Main author: Ömer Dağlar Tanrıkulu
Institution or Company: University of Iceland
Co-Authors, Institution or Company:
David Pascucci, Swiss Federal Institute of Technology in Lausanne. Arni Kristjansson, University of Iceland.
Introduction: Perceptual judgments about visual features are biased towards previously encountered stimuli. This bias, called serial dependence, is thought to promote perceptual stability (via memory-supporting mechanisms) in the world, since natural scenes are generally stable from one moment to the next. To date, serial dependence has only been studied using simple 2-dimensional stimuli. Our current study moves the investigation of serial dependence into more natural settings by utilizing Virtual Reality (VR).
Method: Observers were presented with an object commonly encountered in daily life (e.g. a flashlight) and then reported its orientation in an adjustment task within the VR environment. The distance between the observer and the object, and the plane in which the object was rotated (in depth or in fronto-parallel plane), was manipulated. Orientation judgment errors were analyzed as a function of previously encountered orientations.
Results: Orientation judgments were overall biased towards the orientation presented in the previous trials. Larger biases were observed when the object was further away in depth, and also when the object was rotated in depth compared to the fronto-parallel plane. Moreover, larger biases was observed on the current trial when the object in the previous trial was closer to the observer.
Conclusion: Results indicate that the additional uncertainty added by the 3rd-dimension can yield more robust positive serial dependence. Given that such history biases are found to be reduced in patients with schizophrenia, encephalitis or autism, examining such biases in VR can provide more accurate insights into reduced memory-supporting mechanisms in such populations.