S T U D I E S I N V I S U A L PERCEPTION OF ARCHITECTURAL SPACES A N D ROOMS

V . Aesthetic preferences

TOMMY GARLING

Psychological Laboratories, University of Stockholm, Sweden

GARLING, T. Studies in visual perception of architectural spaces and rooms. V. Aesthetic preferences. Scand. J. Psychol., 1972. I3, zzz-z27.-Depicted urban spaces were rated by 24 subjects with respect to pleasantness. The results for colour photographs, ‘detailed’ and ‘undetailed’ perspective drawings were compared. As a common basis for aesthetic preferences, the factors ‘variation’, ‘umbrageousness’ and ‘openness’ were suggested. These factors accounted for 69 % of the variance in multiple linear regression.

In previous papers (Garling, 19690, 19694 19700, I970b), I have discussed the visual perception of architectural and urban space. The point of departure for these studies was the phenomenological descriptions published by students of architecture (e.g., Hesselgren, 1967). The present study will pursue the same approach into the realm of aesthetic evalua- tion.

The aesthetics of architecture has been discussed most thoroughly by Hesselgren (1967), who pointed out several important things worth studying. It was, however, felt that some- what less elaborate views would do in the present context. Consequently, the aesthetic evaluation is here conceived of as a general evaluation or preference, for this was considered the more typical mode of response as far as untrained subjects are concerned, Nevertheless, there may still be substantial communality between subjects’ aesthetic preferences which are connected to the component parts of the experience, i.e. the ‘pure’ perception of form, colour and space as well as more or less complex meanings. The main experimental problem is to isolate these factors in order to find a common basis for aesthetic preferences. In this respect, the problem is similar to those of factor analytic studies in experimental aesthetics (see Wedin, 1969, for a review).

The experiment to be reported represents in the first place an attempt to find a basis for aesthetic preferences of urban space, and, if possible, to define criteria for the design of urban space as aesthetically pleasing. Actually, some suggestions have been offered by Garling (1969~2, 1969b) but since these may be insufficient, data will be collected open- ended by having subjects to rate depicted urban spaces, and, also, by interviewing the subjects.

Secondly, the effects of methods of representation on aesthetic preferences will be investigated in much the same way as has been done previously for depth and size judg- ments (Garling, 1970b), i.e. colour photographs will be compared with perspective drawings. Of course, methods of representation are not design factors but nevertheless important to study because of their value to research and in practice (cf. Garling, 1969~2, 1969b). The experimental design makes possible a direct comparison of the methods, thereby providing

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a basis for evaluating each one. It would, however, also be of considerable interest to study which factors constitute the critical differences between the different methods. The latter problem is related to the problem discussed above, i.e. to find a common basis for aesthetic preferences, and will be approached in an identical way.

T o sum up, the present experiment aimed at (i) investigating the effect of methods of representation (colour photographs and perspective drawings) on aesthetic preferences for urban space, and (ii), in an explorative way, trying to define factors which make urban space aesthetically pleasing or unpleasing.

METHOD

Stimulus material The stimulus material was 3 sets of pictures which have been described in Garling (197ob) .

Briefly, the sets consisted of (i) colour photographs of streets in a small town, (ii) detailed drawings (perspective drawings made from the photographs with all details included), and (iii) undetailed drawings (perspective drawings made from the photographs with only few details included). There were in each set 10 pictures since Nos. 5 and 7 had been omitted as compared with the previous study referred to.

Procedure In a light-proof room, 25 mm slides were projected on a white wall and viewed individually

by the subjects at a perpendicular distance of about IZO cm. The projected sizes of the pictures subtended visual angles of about 60” in width and about 40“ in height. Unrestricted binocular viewing was used.

The subjects were asked to rate each depicted space with respect to pleasantness-unpleasant- ness (trivsamt-otrivsamt). The ratings were made twice of each stimulus presented according to individual randomized orders within sets. The stimulus sets were presented in all possible permutations across subjects. Before the rating session, each set had been shown once.

