How do you like your light in the morning? : preferences for light settings as a function of time, daylight contribution, alertness and mood

Research has shown that lighting can have an influence on wellbeing, health and performance. In this study, we explore whether lighting preferences reflect these effects. Results of a longitudinal field study by Begemann and colleagues (1997) revealed that on average, office employees’ preferred a higher illuminance than prescribed by current standards for office environments, which are mainly based on ergonomic needs for visual tasks. In addition, they found that the light preferences varied with time of day – roughly following a natural daylight curve. These individual light preferences are said to also depend on a person’s level of alertness and mood, although this has not been investigated yet. In this study, we explored whether time of day, daylight contribution, alertness and mood have an influence on light preference. We hypothesized that people would prefer more intense light when they felt less alert.