Psychological and physiological effects of light and colour on space users
Creators: name: Abbas, Nadeen
Publisher: name: RMIT University
Year: 2024

description: The impact of colour and lighting conditions on the emotions and performance of people is gaining greater importance in our urban societies. While large resources are allocated for well designed spaces with the right choices of colour and lighting conditions, there is little scientific evidence that supports these choices. <br><br>Although the literature on light and colour is extensive, it does not present a uniform set of findings for a consistent perspective on the influence of colour and light. Most of the research reported in this field uses subjective measures to study the emotional effects of light and colour on people. It has been reported in literature that emotion manifests itself in three separate sections; (i) physiological (i.e. objective measures), (ii) psychological (subjective measures), (iii) behavioral, and it is necessary that studies not be limited to the assessment of a single response but include sample measures from each of the three manifestations. <br><br>This research is built on the current body of knowledge that there is a need for a study on the emotional effects of light and colour on people using physiological and psychological measures, to ensure the objectivity and reproductivity of the experiments. <br><br>It is well documented in literature that there is close correlation between emotions, heart rate (HR), and skin conductance (SC). Hence HR and SC are expected to be good physiological measures of environmental conditions on people. Thus this thesis reports changes in the HR, SC and self-assessment reports of arousal and valence (SAM) for people when exposed to different colour and intensity lights. The aim is to help provide an objective rationale for the choice for light intensity and colour by architects, interior designers and other professionals. <br><br>The experiments were conducted on 15 participants who were exposed to 8 different colour and intensity light conditions. The participants' HR and SC were recorded under each colour and intensity light, and they were asked to complete SAM. The research demonstrates that there is a change in HR, SC, arousal and valence of participants due to change in the colour and intensity of lights. However, the direction of change was subject dependent, where the same colour and intensity light can have different effects on people. <br><br>The research suggests that architects and designers of any space must take into account the individual differences of the predicted users when designing the lights and colours. <br><br>It is also seen from the results that some colour and intensity lights have greater impact on the emotions of participants than others. Although it is not possible to correlate the colour and lighting conditions to a specific effect on all participants, general effects for some colour lights were drawn from the results. <br><br>It is well documented in literature that HR and SC are a good measure of emotion. However the results of this study show very high inter subject variation in HR and SC. This is due to people having different HR and SC in normal conditions. This research demonstrates that the use of HR and SC to measure the effect of a stimulus on a group of people is unreliable because it is hard to compare the results.