Abstract
Theoretical and practical concerns guided the design of an experiment on how ventilation noise (38 and 58
dBA), air temperature (21 and 278C), and illuminance (300 and 1500 lx) combine or interact in their e¡ects on
cognitive performance. Self-reports of a¡ective states were taken with an a¡ect circumplex measure (Larsen
& Diener, 1992; Knez & Hygge, in press) to study the mediation from the environmental variables over a¡ect
to cognitive performance.
Arousal models (e.g., Broadbent, 1971) would predict that increased levels of noise and illuminance increase
activation and/or a¡ectlevels and that mild heat decreases it. The inverted U-hypothesis would further pre-
dict that intermediate levels of perceived arousal improve attention, memory and problem solving perfor-
mance. A distinction was made between synergetic and antagonistic interactions in order to di¡erentiate
arousal and nonarousal mediated e¡ects on cognitive performance.
The results showed that attention worked faster in noise but at the cost of lesser accuracy, which supports
the Speed-Accuracy-Trade-O¡ hypothesis (Hockey, 1984). Interactions were found between noise and heat on
the long-term recall of a text, and between noise and light on the free recall of emotionally toned words. These
e¡ects on cognitive performance could not be explained as mediated by the a¡ective states, and were not
consistent with an arousal model and the inverted-U hypothesis.
a space with a particular landmark. It should be noted that memorability of colour is limited to only first and
second landmarks or prominent colours seen, so it is best to make only one or two colours dominant for wayfinding
purposes. Lastly, it is important to always remember that colour is all about materials, as all materials come with a
particular colour choice.