Emotional pictures are generally better remembered than neutral ones. However, in recent years, researchers have proposed that this emotional memory enhancement is not a unitary phenomenon but a compound process involving two opposite effects, especially when the memorized picture is a complex scene. On the one hand, emotional information may selectively enhance the memory of the emotionally arousing central item within the scene while impairing the memory of the peripheral background, leading to the “emotion-induced memory trade-offs”. On the other hand, emotion can enhance memory in a non-selective manner across central and background information, resulting in the “emotion-induced memory broadening”. Studies show that the occurrences of these two effects hinge on various factors related to stimulus properties and memory processes. As to the stimulus-relevant factors, negative and positive valences of the memorized stimuli are more likely to drive the trade-offs and the broadening effects, respectively. Moreover, the intensity of the center-background association within the affective scene can also influence the selectivity of memory enhancement. Concerning the memory processes, task manipulations at the encoding (e.g., passive viewing vs. strategical processing), consolidation (e.g., sleep vs. no sleep), and retrieval (e.g., recognition vs. cued-recall) phases may differently affect the selectivity of emotion-induced memory enhancement. Hitherto, the cognitive and neural mechanisms underlying the emotional memory trade-offs and broadening effects remain unclear. There is a debate on whether the memory trade-offs effect is an automatic process independent of attention narrowing and post-stimulus elaboration. Besides, a few studies reveal that a core neural network involving the amygdala, hippocampus, fusiform, temporal pole, and inferior frontal gyrus is associated with the trade-offs effect, with the activation of some other brain regions dependent on valence and arousal levels of the stimuli. Further research needs to compare the mechanisms of the emotion-induced memory broadening with those of the trade-offs at both behavioral and neural levels, particularly taking a closer look at the automaticity of and the forms of memory representations involved in these effects. In addition, extending these effects from spatial to other (e.g., temporal) dimensions may help elucidate how emotional signals selectively enhance the memory of complex scenes from different aspects.

情绪图片能够比中性图片产生更好的记忆效果。然而近年研究发现，对于复杂场景图片，情绪诱发的记忆增强并非单一的过程，而包含两个相反的现象：情绪信息既可能选择性地增强场景中具有情感色彩的中心的记忆，并带来背景记忆的下降，诱发情绪记忆权衡效应；也可能同时增强中心和背景记忆，诱发情绪记忆拓宽效应。两种现象的发生取决于记忆信息特性（情绪效价、中心-背景联结程度）及记忆过程（编码、巩固和提取）相关的诸多因素，而其背后的机制仍未明晰。当前该领域存在情绪记忆权衡是否是一种不依赖于情绪中心吸引注意的自动化过程的争论，另有少数研究考察了与记忆权衡效应相关的脑网络，而针对记忆拓宽效应机制的研究仍较为匮乏。未来需从行为和神经层面，对比情绪诱发的记忆权衡与拓宽效应的发生机制，针对二者的自动化特性、涉及的记忆表征形式等问题深入研究，并将这些效应拓展至空间之外的维度，以系统揭示情绪信息选择性增强记忆现象背后的深层原因。

国家自然科学基金（32171059和31830037）;; 科技部科技创新2030-“脑科学与类脑研究”重大项目（2021ZD0204200）;; 中国科学院先导专项（XDB32010300）;中国科学院前沿科学重点研究项目（QYZDB-SSW-SMC030）;中国科学院青年创新促进会;; 中央高校基本科研业务费专项资金资助项目