Limits on Introspection

Abstract

Which cognitive processes are accessible to conscious report? To study the limits of conscious reportability, we designed a novel method of quantified introspection, in which subjects were asked, after each trial of a standard cognitive task, to estimate the time spent completing the task. We then applied classical mental-chronometry techniques, such as the additive-factors method, to analyze these introspective estimates of response time. We demonstrate that introspective response time can be a sensitive measure, tightly correlated with objective response time in a single-task context. In a psychological-refractory-period task, however, the objective processing delay resulting from interference by a second concurrent task is totally absent from introspective estimates. These results suggest that introspective estimates of time spent on a task tightly correlate with the period of availability of central processing resources.

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

“…However, even at long SOA the PSE was substantially larger than RT2 (i.e., participants overestimated RT2 by 335 ms). This finding contrasts with previous introspective PRP studies that reported IRT2 being generally smaller than RT2 Corallo et al, 2008;Marti et al, 2010; but see , for slight deviations from this pattern) and suggests that participants cannot accurately estimate their RT2 even when the two tasks are temporally separated and thus do not compete for access to central resources.…”

“…That is, in the PRP task the conscious perception of S2 is disrupted by the central processing of Task 1 (Corallo et al, 2008;Marti et al, 2010). This explanation implies that timing is relatively intact under dual-task conditions and that the unawareness of the PRP effect occurs because only the conscious parts of Task 2 processing can be timed (see Marti et al, 2010).…”

“…The standard finding in this paradigm is that reaction time to the second stimulus (RT2) dramatically increases with decreasing SOA (i.e., the PRP effect). Previous introspective PRP studies reported a striking limitation of introspection in this paradigm: subjective estimates of RT2 (introspective RT2, IRT2) did not reflect the objective PRP effect but were constant across SOAs , 2015Corallo, Sackur, Dehaene, & Sigman, 2008;Marti, Sackur, Sigman, & Dehaene, 2010).…”

“…Figure 2 shows predicted psychometric functions for discrimination of RT2 at short and long SOA (plotted against absolute duration of comparison intervals) separately for the two hypotheses that participants are either unaware or aware of the PRP effect. If, as previous results suggest (Corallo et al, 2008;Marti et al, 2010), participants are unaware of the PRP effect, then psychometric functions for RT2 at short and long SOA should superimpose-that is, PSE and discrimination threshold should not differ between the two SOA conditions. Note that this prediction holds irrespective of whether the unawareness of the PRP effect is caused by a conscious perception bottleneck or reflects a temporal context effect.…”

“…To collect IRTs in the PRP paradigm, previous studies mostly used the so-called method of quantified introspection Corallo et al, 2008;Marti et al, 2010; for an exception, see , who used reproduction), which was established by Corallo et al (2008) in their first introspective PRP study. In this method, participants indicate their RT estimate on a visual analogue scale (VAS) that represents a certain, more or less arbitrary, RT range and is labeled with millisecond values.…”