A method of quantitatively assessing the effectiveness of an audiovisual, visualor audio advertisement including the steps of: presenting the advertisementto a plurality of subjects, the advertisement having a sequence of audiovisual,visual and/or audio features which occur as a function of time； obtaining, duringpresentation of the advertisement, EEG signals from the subjects from predeterminedscalp sites thereof； calculating SSVEP amplitudes and/or phase differencesfrom EEG signals obtained from the predetermined scalp sites in order to obtainoutput signals which represent predetermined psychological states of eachsubject to the features as a function of time； combining the output signals fromthe subjects to obtain pooled output signals； and displaying the pooled outputsignals to thereby enable quantitative assessment of the subjects' responsesto the features of the advertisement in order to assess the effectiveness of thefeatures of the advertisement.
