Retrieval practice is well-established as a powerful tool for reinforcing long-term learning. Most previous research has concentrated on the effectiveness of overt retrieval, involving recalling information from memory and generating overt responses by writing, typing, or speaking aloud the retrieved information. Here we ask whether covert retrieval, involving mentally retrieving information without producing overt responses, can enhance learning and consolidate long-term memory, and whether it does so as effectively as overt retrieval. The current meta-analysis integrated data from 2560 participants across 18 studies to investigate the magnitude, boundary conditions, and underlying mechanisms of the covert retrieval effect and the relative efficacy of overt and covert retrieval. The results showed that covert retrieval enhances learning to a small but significant extent (g = 0.23), and its effectiveness is moderated by several factors including provision of corrective feedback, control strategy, and retention interval. The results support the additional exposure and desirable difficulty theories to jointly account for the covert retrieval effect. The meta-analysis also found that overt retrieval is more effective than covert retrieval (g = 0.17), with the effect size of this additional benefit being moderated by the mode by which covert retrieval is performed. The results support the truncated search and desirable difficulty explanations of the relative benefit of overt compared to covert retrieval. Overall, the documented findings provide practical implications for optimizing learning and teaching practices and highlight several important directions for future research.

检索练习是加强长期学习的有力工具。以前的大多数研究都集中在显性检索的有效性上，包括从记忆中回忆信息并通过书写、打字或大声说出检索到的信息来产生显性反应。在这里，我们询问隐性检索，包括在心理上检索信息而不产生明显的反应，是否可以增强学习和巩固长期记忆，以及它是否与显性检索一样有效。目前的荟萃分析整合了 2560 项研究中 18 名参与者的数据，以调查隐蔽检索效应的大小、边界条件和潜在机制，以及显性和隐性检索的相对疗效。结果表明，隐蔽检索在较小但显著的程度上增强了学习 （g = 0.23），其有效性受几个因素的调节，包括提供纠正反馈、控制策略和保留间隔。结果支持附加暴露和理想难度理论共同解释隐蔽检索效应。荟萃分析还发现，显性检索比隐性检索更有效 （g = 0.17），这种额外好处的效应大小受到隐性检索模式的调节。结果支持截断搜索和对显性检索与隐性检索相比的相对优势的理想难度解释。总体而言，记录在案的研究结果为优化学习和教学实践提供了实际意义，并突出了未来研究的几个重要方向。