Measuring perceived ceiling height in a visual comparison task

ABSTRACT

When judging interior space, a dark ceiling is judged to be lower than a light ceiling. The method of metric judgments (e.g., on a centimetre scale) that has typically been used in such tasks may reflect a genuine perceptual effect or it may reflect a cognitively mediated impression. We employed a height-matching method in which perceived ceiling height had to be matched with an adjustable pillar, thus obtaining psychometric functions that allowed for an estimation of the point of subjective equality (PSE) and the difference limen (DL). The height-matching method developed in this paper allows for a direct visual match and does not require metric judgment. It has the added advantage of providing superior precision. Experiment 1 used ceiling heights between 2.90 m and 3.00 m. The PSE proved sensitive to slight changes in perceived ceiling height. The DL was about 3% of the physical ceiling height. Experiment 2 found similar results for lower (2.30 m to 2.50 m) and higher (3.30 m to 3.50 m) ceilings. In Experiment 3, we additionally varied ceiling lightness (light grey vs. dark grey). The height matches showed that the light ceiling appeared significantly higher than the darker ceiling. We therefore attribute the influence of ceiling lightness on perceived ceiling height to a direct perceptual rather than a cognitive effect.

KEYWORDS:

• Psychophysics
• Perceived size
• Visual perception
• Interior space
• Ceiling height
• Distance
• Virtual reality
• Interior design
• Architecture
• Architectural psychology

Notes

¹Random-effects models assume regression parameters (i.e., the slope) to vary from subject to subject and model the correlation structure by treating the subjects as a random sample from a population of all such subjects. The variance–covariance matrix was specified as being of type “unstructured” (UN). The degrees of freedom were computed according to the approach by Kenward and Roger (1997).