Wood also has psychological effects. In interiors, wood seems to have the power to regulate people’s levels of stress. In a comparison of different work rooms, stress level, measured as the skin’s capacity to conduct electricity, was lowest in a room with wooden furniture. Not even plants brought into a room fitted out in white had the same effect.
The favourable psychological effects of wood have also been proven in schools. In classrooms with whole-wood interiors, the morning stress peak, measured as a variation in pulse rate, subsided soon after arriving at school and did not rise again. In a normal control classroom, a mild level of stress in pupils continued throughout the day. Their experiences of stress, such as fatigue and feelings of inefficiency, were less in wooden classrooms than in normal ones.
The use of wood in interiors also seems to extend to human behaviour and social observation. In offices where wooden products were used, visitors' first impression of the workers was more favourable than in places where there was no wood. In wooden offices, workers seemed better at their jobs, more successful, more honest, more responsible and more reliable than in normal offices. An interesting and unexpected observation concerned the supported living of the elderly. When, in homes for the elderly, wooden materials like wooden trays in the dining room were introduced, in the opinion of the staff interaction between the residents and awareness of their surroundings increased.
It seems that the positive effects of wood cannot be reproduced with imitation wood. Physiological measurements have shown that the quality of sleep and recovery from stress are better in a room with wood than one with imitation wood.a.