A new study says brain development can be affected in kids 3 to 5 years old. The analysis was revealed this week in 'JAMA Pediatrics.'. It says that the brain's white matter can be affected if children stare at screens for more than one hour a day without parents around. This area is associated with skills such as literacy and language improvement. This is important because the brain is developing the most rapidly in the first five years. , Lead author Dr. John Hutton, via study. That’s when brains are very plastic and soaking up everything, forming these strong connections that last for life, Lead author Dr. John Hutton, via study. A hour of screen time per day without any adults is what is recommended by the American Academy of Pediatrics. For the study, an MRI was used on 47 healthy brains of pre-kindergarteners. The kids were also given a cognitive test, which analyzed how much screen access they had. Results went on to show that kids with over one hour had more underdeveloped white matter. On average, the lead author of the study, Dr. John Hutton, says these particular subjects used over two hours of screen time daily. He adds that the study's results are relative and more tests are needed. Hutton says the effects could add up and possibly hinder children as they grow.