge theory. The merging of these different theories, along with several additional themes, was proposed by Grant Hildebrand (1991), an architectural historian attempting to explain the innate appeal of several of Frank Lloyd Wright’s residences. Hildebrand’s (1991, 1999) research combined several different explanations of human perceptions and emotions to propose a formula for creating an ideal environment.
In the last two decades this expanded variation of prospect-refuge theory has seemingly become accepted in the design disciplines as offering an explanation of basic human responses to the environment, and as a type of guideline for creating ideal spaces (Kellert 2005; Lippmann 2010). However, Hildebrand’s argument is entirely qualitative, as too is Appleton’s, which is also, despite the way it is cited in architecture, about preferences for landscape views. Nevertheless, architectural applications of this theory are allegedly seen in the works of renowned designers including Alvar Aalto and Pritzker prize winners Glenn Murcutt, Jørn Utzon and Peter Zumthor (Gallagher 2007). But once again, the evidence for these claims is qualitative and circumstantial. Indeed, arguments for the efficacy of prospect-refuge theory in design only rarely identify specific quantitative or empirical studies to support their claims. This situation is the catalyst for the present paper, which revisits the key quantitative evidence that is available for prospect-refuge theory (and its associated theories) to collectively assess their findings and relevance to the design of landscapes, cities, buildings and interiors.
Originally, developed by Appleton (1975) for explaining preferences for certain landscapes, prospect-refuge theory argues that we derive feelings of safety and pleasure from inhabiting environments that offer both views and a sense of enclosure. This appeal is arguably universal and subconsciously influences our day-to-day decision-making (Ellard 2009). The central assumptions of prospect-refuge theory can be connected to both Darwinian nineteenth century anthropological beliefs about survival instincts as well as to phenomenological studies that examine environments in relation to the human body (Husserl 1973). Prospect-refuge theory also has parallels with arousal theory, which suggests that an increase of pleasure is felt when a person views a space or scene that has a degree of uncertainty or novelty about it, but if uncertainty is increased beyond that point, feelings of anxiety begin to occur (Berlyne 1951).
In architecture and design, Hildebrand (1991, 1999) expanded the standard definition of prospect-refuge theory to include four additional spatio-cognitive elements: mystery, complexity, enticement and illumination. Most of these can be traced to Kaplan and Kaplan’s (1989) information theory framework which suggests that environments that provide increased opportunities for gathering or discovering information allow for improved living conditions including heightened safety. Thus various spatio-cognitive properties associated with exploration potential (including complexity and mystery) also have an impact on environmental preference.
As a result of the work of Hildebrand (1991), a growing number of architectural critics and historians have used an expanded definition of prospect-refuge theory to justify or analyse architectural spaces in terms of psychological wellbeing (Jacobsen et al. 2002; Roberts 2003; Gallagher 2007; Unwin 2010). The resultant model of a preferred environment has four components. First, a space must have a view or outlook, and second, that view must be at least partially framed or enclosed. Third, a degree of visual complexity enhances feelings of safety and finally, a sense of mystery (implying discoverability or directionality) is preferred (Dosen and Ostwald 2013a).
Despite this apparent agreement between researchers, the capacity to understand and shape human perceptions of environments is actually a more complex and vexed topic. For example, the way people perceive environments is clearly different depending on their physical stature and size or the personal experiences (Wohlwill 1976; Heerwagen 1998). Despite this, architectural and design texts tend to selectively emphasise the universal aspects of spatial experience (Kellert 2005; Lippmann 2010). This may not be entirely unreasonable because people do experience aspects of space, including its organisation, in similar ways (Ellard 2009). For example, quantitative studies have shown that a close visual connection between habitable space and nature is beneficial for psychological wellbeing, recovery and stress relief (Kaplan and Kaplan 1989; Heerwagen and Orians 1993). Studies have also observed that restricted views may cause negative reactions (Heerwagen 2008) while visual connections might encourage movement and evoke pleasure through the exploration of space (Kaplan 1987). There is evidence that people have a preference for spaces which feature access to nature and daylight (Ulrich 1993) and for surroundings that support social interaction and thereby create safer environments (Kuo and Sullivan 2001; Ellard 2015). In addition, a preference for water views, which are perceived as calming, is often noted in studies (Ulrich 1984; Kaplan and Kaplan 1989; Heerwagen and Orians 1993). However, Stamps (2006, 2008a, b) examined ratings for comfort and preference for both natural and built environments and concluded that the statistical significance of prospect, refuge and luminosity factors, in shaping emotional response, was ‘very near zero’ (Stamps 2008b, p 141). Indeed, the only factor which Stamps found had any evidence of shaping environmental preference was ‘venue’, being the particular type of environment where the studies were undertaken. Stamps’ findings emphasise the fact that the evidence for environmental preference theory, and especially as it relates to different types of designed environments—the urban, architectural and interior—is more complex than it seems.
The present paper summarises and classifies the results of thirty-four studies that have used quantitative means (generally data derived from surveys, interviews or computational and mathematical analysis) to examine the veracity of four specific spatio-cognitive factors—prospect, refuge, mystery and complexity—as part of spatial preference theory in design. The first two of these factors are the most commonly tested, as they were the earliest proposed by Appleton (1975), while research into the latter pair is less common, and is often associated with Hildebrand’s (1991, 1999) identification of them as being equally significant in architecture and design. Importantly, this paper does not undertake a detailed review of the methods that have been used to test these factors, as the majority have already been examined from a methodological perspective (Dosen and Ostwald 2013b). Instead, the results of the thirty-four studies are each classified in terms of whether their findings support the efficacy of each of the four factors, or are neutral, or contrary in terms of their role shaping environmental preference.
In addition, to reviewing the results of the thirty-four studies holistically, they are also divided into three groups in accordance with their specific focus or venue of testing. The three groups are: urban studies (9 %), territorial studies (29 %), and architectural studies (62 %). This division by venue or focus is significant as it assists in differentiating which evidence can most reasonably be used to support arguments about interiors, cities and landscapes. Furthermore, while findings associated with the four specific factors—prospect, refuge, mystery and complexity—will be collectively considered in the conclusion, many results are specific to the environment or venue they were tested in. For example, the ratings for prospect and refuge conditions can be heavily influenced by concerns about safety when being exposed in a natural or urban environment, while this is less of a concern when being inside a building. Thus, the results of the various studies analysed here are often valid in a particular context, but not necessarily in any other.