Summary.-Previous experiments using the method of psychophysical scaling on public preferences for residential styles indicated that residences designed to ...
Perceptual and MotorSkills, 1993, 77, 99-103. O Perceptual and Motor Skills 1993
PUBLIC PREFERENCES FOR RESIDENCES: PRECODE, CODE MINIMUM, AND AVANT-GARDE ARCHITECTURAL STYLES ' ARTHUR E. STAMPS 111 Institute of Environmental Quality Summary.-Previous experiments using the method of psychophysical scaling on public preferences for residential styles indicated that residences designed to meet the planning code were judged to be less pleasant than the average pleasantness of a random sample of the city's residences and just as pleasant as architectural avant-garde projects. However, the size of the stimulus sample in that previous experiment was too small to detect concrasts among precode, code minimum, and avant-garde projects. In this experiment the size of the scimulus sample was increased. Scatistically significant contrasts were found, indicating that the avant-garde residences were judged to be more pleasant than the planning code minimum and the precode residences.
This study compared public preferences for three architectural styles, residences constructed before a planning code required urban design considerations (Precede), residences constructed to conform to the minimum planning code requirements (Code minimum), and residences constructed as nonconforming avant-garde architectural statements (Avant-garde). There are several reasons why this research is needed. First, as many as 90% of the cities in the United States have some form of architectural appearance controls, yet there is very little scientific research on how effective those controls might be (Stamps, in submission). Second, previous research indicated that preferences obtained with preconstruction psychophysical experiments correlated .73 with as-built public preferences while preferences obtained with a preconstruction design jury correlated only .I0 with as-built preferences (Stamps, 1992b). This finding suggests that, if architectural controls are to be validated, validation is best done scientifically. Third, the previous research on residential architectural styles indicated that residences built to conform to a local planning code were judged to be less pleasant than the average judged pleasantness of a random sample of the city's residences (Stamps & Miller, 1993), suggesting that the planning code might have been counter-productive. However, it could also be the case that comparing code-minimum residences to a random sample of residences is too strict a test and that a fairer criterion on which to evaluate the efficacy of an urban design control would be to compare code-conforming residences to what would have been built without the code. In the city under investigation there were two residential styles which met this criterion, residences built just prior to the code and 'Address requests for reprints to A . E. Stamps 111, Institute of Environmental Quahty, 290 Rutledge Street, San Francisco, California 94110.
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noncomplying avant-garde architectural residences. Each of these styles has a major constituency. Planners have an interest in knowing whether the code at least raised the judged pleasantness of residences over what was being built just before the code, and architects have an interest in knowing how the local public would respond to the full expression of the architects' artistic freedom. The previous experiment contained some examples of precode and avant-garde residences, but a power analysis of that experiment indicated that the size of the stimulus sample was not adequate to detect differences among code-conforming, precode, and avant-garde residences. Accordingly, this study augments the previous work by increasing the sizes of stimulus samples for residences built before the planning code went into effect and for avant-garde architectural residences. Based on the previous results, it was hypothesized that the planning code-conforming residences would be judged more pleasant than the plain, boxy residences built just prior to implementation of the code. Previous results regarding local public preferences for avant-garde designs were not definitive. O n one hand, a pair of studies of high-rise buildings indicated that the local public would judge avant-garde designs more pleasant than "safe" designs (Stamps, 1991a, 1991b). O n the other hand, previous work on residential preferences indicated that older residences would be judged more pleasant than newer residences (Stamps & Miller, 1993). Accordingly no a priori hypothesis was attempted regarding the contrast between the avantgarde residences and the other two styles.
