The estimation method for human cognitive state at man-machine interface was investigated by means of psycho^physiological method. The estimation method is firstly to reduce data patterns seen in the short-time responses of multiple physiological measures, and then to construct discriminate functions which correlate the obtained data patterns with the different kinds of cognitive state. The used physiological measures are eye saccade fraction, eye pupil size, eye blinling rate, skin potential response, heart rate and respiration rate.
By using protocol data taken from a subject during a cognitive task experiment, three different kinds of discrimination functions were constructed, based on wither fuzzy logic method or statistical analysis (quantification method class-2). The intercomparison of the three functions thus obtained was made with respect to the limitation of the proposed psycho-physiological method and its applicability to personal differences.