关键词: 空间记忆, 虚拟场景, 内在参照系, 朝向

Abstract: The intrinsic spatial frame of reference system (FoRs) theory suggests that people memorize objects’ locations according to a FoRs based on object-to-object relationships. Li & Zhang (2011) demonstrated that the orientation-coincidence affected the construction of intrinsic FoRs in spatial memory with real symmetric scene applied. However, no significant difference was found in the chances to be the dominant axis of intrinsic FoRs between the symmetric axis and the coincident orientation during the retrieval phase in the aforementioned study. In the present study, two experiments were conducted to investigate participants’ responses to virtual scenes during both the coding and the retrieval phases of memory, under the orientation-coincidence and orientation-predominance conditions respectively. Forty-eight participants took part in this study, and each of them finished one experiment only. Each experiment included a learning phase and a testing phase. In the learning phase, participants studied a virtual symmetric scene consisted of seven objects from a single viewpoint, while their eye movements were recorded using the German SMI iView X Hi-Speed Eye Tracking System (sampling rate=1250Hz, refresh rate=100Hz). Subsequently in the testing phase, participants were required to perform the partial-scene-recognition (PSR) task in which they needed to judge whether the directional relationship in the partial scene was the same as the learned scene. In Experiment 1 (that is orientation-coincidence condition), there were seven virtual buildings that shared the coincident orientation in the learning scene. While in Experiment 2 (that is orientation-predominance condition), a different scene was learned, in which one building with clear orientation was surrounded with six objects with no orientation. In both experiments, the object orientation was set at the direction of 135°. All the participants observed the scenes along the 315° direction. The symmetric axis was set at the axis of 0°-180°. The difference between the observed percentage and the a priori percentage of inter-object eye movements and the response time in PSR task was analyzed using ANOVA. In Experiment 1, for the difference between the observed percentage and the a priori percentage of inter-object eye movements, results showed no significant difference between the coordination system including the coincident orientation of objects (45°, 135°, 225°, and 315°) and that including the symmetric axis (0°, 90°, 180°, and 270°). And no significant difference was found between the mean response time to partial scenes aligned with the direction of coincident orientation and that aligned with the symmetric axis. In Experiment 2, the coordination system including the symmetric axis caused a significantly larger difference between the observed percentage and the a priori percentage of inter-object eye movements than the coordination system including the predominant orientation. At the same time, the mean response time to partial scenes aligned with the direction of symmetric axis was significantly quicker than that aligned with the predominant orientation. The results of the two experiments indicated that the orientation-coincidence of the objects in the virtual symmetric scene affected the construction of intrinsic FoRs in virtual symmetric scene. However, different effect was observed under the orientation-predominance condition that participants were inclined to choose the symmetric axis as the intrinsic axis. In conclusion, the influence of objects’ orientations on the intrinsic FoRs is limited to certain circumstances.

Key words: spatial memory, virtual scene, intrinsic frame of reference system, orientation