My husband and I started reading to our son basically as soon as he came home from the hospital, but it was sometimes hard to know which books to choose. After all, sometimes I felt like I was reading to myself. By six months, I’d read him everything from Philosopher’s Stone through Order of the Phoenix to Pat the Bunny.

Despite my love for the Potterverse, my son seemed to get more out of the simple books. This is backed up by a new study published in the journal Child Development, which says the best books for infants offer labels for people and things on the pages.

“When parents label people or characters with names, infants learn quite a bit,” says Lisa Scott, co-author of the study. “Books with individual-level names may lead parents to talk to infants more, which is particularly important for the first year of life.”

Scott’s team brought a group of babies into the lab when they were 6 months old and again three months later. The researchers used eye-tracking and electroencephalogram technology to measure the babies’ attention at both stages.

In between those visits to the lab, the babies were treated to plenty of reading time at home. Moms and dads were asked to read to the babies for 10 minutes every day for the first two weeks, then every other day for the second two weeks and then at a continually decreased rate until the babies were 9 months old.

Two sets of parents got the exact same book—except one version of the book had clear names for the characters (e.g. Fiona, Boris and Jamar) while the other version grouped all the people into a made-up category (e.g. “hitchel”). There was also a control group with babies that didn’t get books.

When the kids returned to the lab, researchers found the babies whose parents read the individual-level name books spent more time focusing on images, and their brain activity recorded via the EEG showed they were differentiating between individual characters.

There are lots of recommendations about reading books to babies, but our work provides a scientific basis for these recommendations and suggests that the type of book is also important,” says Scott, adding it’s a win-win for parents. “It creates an enjoyable and comforting environment for both the parents and the infant and encourages parents to talk to their infants.”

At 2 years old, my son is now older than the babies in Scott’s study, but he still likes books where individual objects and people are named. Just now he’s the one doing the “reading” when he points out objects like balls, cats and milk to me.