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The research behind our books

Every Lamp & Kin book is written for one child, at one age. Here is what child-development research says about how young children follow a story, and what we do because of it. Where the research is thin, we say so.

Made for how children listen

Our books are read aloud. A grown-up reads; the child listens and looks at the pictures. So we write for what a child can follow by ear at each age, not for what they could read on their own.

Children understand far more than they can read. Through elementary school, a child’s listening comprehension sets the ceiling on their reading comprehension,1 and listening stays ahead of reading until about grades 6 to 8.2

Book language is richer than everyday talk, too. In one study, picture books held 1.72 times as many different words as the speech adults use with young children.3 So we don’t water the words down; we keep them clear.

That’s also why we don’t write to a reading level. Reading scores are built for children reading alone; picture books, which are read aloud, are often marked “AD”, for adult directed.4 You tell us your child’s age, and we write for one of three bands: 2–3, 4–5 or 6–8. If your child already reads on their own, the words move up a band. The story’s tricks and surprises stay with their age.

What changes with age

Children change fast between two and eight. For each part of a book, here is what the research says, and what we do at each age.

Story shape

Stories grow up with children. In one classic study, 25 of 30 stories told by two-year-olds were a heap of things or a simple sequence, not yet a plot.5 From about age six, the classic shape (a problem, some tries and an ending) is the most common way children tell a story.6

When children listen, they hold on to the events that cause other events. That was true at every age studied, and it grew stronger with age.7 In preschoolers, working out a character’s goal, what they do about it and how they feel all went with understanding the story better.8 The youngest children also lean on the order things are told in, so a story told out of order is harder for them to follow.9

  • Ages 2–3

    One simple happening, or a pattern that repeats and builds. Every page makes sense on its own. Everything is told in the order it happens, and the ending says plainly how it all worked out.

  • Ages 4–5

    One goal, said in words early on, with up to three tries toward it. One thread from start to end, with no side stories and no flashbacks. The ending says plainly how it worked out.

  • Ages 6–8

    Two to four episodes and a full story arc. The hero can fail, make a new plan and try again; by six, children follow a character’s goals as they listen.10 At most one small side story, and at most one short flashback, clearly signposted.

Tricks and surprises

A trick only works if you know that someone else can believe something that isn’t true. Psychologists call this theory of mind: understanding that other people think, want and know different things from you. It grows a lot between two and six.

A large review of studies found that at 30 months, children answered these “wrong belief” questions incorrectly more than 80% of the time. At 44 months (about three and a half), half got them right, and a year later about three in four did.11 Knowing that two people can want different things comes much earlier, and hiding a feeling (smiling while sad) comes later: in one study of children aged about 3 to 6½, 95% understood different wants, but only 32% understood a hidden feeling.12 Understanding what one person thinks another person thinks usually arrives at about 5 or 6,13 and by about six, children can tell what sarcasm and irony really mean.14

  • Ages 2–3

    No story that turns on a trick, a disguise or someone believing something untrue, and nobody hides how they feel. Surprises for the reader are fine (“It was a cat!”), and so are characters who want different things.

  • Ages 4–5

    A character can believe something untrue, or fall for a simple trick, only when the words say so plainly: “Bear thought the box was empty. But Mouse was inside!” Hidden feelings are always said out loud. No irony or sarcasm.

  • Ages 6–8

    Tricks, surprises and hidden feelings are welcome. A story about what one character thinks another thinks is fine when the words make it clear. Gentle jokes and irony too, but the story never depends on them.

Words on each page

No study sets the right number of words for a page, so this is where the research is thinnest. The American Speech-Language-Hearing Association suggests books “with large pictures and a few words on each page” for toddlers.15 A children’s book editor’s rule of thumb: books for under-threes run up to about 300 words, the classic picture book about 300 to 500, and books over 500 words are usually for older children.16 We use these as guides.

Children’s own sentences average about three and a half words at age three and about four and a half to five words at six to eight.17 Children understand more than they say, so our sentences run a little longer than that. In primary grades, explaining a new word while reading added to what children learned from hearing the story again.18

  • Ages 2–3

    About 8 to 20 words a page, and 120 to 250 in the whole book. Short sentences of about 3 to 7 words. Everyday words, and a few new ones shown in the picture.

  • Ages 4–5

    About 25 to 45 words a page, and 300 to 500 in the book. Sentences of about 6 to 10 words, with the odd “because” or “when”. A few richer words, each made clear by the sentence around it.

  • Ages 6–8

    About 65 to 90 words a page, and up to about 900 in the book, with longer sentences and richer words. To be honest, that’s shorter than many published picture books for this age: the 14 we measured had a median of about 1,140 words.19 Our pages hold what fits in the picture at a size that’s easy to read aloud.

