Perception of colour stimuli is found to trigger corresponding emotional and behavioural responses within human beings. Literature establishes that red is stimulating while blue is pacifying. There seems to be divided theories on how these associations are being generated. It is argued widely that colour associated emotional responses are learnt and subjective while another theory is that it is a general innate response. A third theory discusses about a combination of both learnt and innate responses. The present paper reviews literature on the above three suppositions and enlightens on a study done seeking innate, general emotional reactions triggered by colour stimuli. A questionnaire survey was conducted using guided imagination technique with a group of volunteer undergraduate students (n=86). The participants were guided to imagine five emotional/behavioural states spontaneously and recognize the corresponding colour/colours. The findings to a greater extent support the general emotional responses triggered by colour stimuli. Red and orange (79%) was dominating in their imaginations as appetizing and blue as least appetizing (60%). None (0%) imagined red as a calming colour and blue (2%) as a violent colour. The study also revealed certain learnt emotional responses. For instance, white (51%) was found to be calming, suspect to be a religiously and socially learnt emotion.

Individuals with physical disabilities, especially with impeded mobility have to deal with an array of physical, social, cultural and economic challenges, consequently leading to psychological imbalances, disorders and more inclined to attempt even suicide. Incorporating disabled-friendly design interventions, facilitating optimal healing in their healthcare facilities, is crucial to overcome most of these challenges and ensure their psychological well-being. Within this backdrop, this investigation focused on the impact of interior colours in health care facilities to manage depression, anxiety, and stress levels of disabled individuals. The investigation was executed with reference to wall colour of bedrooms of patients with limb deformities of a selected rehabilitation centre, at Ragama. Three hues (blue, yellow, and green) were tested by installing colour panels on the sidewall of the beds, allowing the patients to be exposed to each colour for three consecutive days. DASS-21 self-report scale was adopted to measure depression, anxiety, and stress levels of the patient. Green colour was found to be significantly supportive in inducing favourable impacts to manage depression, anxiety, and stress levels of patients over blue and yellow. Extending this study to test different tints, shades, and intensities of green colour, incorporating large samples with long-term exposure in an array of health care facilities, is recommended.

Theory of colour -a long-established tradition of artists -differentiates between the impacts of warm and cool colours respectfully on human beings. The lack of scientific and statistically substantiated knowledge on aforesaid colour associated thermal perception (CTP) deems to hinder its optimum integration in creating responsive built environments. This investigation seeks scientific explanation on manifestation and contributing factors of CTP with reference to a warm colour (red-RTP) and a cool colour (blue-BTP). The hypothesised potentials of CTP to manifest as a psychological response, a biological response, a factor altering core body temperature or as an actual thermal sensation caused via the human skin (due to heat radiation emitted by coloured surfaces) were tested. A crossover experiment was executed with a sample of healthy male undergraduates (n=111) selected via stratified simple random sampling (age 19 -30), under controlled laboratory conditions. Substantiating colour theory, subjects demonstrated a propensity to perceive red as warm/hot (64.2%) and blue as cool/cold (59.3%). As revealed by logistic regression, CTP neither manifests due to a fluctuation in core body temperature nor as an actual thermal sensation. It is a psychological response characterised by common as well as colour-specific factors. Accordingly, thermal impacts of colour could be integrated in indoor environments to psychologically manipulate the perceived thermal environment against the real thermal condition to achieve the desirable thermal milieu. This novel knowledge may provide insights for Architects, interior designers, relevant authorities and organisations to develop strategies incorporating thermal impacts of colour to achieve low-energy design.Colour is an expressive agent according to Rihlama (1999), which can convey ideas, concepts, signs, symbols, meanings and messages associated with the intended

Depression, anxiety, and stress symptoms are alarmingly increasing among university student populations and may have a major impact on achieving their academic and life goals. It is seen that in most cases the student's academic performance, health, and quality of life is negatively impacted as a result. Research suggests that Architectural elements have an impact on mental distresses and individual wellbeing. This research attempted to address the above concern by focusing on the impact of colour, as an Architectural element, on psychiatric imbalances among Undergraduates with special consideration on depression, anxiety, and stress levels. The study was conducted with 36 participants from the Department of Architecture of the University of Moratuwa. Due to the COVID-19 pandemic's travel limitations, the study was conducted remotely through Zoom online conferencing platform and non-immersive virtual mode under three selected colour conditions (tints of green, blue, and red) with the aid of DASS-21 scale to evaluate stress, anxiety, and depression levels. Colour red was found to induce the most adverse impacts on stress, anxiety, and depression levels, whereas green indicated a comparatively low adverse impact. Blue had the slightest adverse impact on depression and anxiety with a slightly favourable impact on reducing stress. The findings of this study suggests that the incorporation of appropriate colours in design interventions could facilitate the creation of better classroom interiors in order to address depression, anxiety and stress related disorders of undergraduates. Further investigations in physical mode, incorporating a larger sample and other subject streams is recommended.

The potential of incorporating theoretically-established cool colours within the interiors of a hot humid tropical climate -as an alternative strategy for energy conservationwas tested by this preliminary field investigation with reference to a garment factory in Panadura, Sri Lanka; ventilated using ceiling fans to achieve thermal comfort. It was hypothetically assumed that cool colours can psychologically induce a relatively cool thermal perception than the real thermal condition within inhabitants, leading to a reduction of the operational speed of ceiling fans, and thereby resulting in a reduction of cooling costs. The research examined the impacts of neutral (white), warm (red) and cool (blue) colours on the indoor thermal perception of factory workers by changing the colour of the internal walls of a selected work space by the use of coloured fabric. Fan speed in five progressive levels (L1-L5), corresponding to elevating levels of power consumption, was manipulated within 10 minute intervals until the subjects reached the thermally comfortable level. The study revealed a correlation between the interior colour and the preferred fan speed. 63.63% of workers were found to achieve their perceived thermal comfort with the maximum fan speed L5 in the controled white space while, 31.81 % and 4.5 % preferred L3 and L4 respectively. A majority of the workers (86.36 %) achieved comfort with L5 when exposed to colour red, demanding high energy consumption, while 13.63 % preferred a moderate speed (L3). When exposed to blue, 63.63 % were satisfied with L5, while 9%, 13.63% and 13.63% perceived thermal comfort in L4, L3 and L2 respectively. Blue was revealed to be the most supportive colour in achieving perceived thermal comfort at a comparatively lesser level of energy consumption. Incorporating colour blue in interiors was found to be favorable and red non-favorable for energy conservation in a hot humid tropical climate.