In an open-access study of over 2,400 children, just published in JAMA Pediatrics, Professor Sheri Madigan and her colleagues found that the more time young children spend glued to screens, the worse their score on tests of cognitive and emotional development (the widely-used ‘Ages and Stages Questionnaire,’ or ASQ-3).
https://www.treehugger.com/family/children-glued-screens-show-alarming-developmental-delays.html