Dissociable Stimulus- and Response-Driven Serial Dependence Effects in Auditory, Visual, and Audiovisual Motion Judgments

Motion perception relies on merging immediate sensory input with prior experience. This concept leads to serial dependence effects (SDEs), where present judgments are swayed by prior information. Researchers investigated SDEs in auditory, visual, and audiovisual motion-direction discrimination tasks, employing aggregate psychometric data and trial-level statistical models to discern the distinct impacts of prior stimuli and responses.

In unisensory auditory trials (57 participants), an attractive SDE was observed, meaning judgments favored the direction of previous stimuli. Conversely, repulsive SDEs were noted in visual tasks (48 participants), where judgments leaned away from preceding stimulus directions. The audiovisual-cued condition exhibited no overall SDE, but a closer examination of trial-level data unveiled a more intricate pattern.

Both unisensory and audiovisual conditions showed repulsive SDEs when the prior stimulus direction was visual, indicating that visual factors consistently impacted judgments. Moreover, the prior response produced attractive SDEs exclusively when visual cues were crucial to the task. In the audiovisual-cued trials, the lack of a net shift in psychometric measures correlated with a counterbalancing interaction between attractive response-history effects and repulsive visual stimulus-history effects, rather than a complete absence of serial dependence.

The study concludes that motion perception involves separate, yet simultaneous, mechanisms. One involves a visual adaptation-like influence from prior stimuli, while the other is a task-dependent aspect tied to decision-making influenced by prior responses.