學校禁用手機：有用，但不是速效藥

Banning mobile phones in schools has become hugely popular around the world. But the largest study yet suggests the benefits may take longer to appear than many people expect. Researchers from Stanford and three other American universities looked at more than 43,000 middle and high schools across the United States over three years. They compared schools that required students to lock their phones in special pouches for the whole school day with schools that did not. The bans worked in one obvious way: students used their phones much less during school hours. However, the effect on test scores was close to zero on average. There was also little change in attendance, attention in class or online bullying. The most interesting finding was how things changed over time. In the first year after a ban, discipline problems actually rose and students reported lower wellbeing – perhaps because they were frustrated at losing their phones. By the third year, however, discipline had returned to normal, and student wellbeing was higher than before the ban. One of the researchers said phone-free schools were "not a simple or quick fix". Another described the study as only a first step. The message for schools seems to be that patience is needed: the benefits of a ban may only become clear after students have adjusted to it.