Repetition and rhyme

Three-year-olds who heard the same story three times learned its new words; children who heard three different stories with the same new words did not. It was a small study, of 16 children.20 Children aged 2 to 4 also remembered new words better from a rhyming version of a story than from one that didn’t rhyme,21 and best of all when the new word was the rhyme they could predict at the end of a line.22

  • Ages 2–3

    A refrain: one short line that comes back again and again, ideally on at least half the pages. Rhyme where it comes naturally, never forced. A book made to be read again and again.

  • Ages 4–5

    A refrain that comes back a few times is encouraged. Each richer word comes back at least twice. Rhyme is welcome, never forced.

  • Ages 6–8

    Refrains and rhyme are optional at this age. The story itself does the carrying.

Pictures

Two-year-olds who looked at the parts of a picture showing the key story events understood the story better than children who looked elsewhere.23 Three-and-a-half-year-olds learned fewer new words when they had to find the thing named across two pictures at once instead of one.24 And for first and second graders reading on their own, extra decorative detail drew their eyes away from the words and lowered how much they understood.25

We found no study that says how many people belong in one picture, so those numbers are our own judgment.

  • Ages 2–3

    One or two named characters in each picture where the story allows: the one the words are about, big and clear. Simple backgrounds. One picture per page turn, never a page of little pictures.

  • Ages 4–5

    About two or three characters in a picture. A simple setting with the things the story uses, and few things it doesn’t.

  • Ages 6–8

    Richer settings and room for more people, but the detail stays tied to the story.

Pictures that match the words

While a child listens, their eyes are on the picture. So the picture has to show what the words say.

In a study of 41 children aged about 4 to 6, a picture that matched the words helped them retell the story much more than a picture that didn’t.26 Children that age look most at the parts of a picture the words are talking about at that moment.27 A picture that disagrees with the words isn’t just a small mistake; it gets in the way of the story.

That’s why we check every page: the right people, doing what the words say, at the right time of day, with the things the words name. If they don’t match, the picture is painted again.

How we keep ourselves honest

Rules only matter if they’re kept. Every book is checked against them as it’s made, before anything is printed.

  1. Before the full story is written, we check the plot against your child’s age. A plot that needs a trick or a hidden belief your child can’t follow yet is rewritten, or we choose another storyline.

  2. We count the words on every page and look at sentence length, harder words and the refrain. A page with too many words for your child’s age is shortened.

  3. Every picture is checked against its page: who is in it, what they’re doing, the time of day and the things the words name. A picture that disagrees with its words is painted again, and if it still isn’t right, a person on our team looks at it before you ever see it.

  4. For children under four, no page has a cluster of little pictures: one picture for each page turn.

  5. The words are set at a size that’s easy to read aloud, and never over a face.

  6. Then you read every page. Change any word, ask for any picture again. Nothing is printed until you approve it.

Where the research is thin

Almost no research looks at what two- and three-year-olds can follow when they listen. Most classic studies of how stories develop look at stories children tell, not stories they hear; children can probably follow more than they can tell, so we treat those ages as a floor.

No study we found sets how many words belong on a page, how many characters a book should have, or how many people belong in one picture. Those numbers are our own careful judgment, and we hold them more loosely than the ones the research backs.

And we leave out claims that haven’t held up, like the popular “30-million-word gap”: a later study that counted the words children hear again didn’t support it.28

