Physiology and psychology of light and colour: evaluation of an experimental approach

The application of light and colour studies for human well-being is a promising field in design. While good lighting practice is a critical factor in promoting safety and well-being in the workplace, the potential benefits of using light and colour to influence mood and physiology are yet to be fully explored. Since the discovery of ipRGCs and their role in regulating the circadian cycle, new possibilities have been presented to designers to create environments and products that promote well-being, better mood and improved performance. Studying the effects of light and colour on psychology and physiology implies understanding the process of vision and its influence on factors such as circadian regulation and mood. Bridging the gap between psychology and physiology is crucial to harnessing these mechanisms for positive outcomes. This process involves three interconnected brain systems: perception, cognition and emotion. Perception is the fundamental system which extracts hierarchical and increasingly complex information from the neural codes of the stimulus. Cognition integrates this information with prior knowledge to create a meaningful representation of the environment. Emotional evaluation occurs concurrently with cognition and influences preferences and behaviour based on the affective valence of the processed information. Recent studies have shown that humans’ perception of colours is influenced not only by visual factors but also by physiological processes. Although, for example, warm and bright colours such as yellow and red are commonly associated with an “activating” effect, while physiologically activating colours are at the opposite end of the spectrum (blue), how this process occurs at the “perceptual” level is not yet well defined. By exploring the relationship between colour and emotion and its potential effects on physiology, designers can create environments or products suited to specific needs, such as promoting relaxation or increasing concentration and alertness. In this paper, we will describe the process of evaluating various factors and issues in the creation of a practical experiment for the verification of the possible existence of a predictable correlation between physiology and psychology regarding the perception of light and colour from the various psychological biases that can affect the results to the experimental conditions, to obtain results that can be declined in a real lighting design context. The potential applications of light and colour studies in design are vast and diverse. Lighting design can create engaging spaces that promote well-being. In product design, colour and lighting can enhance the functionality of luminaires to improve many physiological aspects and the appeal of areas. Combining physiology and psychology in this field may enable the creation of elements that enhance daily life. As we learn more about these topics, the possibilities for tailored design will continue to grow.