On Possible Models of Attention in Signal Detection

This paper is concerned with two different mechanisms of attention in auditory signal detection. One alters the width of a Gaussian filter (or attention band), whereas the other changes the tuning. that is. the placement of its center. To formalize these mechanisms, we first consider auditory energy-detection. To explore the effect of a randomly tuned filter, both unifonn and normal density distributions of its center frequency arc investigated. Formulas for predicting signlll detection performance in 21Fe experiments are derived for the different cases resulting from these hypotheses, and examples of psychometric functions are computed. The results reveal striking differences between the two mechanisms. Widening the auditory filter not only reduces sensitivity hut also steepens the resulting psychometric functions. In contr;lst, changing the filter luning causes psychometric functions to naltcn.