三维场景中内隐记忆的编码机制：来自背景提示效应的证据

The visual system of human beings has the ability to cope with the numerous information in a complex visual environment because they can find some rules in the environment according to their previous experience. The acquisition of these experiences is often unconscious. The contextual cueing effect, a facilitating phenomenon when searching for a target embedded in repeated displays, is well suited to study the nature of implicit spatial memory. In the 3D world, we always need to observe the scenes from multiple viewpoints, therefore it is important to know whether the learned knowledge could transfer to a novel viewpoint. The previous study of contextual cueing effect is limited to 2D scenes or single view 3D scenes, to investigate the effect from different perspectives in 3D space could help us to understand the nature of the contextual cueing effect, as well as learn more about the flexibility in implicit memory. This project intends to explore the factors and mechanisms of the transfer of the contextual cueing effect between different perspectives. The specific research issues include the following: (1) Can the context cueing effect be migrated to the non-learning perspective? (2) Whether this process affected by spatial reference information or spatial updates brought by observer’s movement? How do they interact？ What is the mechanism of visual viewpoint flexibility?

在复杂的视觉环境中，个体能够根据经验发现规律，从而快速地定位目标，而这个过程常常是无意识的。背景提示效应(contextual cueing effect)，即在重复呈现的背景中进行视觉搜索能够提高效率的现象，是探究内该隐记忆过程的经典范式。身处三维空间中的我们，常需要从不同的视角（viewpoint）去观察世界，因而从某一视角习得的场景知识能否迁移到新视角是空间记忆的重要课题。先前关于背景提示效应的研究多基于二维空间或单视点的三维场景，通过探讨三维空间中背景提示效应在不同视角间的迁移，不仅能加深对背景提示效应本质的认识，也将对理解内隐空间记忆的灵活性有重要意义。本项目拟探讨三维场景中背景提示效应在不同视角间迁移的制约因素和机制。具体的研究问题包括以下方面：（1）背景提示效应迁移到非学习视角的限制因素？（2）空间参照信息和观察者移动如何影响这一过程？其背后的机制是什么？

背景线索效应是指个体通过对场景中重复信息的无意识加工，并利用其促进在相应场景中行为绩效的现象。大量研究探讨了这种内隐记忆现象产生的机制，然而背景提示效应中编码信息的本质还未探明。本研究使用虚拟现实、ERP、眼动追踪等技术，通过视角变化范式探讨三维仿真场景中背景提示效应中场景编码信息的本质。目前已经发表了标注本项目资助的论文共5篇，其中2篇为SCI，3篇为中文核心，已经投稿或正在成稿的论文1篇、专著1部。通过系列实验，本项目发现，在提供了充足的空间线索后（例如提供充分的空间参照信息、观察者自身移动带来的空间更新等），个体能够将在学习视角习得的内隐行为绩效优势迁移到非学习视角，该结果一定程度上证明了背景提示效应编码的信息不仅是基于机械的视网膜图像，还包含了抽象的空间关系，这一发现有助于深化对内隐记忆的认识。同时，项目研究还发现，在特定搜索试次结束后给予奖赏（内隐奖赏）会对背景提示效应产生较大的促进，并体现在脑电信号中的反馈前负波（SPN）上，该研究进一步证实了背景提示效应可以加工抽象的关系记忆。综上所述，本项目的研究成果有助于揭示背景提示效应这一内隐记忆现象的底层编码单位，同时为内隐记忆和关系记忆的研究提供全新的视角。