Chapter 16

Summary of Auditory and Visual Sensations

This chapter summarizes both auditory and visual sensations including both temporal and spatial aspects of these percepts in each modality. Each temporal and spatial attributes has a corresponding feature in its respective correlation function.

In the auditory modality, temporal factors are associated with the monaural perceptual qualities of pitch, timbre, and duration and changes in sound quality related to first reflection time, and subsequent reverberations. Auditory temporal factors are those parameters that can be derived from features of autocorrelation functions (ACFs). Auditory spatial factors, on the other hand, are associated with the binaural percepts of sound direction in the horizontal plane, apparent source width and envelopment, as well as loudness. Auditory spatial factors are parameters derived from features of interaural correlation functions (IACFs).

In the visual modality, temporal factors are associated with temporal aspects of visual perception, such as perceived rates of flickering lights and oscillating movements, whereas spatial factors are associated with spatial vision, such as the perception of forms and textures. Temporal visual factors are derived from the features of the temporal autocorrelation functions (ACFs) of changing visual signals, and spatial factors are derived from the spatial autocorrelation functions of static visual patterns.

Thus there may exist deep commonalities between the two modalities, both in the structure of their respective perceptual spaces and in possible similarities in the correlation-based neural information processing mechanisms that subserve their respective percepts. It appears that the behavior of a great many auditory percepts and at least a few visual ones can be explained in terms of features of these various correlation-based representations. In more than a few cases, features of correlationbased representations have more obvious and direct connections to perceptual qualities than do their frequency-domain, spectral counterparts.

Cerebral hemispheric specialization may play an important role in accounting for the independent effects that temporal and spatial factors on their corresponding percepts (temporal and spatial sensations). There may be two distinct modes of representation, temporal and spatial, that are lateralized at the cortical level, such that this lateralization may at least partly explain their high degree of functional independence.