The rating method consisted of a 7 point rating scale with steps defined numerically and verbally as follows: -3 ‘very unpleasant’, -2 ‘unpleasant’, --I ‘slightly unpleasant’, o ‘neither pleasant nor unpleasant’, I ‘slightly pleasant’, 2 ‘pleasant’, 3 ‘very pleasant’. The instructions which were available in typescript, stated clearly that the subjects were to rate the actual spaces from the pictures though their impressions might vary owing to method of representation. The subjects were allowed as much time as they wished for the ratings. In general, half an hour was enough for the rating session.

After having completed the ratings, the subjects were asked to write down on sheets of paper all relevant attributes of the actual spaces and/or the pictures which they would consider to cause the former appear pleasant or unpleasant. The task was performed without having the subjects see the pictures once more.

Subjects

males and 14 females. The subjects were 24 students of psychology between 18 and 25 years old. There were 10

RESULTS AND DISCUSSION

The ratings were averaged over subjects as arithmetic means. Fig. I shows for each method of representation mean ratings plotted against stimulus number (a monotone ascend- ing function of space-size in units of area, cf. Garling, 197ob). T h e effects of stimuli, methods

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and the interaction stimuli x methods were all significant for p <O.OOI as tested by analysis of variance (McNemar, 1962).

The interrater reliability was computed through the intraclass correlation with between subjects variance removed (Guilford, 1954). For the pooled ratings from one of the subject: a value of 0.51 was obtained, and for the pooled ratings from all 24 subjects 0.96.

A D e t a i l e d drawings

S t i m u l u s number

FIG. I . Mean ratings 'of pleasantness plotted against stimulus number (a monotone ascending func- tion of space-size in units of area) for each method of representation.

The evaluation of the methods of representation The effects of the method of representation will be considered first. Of course, it is not

possible to draw any conclusions about effects of representation per se, since the actual spaces were not rated. I t may, however, be reasonable to assume that ratings in situ would give about the same results as ratings from colour photographs (cf. Garling, 1969b, 1970b). Therefore, the colour photographs will be taken as a criterion in relation to which the other methods could be evaluated, i.e. the two kinds of perspective drawings employed.

As can be seen in Fig. I, the spaces are on the whole rated as less pleasant from the un- detailed drawings than from the colour photographs, whereas the ratings from the detailed drawings are in close agreement with the ratings from the colour photographs. The signi- ficant effects of methods and interaction stimuli x methods are then attributed to the un- detailed drawings. I t is concluded that, in general, perspective drawings may be a useful method of representation (at least as useful as colour photographs). However, unless all details are included there may be distortions, possibly depending on which details are omitted. It is, e.g., conceivable that the undetailed drawings would have been rated as more pleasant had other details been omitted. In order to make these points clear, the following possibilities can be mentioned:

I. The actual spaces could not be rated from the undetailed drawings since these were

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too impoverished and unrealistic. Actually, a few subjects made comments to this effect but most subjects did not.

2. There is a common basis for the aesthetic preferences in relation to which the differ- ence between the undetailed drawings and the colour photographs can be described.

The second point will be assumed to hold true. Consequently, the ratings of all stimuli with disregard to method of representation will be considered in the following discussion.

The basis for aesthetic preferences In order to account for the results with respect to the common basis for aesthetic pre-

ferences, the interview records were consulted. From these records a number of attributes or factors were isolated. However, only the following three factors may be considered since, in contrast to other factors, these were mentioned by nearly all subjects (as preferred or not preferred):

I . Variation. The factor refers to variation in shapes, sizes and colours, irregularities and richness of detail. It was considered by most subjects to be preferred in contrast to its opposites. By inspecting the pictures, it was evident that this factor alone may account for the variance between stimuli and methods. Furthermore, the interaction stimuli x methods may be accounted for, too. Some photographs (e.g., Nos. I , 2 and 12) depicted rather

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FIG. 2. Empirical values (mean ratings of pleasantness) plotted against predicted values according to multiple linear regression. (For further explanations, see text.)

impoverished views, so, as opposed to other stimuli (e.g., Nos. 4-9), a reduction of details would probably not have made much difference.

