The following is a summary of “Stronger serial dependence in the depth plane than the fronto-parallel plane between realistic objects: Evidence from virtual reality,” published in the May 2023 issue of Ophthalmology by Tanrikulu, et al.
Previous studies have shown that visual estimates of stimulus features are influenced by the features of previously encountered stimuli, indicating a serial dependence effect. This effect is often associated with how the brain maintains perceptual continuity. However, most studies on serial dependence have focused on simple two-dimensional stimuli. For a study, researchers sought to investigate serial dependence in three dimensions using natural objects in a virtual reality (VR) environment.
In Experiment 1, participants were presented with 3D virtual objects commonly encountered daily and asked to reproduce their orientation. They manipulated the rotation plane of the object and its distance from the observer. They found significant positive serial dependence effects, indicating that participants’ estimates were biased toward the orientation of previously encountered objects. Importantly, larger biases were observed when the object was rotated in-depth and rendered as being further away from the observer. Experiment 2 involved varying the object identity from trial to trial to examine the object specificity of serial dependence. They observed similar serial dependence effects regardless of whether the test item was the same object, a different exemplar from the same object category, or a different object from a separate category. It suggested that serial dependence is not solely dependent on the specific identity of the object.
In Experiment 3, they manipulated the retinal size of the stimulus in conjunction with its distance in the VR environment. They found that serial dependence was primarily influenced by retinal size rather than depth cues provided by VR. This indicated that the increased uncertainty introduced by the third dimension in VR enhances serial dependence.
Overall, the findings suggested that serial dependence was present in three-dimensional perception and is influenced by factors such as object rotation, distance, and retinal size. By studying serial dependence in VR, more accurate insights into the nature and underlying mechanisms of these perceptual biases can be gained.