First, the rise of safetyism in the 1980s and 1990s hit boys harder than girls, because boys engage in more rough-and-tumble play and more risky play. When playtime was shortened, pulled indoors, and over-supervised, boys lost more than girls. The second psychological effect is the result of boys taking up online multiplayer video games in the late 2000s and smartphones in the early 2010s, both of which pulled boys decisively away from face-to-face or shoulder-to-shoulder interaction.
