Researchers often employ reproduction or forced-choice tasks to assess sequential effects \citep[see][]{Pascucci2023}. In reproduction tasks, participants replicate the perceived attribute of a stimulus. On the other hand, the forced-choice task involves binary responses, requiring participants to judge the perceived stimulus if it is shorter (larger, clockwise) or longer (smaller, anticlockwise) relative to a standard reference. The influence of task-relevant responses on sequential bias does not consistently align with each other using different tasks. For example, reproduction tasks have shown serial dependence linked to prior choices and post-perceptual decisions \cite{Bae2020}, while others demonstrated that serial dependence can occur even without explicit responses in a forced-choice numerosity task \cite{Fornaciai2018}. This discrepancy in evidence raises questions about the consistency of sequential dependence effects across different measurements.
To date, how tasks influence sequential effects has not been systematically investigated. The reproduction and force-choice tasks may use working memory differently. Reproduction may require continuous comparison of the adjusting stimulus to the reference from memory, while the force-choice task only compares the sensory input to the reference once. If force-choice tasks employ other strategies, such as response criteria \cite{Lages_1998}, the impact of task relevance might be minimal.
On this ground, the current study examined how previous task-relevant responses affect temporal sequential effects, exploring if these effects vary with different tasks, specifically the time discrimination and reproduction tasks. We employed the Random Dot Kinematogram (RDK), incorporating two features: motion direction and timing, in a post-cue setup. Participants had to remember its duration and direction, reporting one according to post cues. This post-cueing paradigm required attentive engagement with both features in each trial.
Our primary focus is the sequential effects on duration estimates across trials. We consider trials where participants previously reported duration as task-relevant and those reporting direction as task-irrelevant. To understand how the task type influences carry-over effects in time perception, we employed a time discrimination task in Experiment 1, where participants judged whether the perceived duration was shorter or longer than a standard 1-second reference. In Experiment 2, participants performed a time reproduction task, requiring them to reproduce the perceived duration. We analyzed sequential effects on timing-report trials based on whether the previous trial involved reporting the direction (task-irrelevant) or the time (task-relevant).