Spatial updating according to a fixed reference direction of a briefly viewed layout

Abstract

Three experiments examined the role of reference directions in spatial updating. Participants briefly viewed an array of five objects. A non-egocentric reference direction was primed by placing a stick under two objects in the array at the time of learning. After a short interval, participants detected which object had been moved at a novel view that was caused by table rotation or by their own locomotion. The stick was removed at test. The results showed that detection of position change was better when an object not on the stick was moved than when an object on the stick was moved. Furthermore change detection was better in the observer locomotion condition than in the table rotation condition only when an object on the stick was moved but not when an object not on the stick was moved. These results indicated that when the reference direction was not accurately indicated in the test scene, detection of position change was impaired but this impairment was less in the observer locomotion condition. These results suggest that people not only represent objects' locations with respect to a fixed reference direction but also represent and update their orientation according to the same reference direction, which can be used to recover the accurate reference direction and facilitate detection of position change when no accurate reference direction is presented in the test scene.

Figure 1

A. egocentric updating model, B. allocentric updating model. In B. the reference directions are illustrated by the single-direction arrow. The angles between v₁, v₂, v₃ and the reference directions indicate the bearings of v₁, v₂, v₃ in terms of the reference directions.

Figure 2

Experiment design in Experiments 1–2

Figure 3

Correct percentage in detecting position change as the function of cause of view change in Experiment 1. (Error bars are ±1 standard error of the mean, as estimated from the analysis of variance.)

Figure 4

Correct percentage in detecting position change as the function of target object and cause of view change in Experiment 2. (Error bars are ±1 standard error of the mean, as estimated from the analysis of variance.)

Figure 5

Experiment design in Experiment 3.

Figure 6

Correct percentage in detecting position change as the function of target object and cause of view change in Experiment 2. (Error bars are ±1 standard error of the mean, as estimated from the analysis of variance.)