Fractal Analysis of Facial Skin Thermogram due to Mental Tasks

We studied changes in fractal nature of facial skin thermogram in experiments conducted by two kinds of mental tasks. One of the tasks was associated with arithmetic and logistic mental activities. Another one was in relation with imagination and thinking activities. Performances using the mental tasks appeared to create different facial thermogram patterns that could be characterized quantitatively in the use of fractal dimensions. In our experiments, there was a lower fractal dimension found during arithmetic task in comparison with rest period before task, showing a smoother facial thermal imagery. Whereas in contrast, the task of thinking induced an increase of fractal dimension of the thermal imagery, leading to a more fluctuated facial thermal surface.