An analysis of visual detection by temporal probability summation

The probability of detection by temporal probability summation (TPS) is derived assuming a non-white Gaussian noise process, characterised by a finite second spectral moment λ2; the assumption of stationary noise is discussed with respect to neurophysiological findings suggesting multiplicative noise for individual neurons. The usual white-noise assumption is shown to imply inconsistent detection models. d′-estimates for 2AFC-experiments do not depend on the value of λ2 and do not differ from those derived from the standard SDT-assumptions, in contrast to d′-estimates for yes-no-experiments, which depend on the probability of false alarms. Estimates of properties of a visual channel depend on whether detection is by TPS or temporal peak detection (TPD); it is argued that TPD is not a special case of TPS, and that subjects chose a TPS- or a TPD-strategy depending on experimental conditions.