Amy Nathanson and Eric Rasmussen from Ohio State University studied maternal responsiveness and mother-child interactions of 73 mother-child pairs as they read together, played with toys together and watched TV together.
In the study, the average mother was married, in their early 30s, had a bachelor's degree and half were not employed. The children were ages 16 months to 6 years.
The pairs were randomly assigned to one of the three activities for 10 minutes. A researcher then offered the pair all three activities and left them for a further 20 minutes.
The study, published in Human Communication Research, found when reading a book with their children mothers used a more active communication style, bringing the child into contact with words they may not hear in everyday speech, thereby improving their vocabulary and grammatical knowledge, while watching TV resulted in significantly fewer descriptions and positive responses than mothers playing with toys.
"Mothers who are responsive to their infant's communication promote a positive self-perception for the child as well as fostering trust in the parent. Positive responses help the child learn that they can affect their environment," Nathanson said in a statement.
"However, if maternal responsiveness is absent, children learn that their environment is unpredictable and may become anxious, knowing that their bids for attention or help may be ignored."