Trial-by-trial updating of an internal reference in discrimination tasks: Evidence from effects of stimulus order and trial sequence

Abstract

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.

Temporal discrimination of one’s own reaction times in dual-task performance: Context effects and methodological constraints

“…However, as already outlined in the Introduction, this misperception can also be explained by an internal reference account. Accordingly, for the comparison task participants might rely not only on the RT2 from the current trial but on an internal reference based on the current and all previous RT2s (e.g., Dyjas et al, 2012). Under mixed SOA conditions such an internal reference would integrate the information from all trials irrespective of SOA.…”

“…A famous example of such context effects is the Vierordt effect (Lejeune & Wearden, 2009;Vierordt, 1868): Within a certain range of presented intervals, relatively long intervals are underestimated and relatively short intervals are overestimated. Recent explanations for such context effects differ in their exact mechanism, but they all share the idea that not only the current trial information but also the temporal context is taken into account when participants provide duration estimates or comparison judgments (Bausenhart et al, 2016;Dyjas, Bausenhart, & Ulrich, 2012;Shi et al, 2013).…”

“…In fact, it is possible to explain the previously observed null effect of SOA on IRT2 with recent contextual timing accounts. For example, when participants provide their RT2 estimate in a given trial they might rely on an internal reference (Bausenhart et al, 2016;Dyjas et al, 2012) of all their RT2s, instead of relying on only the currently produced RT2. If in the mixed SOA context this internal reference combines all RT2s irrespective of SOA, this would result in a central tendency effect on IRT2 similar to the Vierordt effect.…”

Humans don’t time subsecond intervals like a stopwatch.

“…Hence in Experiment 3 we reversed the presentation order of the standard and target intervals so that the standard interval was always presented first. This adaptation also tends to generate a higher degree of precision on interval timing tasks (Dyjas, Bausenhart, & Ulrich, 2012).…”

“…For example, there is evidence suggesting that participants typically form an averaged internal standard, preferentially for the first comparison stimulus (Dyjas et al, 2012). inventive formulation.…”