title: Allocentric information is used for memory-guided reaching in depth: A virtual reality study.
abstract: Previous research has demonstrated that humans use allocentric information when reaching to remembered visual targets, but most of the studies are limited to 2D space. Here, we study allocentric coding of memorized reach targets in 3D virtual reality. In particular, we investigated the use of allocentric information for memory-guided reaching in depth and the role of binocular and monocular (object size) depth cues for coding object locations in 3D space. To this end, we presented a scene with objects on a table which were located at different distances from the observer and served as reach targets or allocentric cues. After free visual exploration of this scene and a short delay the scene reappeared, but with one object missing (=reach target). In addition, the remaining objects were shifted horizontally or in depth. When objects were shifted in depth, we also independently manipulated object size by either magnifying or reducing their size. After the scene vanished, participants reached to the remembered target location on the blank table. Reaching endpoints deviated systematically in the direction of object shifts, similar to our previous results from 2D presentations. This deviation was stronger for object shifts in depth than in the horizontal plane and independent of observer-target-distance. Reaching endpoints systematically varied with changes in object size. Our results suggest that allocentric information is used for coding targets for memory-guided reaching in depth. Thereby, retinal disparity and vergence as well as object size provide important binocular and monocular depth cues.
authors: Justus-Liebig-University, Experimental Psychology, Otto-Behaghel-Str. 10F, 35394 Giessen, Germany.
authors: Mathias
authors: M
authors: Klinghammer
authors: TU Chemnitz, Institut für Physik, Reichenhainer Str. 70, 09126 Chemnitz, Germany. Electronic address: immo.schuetz@physik.tu-chemnitz.de.
authors: Immo
authors: I
authors: Schütz
authors: Queen's University, Centre for Neuroscience Studies, 18, Stuart Street, Kingston, Ontario K7L 3N6, Canada. Electronic address: Gunnar.Blohm@QueensU.ca.
authors: Gunnar
authors: G
authors: Blohm
authors: Justus-Liebig-University, Experimental Psychology, Otto-Behaghel-Str. 10F, 35394 Giessen, Germany. Electronic address: katja.fiehler@psychol.uni-giessen.de.
authors: Katja
authors: K
authors: Fiehler
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D003198:Computer Simulation; D003290:Convergence, Ocular / Q000502:physiology; D003463:Cues; D003867:Depth Perception / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory; D011939:Mental Recall; D009068:Movement / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance; D013028:Space Perception / Q000502:physiology*; D015357:Vision Disparity / Q000502:physiology; D055815:Young Adult
keywords: Allocentric; Depth cues; Memory-guided reaching; Reference frames; Virtual reality