Light and emotion: exploring human affect in lighting

This thesis starts by questioning the efficiency of the current basis of lighting design practice on modern workspaces. The study argues the importance of shifting the basis of guidance from the types of spaces, and activities into human psychological states in the Introduction. Both visual perceptions of the space and human emotion states are theoretically examined as a potential basis for lighting design practice. As a result, the human emotion state, ‘affect’, from the concept of the circumplex model of affect has been chosen as a better exploratory tool. Human ‘affect’ states of ‘lively’ and ‘relaxing’ were hypothesized mental states that people could benefit from in the workspace. A detailed field study, which consisted of two separate phases, was carried out to test the hypothesis. In the first phase of the field study, a group of lighting designers was invited to devise a set of lighting design concepts that explore activation and pleasantness in the circumplex model of affect with the use of smart control of lighting. Then, the thesis investigated the design elements of the lighting settings as well as their photometric and colorimetric characteristics. The result indicated that although the design elements showed particular groupings, such characteristics were not effectively expressed using the current photometric and colorimetric variables. In the second phase of the field study, 15 lighting settings in a controlled interior environment were set up based on the results of the first phase. A group of participants were invited to assess the settings by rating of their visual perceptions of the space and their emotion state. The results indicated that the settings inspired by the designers effectively affect human emotion states while providing high quality visual perceptions of the space. However, the two dimensions of human emotion, activation and pleasantness, did not provide, in detail, a statement of human emotion. Therefore, the thesis has proposed a new indicator that involved four different zones, defined by the two dimensions as an effective tool of measuring human emotional experiences from lighting. In conclusion, the thesis successfully explores the possibilities of an emotion-based lighting design approach and explains their impacts by the field experiment as well as developing and investigating the effectiveness of a new indicator of human affect. The work described in this thesis would work as a fundamental but crucial step to promote human well-being in workspaces by fulfilling various human needs and the potentials of smart lighting technologies