study 8-10 hours they're spending on their phones 8-10 hours they're spending on their phones Journal of Behavioral Addictions 8-10 hours they're spending on their phones 90 phút mỗi ngày cho việc nhắn tin According to a Baylor University study spend an average of eight to ten PsychCentral spend hours 8-10 hours spend on their cellphones study spend hours Journal of Behavioral Addictions How excessive cellphone use could be hurting students (Journal of Behavioral Addictions) 8 to 10 hours