Respondents Respondents were selected by a professional survey research firm using random protocols described by Stamps and Miller (1993). For this experiment there were 43 respondents. The age range was 1 8 to 63 years. The median age was 31. There were 2 1 males and 22 females. Data on socioeconomic status were not obtained, but data on household income were. Eight respondents reported annual household income from $0-10K, two reported income from $10-20K, 15 reported $20-30K, 7 reported $30-50K, and 11 reported incomes greater than $50K. There were 13 Caucasian, 6 Hispanic, 11 Asian, 11 black, and 2 other races. For readers interested in comparing this ethnic distribution with the proportionality of racial representation in the community the 1990 U.S. Census data for this area were white non-Hispanic 46%, Hispanic 14%, Asian 29%, black 1I % , other a fraction of 1%. Stimuli The stimuli consisted of 24 residences located in an American city. All stimuli were located in low density (one or two unit) residential zones. There were three styles of stimuli, plain, boxy residences built just before the plan-
PREFERENCES FOR RESIDENTIAL DESIGN
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ning code took effect, residences designed to conform to the planning code, and avant-garde residences. The stylistic components of the precede and code-minimum styles were identified from a previous random sample of the city's residences. Readers interested in inspecting photographs of that sample of residences will find the photographs in Stamps and Miller (1993). The main precode design features were (a) two to three stories, (b) flat roof, (c) flat facade, and (d) horizontal trim. The main design features for the codeminimum buildings were (a) two to three stories, (b) flat roof, and (c) bay windows. The avant-garde residences were selected from a list of innovative new residential designs provided by the local chapter of the American Institute of Architects. Aside from being two or three stories, these residences defied description. Fig. 1 shows typical examples for each style. Eight residences of each style were used in this experiment.
R-1 Zoning
R-2 Zoning
Precode
AvanteGarde
FIG. 1. Examples of stimulus samples. Residences shown on the left contained one dwelling unit (R-1 zoning). Residences shown on the right contained two dwelling units (R-2)zoning.
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Task Respondents viewed a slide of each residence and rated it on a scale of pleasant/unpleasant. The ratings were scored from 1 to 8, so lower scores indicated greater reference.
Sample Sizes The minimum respondent sample size (nr30) was based on split-block replication studies described by Stamps (1992a). To protect the experiment against nonparticipation, an experiment with 45 respondents was planned. The size of the stimulus sample was based on power analysis for repeated measures (Cohen & Cohen, 1983), using a = .05, power = .80, mean contrast = .24, and population standard deviation = 1.17. The estimates of mean contrast and population standard deviation were obtained from the data described by Stamps and Miller (1993). Using the equations given by Cohen and Cohen (1983, Chapter 8) and assuming there would be one degree of freedom for each style contrast, approximately 350 observations would be needed for each style (Cohen, 1988, p. 312). Since in repeated measures, the number of observations is approximately the product of the number of respondents and the number of s t i m d , and since 45 respondents were anticipated, 8 stimuli would be needed for each style.
RESULTSAND DISCUSSION The data were analyzed using repeated-measures analysis of variance and contrasts among the three styles of precode, code minimum, and avant-garde. Descriptions of the analysis are given by Winer, et al. (1991, p. 228-233). Table 1 shows the analysis of variance; the stimulus effect is clearly significant. Mean values for the three styles were Avant-Garde 4.04, Code Minimum 4.56, and Precode 4.95. Since lower scores indicated greater preference, the avant-garde projects received the highest ratings. Table 2 shows the mean contrasts among the styles. F ratios were obtained by calculating sums of squares for each contrast and dividing each sum of squares by the residual mean square of 1.96. Details on this calculation are given in Winer, et al. (1991, pp. 228 ff). Afl pair-wise contrasts were statistically significant. The data clearly support the hypothesis that residences which conform to the planning code requirements were preferred over the plain, boxy resiTABLE 1
ANALYSISOF VARIANCEOF PREFERENCES Source
SS
d/
MS
Respondents Stimuli Residual Total
68 1
42
16.2
327
23
14.2
1898 2906
966 103 1
1.96
F
P
7.2
< ,001
103
PREFERENCES FOR RESIDENTIAL DESIGN TABLE 2
MEANCONTRASTS BETWEEN STYLES Contrast Avant-garde-code minimum Code minimum-precode Avant-garde-precode
Ur-U?
FI 966
P
-.52 -.39 -.91
21 14 72
