空间再定向任务中心理表征的多样性——来自虚拟现实实验的证据

成人和儿童完成空间再定向的具体过程与内在机制一直是研究者们关注的问题，在空间中是否形成了关于环境的整体表征是其中的一个关键。研究者们的观点并不一致，研究结果也提供了不同的证据。使用传统的空间再定向任务在此问题上难以得到明确的结论。本研究采用虚拟现实技术，让被试在虚拟现实环境中观察所在空间，然后直接向被试呈现空间的俯视视角并要求完成位置再认。通过对正确率和反应时的模式分析，发现被试反应可以划分为三种类型：整体的、独立于视角的心理表征（各方向均为高正确率低反应时）；整体的、依赖于方向的心理表征（正确率和反应时在不同方向上差异显著）和视角匹配的心理表征（各方向上均为低正确率）。三种不同的表征形式在人群中同时存在，并且在同一个体身上表现出不稳定性。

The Variety of Position Representation in Reorientation: Evidence from Virtual Reality Experiment

The cognitive mechanisms of spatial reorientation in adults and children have long been hotly debated issues, among which whether individuals could form a holistic representation of navigating space is a key question. So far, there is still no consensus about how individuals maintain the information about their spatial surroundings. Some theories propose that people can form a cognitive map which is an abstract and orientation-free representation of the entire space, while some researchers argue that people can use the image-matching strategy to relocate the target, and a holistic representation of the space is not necessary in reorientation.
The present study aimed to reveal what strategy participants would use in the relocated task. Using the virtual reality technology, we allowed participants to observe the environment from both aerial and ground perspectives. Thirty-four participants first learned the target position in a square enclosure from the ground perspective. Then they were tested with four aerial views of the learning enclosure, and the aerial views varied in their orientation, in which the right position was at TOP, RIGHT, BOTTOM, and LEFT respectively.
Based on their accuracy, we divided participants into 3 group:absolute accuracy (the accuracy was 100%), high accuracy (the accuracy was more than 50% and less than 100%), and low accuracy (the accuracy was no more than 50%).
Reaction time analyses showed that the absolute accuracy group responded quickly in all the orientations, indicating that they might form a holistic and orientation-free spatial representation. In contrast, participants in the high accuracy group were faster in responding to the target position at the top of the display while they were slower in responding to the target position at the bottom of the display, which indicated that they formed a holistic and orientation-specific spatial representation. The low accuracy group was excluded from the analyses because a large proportion of their reaction time data was missing. Participants in this group might use the image-matching strategy in reorientation, which may lead to their failure to complete the present task.
Moreover, we found that, for most participants, their accuracies varied in different enclosures, which showed that they might choose different spatial strategies in different time. This result demonstrated that the same individual may rely on more than one type of spatial representation and one's choice of spatial strategies may fluctuate over time. the three kinds of space representation all exist in human's space representation. People do not choose the same strategy for all the time.
In sum, there are three types of spatial representations in spatial orientation:the abstract and orientation-free spatial representation, the entire and orientation-specific spatial representation. and the image-matching representation. There is clear individual difference on spatial representations and the spatial representation is not consistent.