References

  1. 1.Biemiller, A. (2003). Oral comprehension sets the ceiling on reading comprehension. American Educator, Spring 2003. www.aft.org/ae/spring2003/biemiller
  2. 2.National Governors Association & Council of Chief State School Officers (2010). Common Core State Standards for English Language Arts, Appendix A: Research supporting key elements of the standards. NGA Center and CCSSO. web.archive.org/web/2016id_/http://www.corestandards.org/assets/Appendix_A.pdf
  3. 3.Montag, J. L., Jones, M. N., & Smith, L. B. (2015). The words children hear: Picture books and the statistics for language learning. Psychological Science, 26(9), 1489–1496. doi.org/10.1177/0956797615594361
  4. 4.MetaMetrics (n.d.). Lexile codes. Lexile Hub. hub.lexile.com/lexile-codes
  5. 5.Applebee, A. N. (1978). The child's concept of story: Ages two to seventeen. University of Chicago Press. archive.org/details/childsconceptofs0000appl_i5o9
  6. 6.Peterson, C., & McCabe, A. (1983). Developmental psycholinguistics: Three ways of looking at a child's narrative. Plenum Press. archive.org/details/developmentalpsy0000pete
  7. 7.van den Broek, P., Lorch, E. P., & Thurlow, R. (1996). Children's and adults' memory for television stories: The role of causal factors, story-grammar categories, and hierarchical level. Child Development, 67(6), 3010–3028. doi.org/10.1111/j.1467-8624.1996.tb01900.x
  8. 8.Tompkins, V., Guo, Y., & Justice, L. M. (2013). Inference generation, story comprehension, and language skills in the preschool years. Reading and Writing, 26(3), 403–429. doi.org/10.1007/s11145-012-9374-7
  9. 9.Blything, L. P., Davies, R., & Cain, K. (2015). Young children's comprehension of temporal relations in complex sentences: The influence of memory on performance. Child Development, 86(6), 1922–1934. doi.org/10.1111/cdev.12412
  10. 10.Lynch, J. S., & van den Broek, P. (2007). Understanding the glue of narrative structure: Children's on- and off-line inferences about characters' goals. Cognitive Development, 22(3), 323–340. doi.org/10.1016/j.cogdev.2007.02.002
  11. 11.Wellman, H. M., Cross, D., & Watson, J. (2001). Meta-analysis of theory-of-mind development: The truth about false belief. Child Development, 72(3), 655–684. doi.org/10.1111/1467-8624.00304
  12. 12.Wellman, H. M., & Liu, D. (2004). Scaling of theory-of-mind tasks. Child Development, 75(2), 523–541. doi.org/10.1111/j.1467-8624.2004.00691.x
  13. 13.Miller, S. A. (2009). Children's understanding of second-order mental states. Psychological Bulletin, 135(5), 749–773. doi.org/10.1037/a0016854
  14. 14.Glenwright, M., & Pexman, P. M. (2010). Development of children's ability to distinguish sarcasm and verbal irony. Journal of Child Language, 37(2), 429–451. doi.org/10.1017/s0305000909009520
  15. 15.American Speech-Language-Hearing Association (n.d.). Communication milestones. ASHA. www.asha.org/public/developmental-milestones/communication-milestones/
  16. 16.Underdown, H. (n.d.). Writing and publishing board books. The Purple Crayon. www.underdown.org/board-books.htm
  17. 17.Rice, M. L., Smolik, F., Perpich, D., Thompson, T., Rytting, N., & Blossom, M. (2010). Mean length of utterance levels in 6-month intervals for children 3 to 9 years with and without language impairments. Journal of Speech, Language, and Hearing Research, 53(2), 333–349. doi.org/10.1044/1092-4388(2009/08-0183)
  18. 18.Biemiller, A., & Boote, C. (2006). An effective method for building meaning vocabulary in primary grades. Journal of Educational Psychology, 98(1), 44–62. doi.org/10.1037/0022-0663.98.1.44
  19. 19.Renaissance Learning (n.d.). Accelerated Reader BookFinder (word counts for the 14 books we measured). Renaissance. www.arbookfind.com
  20. 20.Horst, J. S., Parsons, K. L., & Bryan, N. M. (2011). Get the story straight: Contextual repetition promotes word learning from storybooks. Frontiers in Psychology, 2, 17. doi.org/10.3389/fpsyg.2011.00017
  21. 21.Read, K., Macauley, M., & Furay, E. (2014). The Seuss boost: Rhyme helps children retain words from shared storybook reading. First Language, 34(4), 354–371. doi.org/10.1177/0142723714544410
  22. 22.Read, K. (2014). Clues cue the smooze: Rhyme, pausing, and prediction help children learn new words from storybooks. Frontiers in Psychology, 5, 149. doi.org/10.3389/fpsyg.2014.00149
  23. 23.Kaefer, T., Pinkham, A. M., & Neuman, S. B. (2017). Seeing and knowing: Attention to illustrations during storybook reading and narrative comprehension in 2-year-olds. Infant and Child Development, 26(5), e2018. doi.org/10.1002/icd.2018
  24. 24.Flack, Z. M., & Horst, J. S. (2018). Two sides to every story: Children learn words better from one storybook page at a time. Infant and Child Development, 27(1), e2047. doi.org/10.1002/icd.2047
  25. 25.Eng, C. M., Godwin, K. E., & Fisher, A. V. (2020). Keep it simple: Streamlining book illustrations improves attention and comprehension in beginning readers. npj Science of Learning, 5, 14. doi.org/10.1038/s41539-020-00073-5
  26. 26.Takacs, Z. K., & Bus, A. G. (2018). How pictures in picture storybooks support young children's story comprehension: An eye-tracking experiment. Journal of Experimental Child Psychology, 174, 1–12. doi.org/10.1016/j.jecp.2018.04.013
  27. 27.Takacs, Z. K., & Bus, A. G. (2016). Benefits of motion in animated storybooks for children's visual attention and story comprehension: An eye-tracking study. Frontiers in Psychology, 7, 1591. doi.org/10.3389/fpsyg.2016.01591
  28. 28.Sperry, D. E., Sperry, L. L., & Miller, P. J. (2019). Reexamining the verbal environments of children from different socioeconomic backgrounds. Child Development, 90(4), 1303–1318. doi.org/10.1111/cdev.13072
The research behind our books | Lamp & Kin