"Letting a toddler spend lots of time using screens may delay their development of skills such as language and sociability," BBC News reported.
Researchers followed over 2,000 children in Canada from birth up to the age of five, with screen time assessments performed from age two years onwards. Screen time was defined as time children spent watching or interacting with any type of screen-based devices, such as tablets, TVs or smartphones.
Overall they found that increased screen time was generally associated with poorer developmental test scores. However, the study can't prove that screen time is directly responsible for the child's developmental test scores.
A child's development is likely to be influenced by a complex interplay of factors. It is very difficult to pull these factors apart and work out the role of a single factor like screen time.
Recent advice published by the Royal College of Paediatrics and Child Health avoided making specific recommendations on screen time limits, citing a lack of evidence. But they say that for younger children "face-to-face social interaction is vital to the development of language and other skills, and screen-based interaction is not an effective substitute for this".
They also advise "that screens are avoided for an hour before the planned bedtime".