In order to evaluate intellectual productivity such as the efficiency of performing mental works,
several studies have been conducted where the operational logs of mental tasks were evaluated.
However, it is also necessary to analyze Cognitive Load in mental workers so that the productivity can be evaluated accurately.
The authors therefore have proposed a Performance-Cognitive Load model which deals with both task performance and Cognitive Load.
By using the model, they have also developed the inference method of the cognitive working states which can
evaluate intellectual productivity in more detail than conventional methods.
The operational logs of mental tasks as well as pupil diameter and heart rate of the worker were employed as input of this method.
As the result of the subject experiment, the authors found that the feasibility of this method so as to evaluate cognitive working states could be suggested
and this method could well explain the detail changes of their states.
This method is expected to be the novel evaluation method of intellectual productivity.