Simultaneous recognition of two spatial-frequency components.

A two-frequency two-response paradigm was employed. The stimulus on any trial was a compound grating containing two sinusoidal components of different spatial frequencies where the contrast in one or both components could be zero. The observer gave two responses each indicating confidence that one of the two components had been presented with contrast greater than zero. If these responses are assumed to be related to outputs of spatial-frequency channels according to specified recognition linking hypotheses, then channel properties such as bandwidth, negative influences, correlation of noise, and additivity can be inferred. Possible modifications of spatial frequency channel models are discussed.