)
with comparable sequential effects for the task-relevant (Time) and task-irrelevant (Direction) conditions in the current duration discrimination task. These findings indicate that prior duration had a noticeable impact on current duration judgment, leading to shifted psychometric curves in both previous time- and direction-reporting conditions. This shift reflects an attractive bias towards the previous duration, resulting in a higher proportion of judgments of the current duration as longer than the standard one-second stimulus when the prior duration was long compared to when it was short. However, sequential effects in the task-relevant (Time) and task-irrelevant (Direction) conditions did not differ significantly.
F(1,23) = 0.098, p = .757, \(\eta_{p}^{2}\) = 0.000),
To examine whether current duration judgments were influenced by preceding responses (decisional carry-over effect), we grouped all time discrimination trials based on participants’ reports (“Short” or “Long”) on the duration in the previous trial. In Figure 2C, we present psychometric curves based on these prior reports. Notably, a distinct difference is evident in the curves concerning prior reports. When participants reported “Long” in the previous trial, the curve shifted leftward compared to when they reported “Short”, indicating an attractive sequential effect toward the prior report. Specifically, participants tended to judge the current comparison durations as “Longer than one second” more frequently after reporting “Long” compared to “Short” reports. The PSE for “Long” and “Short” reports in the previous trial were 0.741 ± 0.045 and 0.898 ± 0.051 s, respectively (Figure 2D). A two-tailed paired sample t-test on the PSE revealed a significant decisional carry-over effect. The PSE was significantly shifted leftward when participants reported “Long” compared to “Short” decisions in the previous trial (t(23)= 3.740, p =.001, d = 0.671).
These findings demonstrate that current duration judgments were influenced by both preceding durations and the decisions made in the previous trials. Specifically, durations presented immediately after long intervals tend to be perceived as longer, while durations following short intervals are perceived as shorter, showing an attractive sequential effect. However, there was no significant difference between trials following the timing discrimination task and the direction adjustment task, suggesting that post-perceptual processes may not be involved in the sequential effect underlying duration discrimination tasks. Furthermore, participants exhibited a significant decisional carry-over effect, meaning they were inclined to continue making “Long” judgments in subsequent duration discrimination tasks when they had reported a stimulus as “Long” in the previous trial, and vice versa for “Short” judgments. However, it is important to note that in the time discrimination task, decisions are categorical, involving dichotomous judgments as either “shorter” or “longer” than one second. It remains uncertain whether these findings from Experiment 1 can be generalized to tasks involving continuous critical dimensions. Therefore, in Experiment 2, we employed the time reproduction task, where participants were required to reproduce the duration of the presented stimulus.