Children’s screen time and the impact on cognitive development

Two recently published studies using information from this country’s largest longitudinal study of child development, Growing Up in New Zealand, looked at the prevalence of pre-schoolers’ screen time; identified predictors of higher screen time for children at two years of age; and investigated how pre-schoolers’ screen time could impact executive functions and symptoms of inattention and hyperactivity.

University of Auckland Doctoral Researcher in the School of Psychology, Maria Corkin says the recently published research provides a detailed picture of New Zealand children’s growing use of screen media and parenting practices that may be linked to higher levels of screen use for young children.

“Digital technologies and the widespread use of multiple screens in the household, not just television, has been a relatively recent development. The children in the Growing Up in New Zealand study can provide us with valuable insights into the use of screens and their potential effects on child health, well-being and development,” Mrs Corkin says.  

The first study examined the prevalence of screen time and the family behaviours that were associated with higher screen time use.

It looked at mother-reported screen time for children at the age of two-years-old and found that the majority of children (66%) had one hour or less of screen time per day.

Mrs Corkin says this meets or is very close to meeting the Ministry of Health guidelines which recommend less than an hour of screen time per day for this age group.

However, around 12% of children spent three or more hours a day on screens.

Mrs Corkin says the study identified specific parenting practices which were related to higher levels of screen time for two-year-olds. These included:

• A “heavy TV environment” in which the TV is on in the same room as a child for long periods, whether they were watching it or not.
• Not having rules about how much time children could spend viewing screens.
• Allowing children to view adult content.

Mrs Corkin says children who always watched screens with their parents had lower overall levels of screen time.

She hopes this information might provide some useful ideas for parents and others supporting families who may be looking for ways to reduce children’s screen time.

“Children up to the age of three are still developing the ability to comprehend screen media so parents often play an important role in mediating the viewing experience for children and supporting their learning,” Mrs Corkin says.

“We’d certainly encourage families to see if they can co-view or co-use screens with their child as often as possible, set time restrictions, minimise the amount of time TV is left on in same room as their child, and avoid letting their child view content meant for adults.”

The second study explored how screen media use at two and four years of age might be related to the development of executive functions and the symptoms of inattention and hyperactivity at four-and-a-half.

Executive functions cover a range of cognitive processes, including inhibitory control, flexible thinking, and working memory.

Mrs Corkin says executive functions support the development of social skills in the preschool years; foster academic competence when children start school; and support success in adult life.

“The preschool years are a period of increased neuroplasticity in which executive functions develop rapidly. It is important to understand more about children’s screen use might be related to executive functions so that we can learn more about the best way to manage preschool children’s screen use to promote the development of these essential cognitive skills.”

The study found that two features of the home environment were associated with poorer executive functions at four-and-a-half years of age:

• A heavy TV environment, when the child was two-years-old, which involved the TV being on in the same room as the child for long periods of time, whether or not they were watching it.
  
• Eating meals in front of the TV