Researchers at the University of Washington Medical School equipped 330 children, two months to four years old, with digital recorders that captured everything the children heard and said during the day. The recorders were worn one day per month for up to two years.

The study found that TV is:
• Associated with significant reductions in child vocalizations, vocalization duration, and conversational turns.
• Associated with a decrease of 770 words the child heard from an adult during the recording session. This represented an average 7% decrease in words heard.
• Leading to significant reductions in both adult female and male word counts. From 500 to 1,000 fewer adult words were spoken per hour of audible television.

The articles goes onto to provide tips and resources for parents and caregivers as well as recommendations. Read it here.