2. Umbrageousness. This factor was preferred by all subjects. It may account for some of the variance between stimuli but hardly more since the drawings were very similar to the photographs in this respect.

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3 . Openness. The factor refers to the spacing of buildings, the sizes of spaces and the lightness. Opinions differed among the subjects as to whether it was preferred or not.

In order to validate the conclusions drawn above, the following procedure was adopted. Firstly, another z subjects rated the pictures on a 7 point rating scale with respect to degree of variation, umbrageousness and openness, respectively. (The reliability of the pooled ratings was 0.87, 0.98 and 0.96 corrected by the Spearman-Brown formula.) Secondly, the following multiple linear regression equation was fitted to standard scores by the method of least-squares:

z1 = 0.66~~ + 0.412, - 0.0624, where x1 denotes pooled ratings of pleasantness, z2 pooled ratings of variation, z3 pooled ratings of umbrageousness, and x, pooled ratings of openness. In Fig. 2, empirical values are plotted against predicted values. The function accounts for 69% of the variance. It is seen that variation and umbrageousness contribute sizeable amounts to the variance (46 % and 21 %, respectively), whereas openness contributes practically nothing ( z yo). However, by inspection the residuals, it was found that a parabolic type of function might hold between ratings of pleasantness and openness. A curvilinear regression should therefore account for more variance than the linear function fitted to data.

CONCLUSIONS

In summary, it is concluded that variation and umbrageousness are factors of importance for aesthetic preferences of urban space, i.e. constitute a basis for aesthetic preferences. Of course, further experiments with control over the variables are needed. The problem of an objective definition of the factor ‘variation’ may possibly be approached by way of measures of variation commonly used in statistics. Further, there is partial support that openness is of relevance. This result deserves attention since it agrees with the hypothesis offered previously (Garling, 1969a, 19696). Finally, the results substantiate the fact, already pointed out, that the critical difference between the colour photographs and the undetailed drawings is due to the variation factor. The undetailed drawings make the spaces appear less varied, more homogenous, than both the colour photographs and the detailed drawings though to varying degrees for different spaces.

This study was performed under the direction of Professor Sven Hesselgren, Royal Institute of Technology, Stockholm, Sweden, and supported financially by grants from the Swedish National Council for Building Research. The author is indebted to Dr Gunnar Goude, Psychological Laboratories, University of Stockholm, Sweden, for comments on the manu- script, and to Miss Tiuu Purre for assistance.

R E F E R E N C E S

GARLING, T. (1969~). Studies in visual percep- tion of architectural spaces and rooms. 11. tion of architectural spaces and rooms. I. Judgments of open and closed space by Judgment scales of open and closed space. category rating and magnitude estimation. Scand. J . Psychol., 10, 250-256.

GARLING, T. (1970~). Studies in visual perception Scand. J . Psychol., 10, 257-268.

GARLING, T. (19696). Studies in visual percep-

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of architectural spaces and rooms. 111. A relation between judged depth and size of space. Scand. J. Psychol., 11, 124-131.

GARLING, T. (197ob). Studies in visual perception of architectural spaces and rooms. IV. The relation of judged depth to judged size of space under different viewing conditions. Scand. J . Psychol., II, 133-145.

T. Garling Psychological Laboratories University of Stockholm Box 6706 S-I 1 3 85 Stockholm Sweden

GUILFORD, J. P. (1954). Psychometric methods. New York McGraw-Hill.

HESSELGREN, S. (1967). The language of archi- tecture. Lund: Studentlitteratur.

MCNEMAR, Q. (I 962). Psychological statistics. New York: Wiley.

WEDIN, L. (1969). Dimension analysis of emo- tional expressions in music. Swedish J. Musicology, 51, I 19-140.

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