Discriminality of statistically independent Gaussian noise tokens and random tone-burst complexes

Hanna (1984) has shown that noise tokens with a duration of 400 ms are harder to discriminate than noise tokens of 100 ms. This is remarkable because a 400-ms stimulus potentially contains four times as much information for judging dissimilarity than the 100-ms stimulus. Apparently, the ability to use all information in a stimulus is impaired by some kind of limitation, e.g. a memory limitation (cf. Cowan 2000) or a limitation in the ability to allocate attentional resources (cf. Kidd and Watson 1992). In a first experiment, this study examined the influence of stimulus duration and bandwidth of Gaussian noise tokens on the ability to perform an auditory discrimination task. In a second experiment, the amount of potential information in a stimulus was decoupled from its duration in order to more carefully examine the properties of the memory or attention limitation that results in the discrimination impairment. Finally, a computational model that limits the amount of perceptual information is introduced as an attempt to model the findings of the first and second experiment.