Timing storytime to maximise children's ability to retain new vocabulary

Shared storybook reading is a key aid to vocabulary acquisition in childhood. However, word learning research has tended to use unnaturalistic (explicit) training regimes. Utilising a storybook paradigm, we examine whether children (particularly those with weaker vocabulary) are more likely to retain new words if they learn them closer to sleep. Parents read their child (5-7ys, n=237) an alien adventure story that contained 12 novel words with illustrations, at one of two training times: at bedtime or 3-5hrs before bedtime. Using on-line tasks, parents tested their child’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: children showed overnight improvements in their ability to produce and comprehend new words when tested again the next day, and 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 hours before, than at, bedtime. These ecologically valid findings are consistent with theories that characterise 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.