Lead
"Reading picture books is good for the brain." "Fifteen minutes of reading a day builds vocabulary." These claims circulate through parenting sections of bookstores and across social media with remarkable consistency.
Most of them travel without a source. Effect sizes are rarely mentioned. If reading aloud really works, how much does it work? Does the way you read matter? How much does the number of books in the house have to do with long-term outcomes?
Fortunately, picture books and the home reading environment are areas where the educational psychology literature has accumulated genuine data. This article uses several meta-analyses and one large international dataset to redraw what the evidence actually shows: it works — and it is also overstated. A position that is less exciting than the marketing, but more accurate.