Using stroop task to assess cognitive load

Motivation -- Assessment of cognitive load on user tasks is useful for characterizing user interfaces and tasks with respect to their demands on the user's mental effort. Research approach -- We conducted a controlled experiment with 48 subjects. The primary task involved information search. Stroop-like task was used as a secondary task. Reaction time to the secondary task events was used to assess cognitive load. Findings/Design -- Reaction time on the secondary task differentiated between the primary task stages and the user interfaces. Higher cognitive load component of the secondary task performance discriminated primary task stages, while lower cognitive load component discriminated user interfaces. Research limitations/Implications -- Results presented in this short paper were an unexpected finding. They are thus preliminary and need to be confirmed in further experiments. Originality/Value -- This finding promises a method that separates extraneous cognitive load from intrinsic load. Take away message -- Secondary task can be designed to yield separate assessment of intrinsic and extraneous load.