A method of determining the physiological reactivity of an individual with respect to images, comprising: measuring at least one physiological parameter of an individual during a baseline calm period of time; measuring the said at least one physiological parameter of said individual during a stress period of time and a succeeding rest period of time; dividing said measured data for each of said periods of time into a plurality of predetermined time segments; computing a histogram or Fourier analysis as appropriate on said predetermined time segments for each said period of time; standardizing said computed data; conducting a principal component analysis, a canonical discriminant analysis, or a neural network, on said data to establish a baseline calm or rest period set of scores and a stress period set of scores; measuring the said at least one physiological parameter of said individual during an image presentation period of time; repeating said time segmenting, said histogram or Fourier analysis, and said standardizing steps on said measured physiological data for said image presentation period of time; applying said vectors from said conducting step to said image data to produce an image set of scores which are compared with said baseline and stress sets of scores; and determining whether said presented image is activating, deactivating, or neutral based on said comparison.