How mechanisms of perceptual decision-making affect the psychometric function

Abstract

Psychometric functions are often interpreted in the context of Signal Detection Theory, which emphasizes a distinction between sensory processing and non-sensory decision rules in the brain. This framework has helped to relate perceptual sensitivity to the "neurometric" sensitivity of sensory-driven neural activity. However, perceptual sensitivity, as interpreted via Signal Detection Theory, is based on not just how the brain represents relevant sensory information, but also how that information is read out to form the decision variable to which the decision rule is applied. Here we discuss recent advances in our understanding of this readout process and describe its effects on the psychometric function. In particular, we show that particular aspects of the readout process can have specific, identifiable effects on the threshold, slope, upper asymptote, time dependence, and choice dependence of psychometric functions. To illustrate these points, we emphasize studies of perceptual learning that have identified changes in the readout process that can lead to changes in these aspects of the psychometric function. We also discuss methods that have been used to distinguish contributions of the sensory representation versus its readout to psychophysical performance.

Impact of Time Delay in Perceptual Decision-Making: Neuronal Population Modeling Approach

“…For the delays below the critical value, we observe a clear association between the magnitude of the stimulus and the probability of making the correct decision (Figure 4). This result is concordant with classic experiments on perceptual decisionmaking, as typically, a monotonic psychometric curve links the strength of the stimulus with the decision accuracy [17,34]. However, for the synaptic delays exceeding the critical threshold, the system falls into a new dynamical regime and is no longer precise in making decisions.…”

Variability in visual cortex size reflects tradeoff between local orientation sensitivity and global orientation modulation

“…S1), suggesting that the correlation between V1 surface area and orientation perception was robust to the retinotopic-mapping paradigm/stimulus used for measuring the V1 surface area. To test whether this correlation was also robust to the psychophysical paradigm/stimulus used for assessing orientation perception3233, we conducted control experiments where we used cardinally oriented stimuli or a spatial two-alternative-forced-choice paradigm (Supplementary Note 3) to replace the obliquely oriented stimuli and the temporal two-alternative-forced-choice paradigm used in the original experiments. Under cardinally oriented stimuli, we still observed a tradeoff between orientation discrimination sensitivity and orientation contextual illusion magnitude that correlated with the V1 surface area (Fig.…”

Action video game playing is associated with improved visual sensitivity, but not alterations in visual sensory memory

“…Second, initial visual sensitivity may remain unchanged, but sensory information may be retained longer in visual memory, thereby mitigating the natural decay of information in memory buffers as evidence is accumulated toward a particular decision choice. Third, there may be no differences in the initial sensitivity to visual information or in the retention of this information in rapidly decaying sensory memory buffers, but rather decision processes may be enhanced such that AVGPs are able to more quickly or reliably "read out" perceptual information (Gold & Ding, 2012), leading to improved performance.…”