We conducted an experiment to explore the relation between facial temperature and mental effort. Participants had to perform mentally demanding tasks while their face was captured with an infrared camera. The temperature of the nose decreased during these tasks and increased during the successive rest periods. Other parts of the face did not change due to mental effort. The advantage of this workload measure is that it can provide objective and real-time information about mental effort of operators without attaching sensors to an operator. This measure can be used to measure the workload of operators in relatively stable environmental conditions such as air traffic controllers and operators of unmanned aerial vehicles.
Veltman, H. J.,
& Vos, W. W.
(2005). Facial Temperature as a Measure of Mental Workload. 2005 International Symposium on Aviation Psychology, 777-781.