In psychophysics, participants are often asked to discriminate between a constant standard and a variable comparison. Previous studies have shown that discrimination performance is better when the comparison follows, rather than precedes, the standard. Prominent difference models of psychophysics and decision making cannot easily explain this order effect. However, a simple extension of this model class involving dynamical updating of an internal reference accounts for this order effect. In addition, this Internal Reference Model (IRM) predicts sequential response effects. We examined the predictions of IRM in two duration discrimination experiments. The obtained results are in agreement with the predictions of IRM, suggesting that participants update their internal reference on every trial. Additional simulations show that IRM also accounts for the negative sequential effects observed in single-stimulus paradigms.

No abstract

No abstract

No abstract

When participants can temporally prepare for a visual target stimulus, responses to this stimulus are faster and more accurate. Recent accounts attribute these effects either to an earlier accumulation of stimulus information or to an increased rate of information sampling. The present study examines whether temporal preparation induces such changes in the dynamics of information processing by investigating speed-accuracy trade-off (SAT) functions. Shorter onsets and higher asymptotes of the estimated SAT functions were found for high temporal preparation conditions. These results provide evidence for an earlier onset of information accumulation in the visual system when temporal preparation is high.