That is, the lack of serial dependence might have reflected a reduction in the encoding of the other feature dimension, rather than a lack of the report of this dimension.Įxperiment 1 task and results. Consequently, feature-based attention might have attenuated the perceptual or memory encoding of the unattended dimension.
#SERIAL VISION ADALAH TRIAL#
However, it should be noted that the study used a precue paradigm in which the relevant feature dimension on a given trial was known to participants prior to stimulus onset. A core finding was that, even though participants saw both the variance and the direction, serial dependence in visual variance occurred only when participants had reported visual variance on the previous trial. The participants in this study saw a random-dot kinematogram (RDK) and reported either the mean or the variance of the dot directions on a given trial.
However, because participants were frequently required to report the target feature, it is possible that participants prepared a response even if none was required on the current trial, and that some aspect of response preparation produced the serial dependence effect.Ī recent study used a stimulus with two feature dimensions and tested whether serial dependence was present for one feature dimension when the other feature dimension had been reported on the previous trial (Suárez-Pinilla et al., 2018). These studies showed that serial dependence was present even when the target feature had not been reported on the previous trial, suggesting that serial dependence can be produced by the mere encoding of the previous-trial stimulus. Some studies, however, have included a condition in which no explicit response was required on some trials, which could potentially unconfound the perception and report of the target feature (Czoschke, Fischer, Beitner, Kaiser, & Bledowski, 2019 Fischer & Whitney, 2014 Suárez-Pinilla, Seth, & Roseboom, 2018). Most previous studies of serial dependence required participants to report a single target feature dimension on every trial, which confounds the perception of this feature with the report of the feature. Together, these findings indicate that postperceptual processes play a critical role in serial dependence and that the mere encoding of the previous-trial target is not sufficient to produce the serial dependence effect.
When we used the same response modality for both motion and color reports in Experiment 3, we found significant serial dependence effects following both color-report and motion-report trials, but the effect was significantly weaker following color-report trials. Experiment 2 confirmed that this pattern of results was not driven by the difficulty of the color task. In Experiment 1, we found a serial dependence effect for motion only when participants had reported the direction of motion on the previous trial, and not when they had encoded the direction of motion but reported the color of the stimulus. We assessed serial dependence for motion perception as a function of which feature dimension had been reported on the previous trial. The to-be-reported dimension was indicated by a postcue after stimulus offset, so participants were required to encode both features of every stimulus. To distinguish between these possibilities, we designed a task in which participants reported either the color or the direction of a set of colored moving dots on each trial. In the present study we asked whether encoding the previous-trial stimulus is sufficient to produce this serial dependence effect, or whether the effect also depends on postencoding processes. The reported perception of a visual stimulus on one trial can be biased by the stimulus that was presented on the previous trial.
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