A new processing model for predicting performance on Pascual-Leone's test of M-space

A new model is proposed for explaining children's performance on Pascual-Leone's test of M-space. The model differs from Pascual-Leone's in three regards. (1) It assumes that children do not stop sampling a compound stimulus until every simple stimulus in their field of attention has already been noticed and responded to. (2) It assumes that the probability of sampling different combinations of simple stimuli conforms to the laws of Maxwell-Boltzman statistics rather than Bose-Einstein statistics. (3) It assumes that children's ability to detect all the simple stimuli in a compound stimulus is highly dependent both on the relative saliencies of the simple stimuli and on the length of time for which the compound stimulus is exposed. Using the developmental values of M hypothesized by Pascual-Leone, and standard techniques of computer simulation, the new model is used to generate theoretical performance curves for children at four different age levels and seven different levels of stimulus complexity. It is shown that the predicted performance curves for an exposure time of 5 sec provide a reasonable fit to the data originally reported by Pascual-Leone (1970), and that the predicted performance curves for an exposure time of 10 sec provide a reasonable fit to data obtained more recently by Parkinson (1976). Finally, it is shown that the order of children's responses as well as the number of their responses can be predicted. Two conclusions are drawn. (1) The new processing model offers a viable alternative to the model originally proposed by Pascual-Leone. (2) Regardless of which processing model is employed, the M-values originally postulated by Pascual-Leone are valid.