SINGAPORE - Excessive screen time for young children is linked to impaired brain function and may have detrimental effects that last beyond early childhood and impair future learning, a new study has shown.
The study of 506 children showed that infants who were exposed to more screen time had more “low-frequency” brain waves – a state that is correlated with lack of cognitive alertness.
As the duration of screen time they were exposed to increased, more altered brain activity and more cognitive deficits were measured in the children, and these effects continue after the child reaches eight years old, the study said.
Children with deficits in executive function often have difficulty controlling impulses or emotions, sustaining attention, following through multi-step instructions, and persisting in hard tasks.
The study, conducted by researchers from the National University of Singapore (NUS), the Singapore Institute for Clinical Sciences (SICS), the National Institute of Education, KK Women’s and Children’s Hospital, McGill University, and Harvard Medical School was published on Tuesday in the peer-reviewed medical journal JAMA Pediatrics.
Lead author, Dr Evelyn Law from NUS Medicine and SICS’ Translational Neuroscience Programme, said: “The study provides compelling evidence to existing studies that our children’s screen time needs to be closely monitored, particularly during early brain development.”
The children studied were those enrolled in the Growing Up in Singapore Towards Healthy Outcomes (Gusto) cohort study and have been so since birth.
In a joint statement on Monday, NUS and SICS said the brain of a child grows rapidly from birth until early childhood, but the part of the brain which controls executive functioning, known as the prefrontal cortex, has a longer development period.
Executive functions include the ability to sustain attention, process information and regulate emotional states, all of which are essential for learning and school performance, it said.
It added that the advantage of this slower growth in the prefrontal cortex is that the gaining and shaping of executive function skills can happen across the school years until higher education.
The statement added: “However, this same area of the brain responsible for executive functioning skills is also highly vulnerable to environmental influences over an extended period of time.
“This study points to excessive screen time as one of the environmental influences that may interfere with executive function development.”
Prior research suggests that infants have trouble processing information on a two-dimensional screen, it said.
“When watching a screen, the infant is bombarded with a stream of fast-paced movements, ongoing blinking lights and scene changes, which require ample cognitive resources to make sense of and process. The brain becomes ‘overwhelmed’ and is unable to leave adequate resources for itself to mature in cognitive skills such as executive functions.”
The statement added that the researchers are also concerned that families which allow very young children to have hours of screen time often face additional challenges. These include stressors such as food or housing insecurity, and parental mood problems.
More work needs to be done to understand the reasons behind excessive screen time in young children, it said, and further efforts are necessary to distinguish the direct association of infant screen use versus family factors that predispose early screen use.
Professor Chong Yap Seng, dean of NUS Medicine and chief clinical officer at SICS, said: “These findings should not be taken lightly because they have an impact on the potential development of future generations and human capital.
“With these results, we are one step closer towards better understanding how environmental influence can affect the health and development of children. This would allow us to make more informed decisions in improving the health and potential of every Singaporean.”