That's the world the McMillan family from Ontario, Canada, decided to live in for a year. Blair, 27, Morgan, 28, and their two sons Trey and Denton, aged five and three, got rid of their cable TV, smartphones, internet, new games console, digital camera, DVD player and sat nav, and instead used an old TV, a radio, old telephones, a VHS video player, an old games console and maps. They decided to try it after seeing how their young children were becoming dependent on technology. They aren't alone.

The word ‘They’ in paragraph 3 refers to _______.