MODELING INTENSITY DISCRIMINATION AND DETECTION IN NOISE FOR STIMULI WITH DIFFERENT SPECTRO-TEMPORAL SHAPES

A model combining signal information from multiple frequency-time (f-t) windows is developed to address detection and intensity discrimination performance for stimuli with different spectro-temporal shapes. The model is based on the concept of elementary auditory f-t windows for stimulus analysis in the auditory system. Experiments have shown that this f-t window is a critical band wide and has a duration of about 4 ms at 1 kHz (1 ms at 4 kHz). The spectro-temporal shape of the stimulus determines the number of auditory f-t windows excited in the auditory system. The internal noise (coding acuity) in each f-t window is proportional to the stimulus energy (in accordance with Weber's Law). The information of the different f-t windows involved in the task is combined. Simulations with this model show that, for stimuli with different spectro-temporal shapes and equal total energy, the masked detection threshold is independent of the number of f-t windows, whereas the intensity discrimination threshold decreases if the number of f-t windows increases. These trends match our experimental data.