Shared storybook reading is a key aid to vocabulary acquisition during childhood. However, word learning research has tended to use unnaturalistic (explicit) training regimes. Using a storybook paradigm, we examined whether children (particularly those with weaker vocabularies) are more likely to retain new words if they learn them closer to sleep. Parents read their children (5- to 7-year-olds; N = 237) an alien adventure story that contained 12 novel words with illustrations at one of two training times: at bedtime or 3–5 h before bedtime. Using online tasks, parents tested their children’s ability to recall the new words (production) and associate them with pictures (comprehension) immediately after hearing the story and again the following morning. As hypothesized, we replicated two findings. First, children showed overnight improvements in their ability to produce and comprehend new words when tested again the next day. Second, children with better existing vocabulary knowledge showed larger overnight gains in new word comprehension. Counter to expectations, overnight gains in comprehension were larger if the story was read 3–5 h before bedtime rather than at bedtime. These ecologically valid findings are consistent with theories that characterize word learning as a prolonged process supported by mechanisms such as consolidation and retrieval practice, with existing vocabulary knowledge acting as an important source of variability in retention. The findings provide preliminary evidence that encountering new words in stories later in the day (but not too close to sleep) may help to harness vocabulary growth and may be more beneficial than leaving shared storybook reading just for bedtime.

共享故事书阅读是儿童时期词汇习得的关键辅助手段。然而，单词学习研究倾向于使用非自然（显式）的训练机制。使用故事书范式，我们检查了儿童（尤其是那些词汇量较弱的儿童）是否更有可能在接近睡眠时学习新单词。父母阅读他们的孩子（5 到 7 岁；N = 237) 一个外星人冒险故事，包含 12 个带插图的新词，在两个训练时间之一：睡前或睡前 3-5 小时。父母使用在线任务测试孩子在听完故事后立即回忆生词（生产）和将它们与图片联系起来（理解）的能力，并在第二天早上再次测试。正如假设的那样，我们重复了两个发现。首先，当第二天再次测试时，孩子们在产生和理解新单词的能力方面表现出一夜之间的提高。其次，拥有更好现有词汇知识的孩子在新词理解方面表现出更大的隔夜收益。与预期相反，如果在睡前 3-5 小时而不是在睡前阅读故事，那么一夜之间的理解收益会更大。这些生态上有效的发现与将单词学习描述为由巩固和检索练习等机制支持的长期过程的理论一致，现有词汇知识是保留变化的重要来源。研究结果提供了初步证据，表明在当天晚些时候（但不要太接近睡眠）在故事中遇到新词可能有助于利用词汇量增长，并且可能比只在睡前阅读共享故事书更有益。