I, too, had a more-than-passing interest in the garbage truck as a kid; with palpable residual excitement, I can remember peeking through the window shutters of my parents’ front room to watch the vaguely menacing robotic arm jut out, snatch our garbage can, and dangle the can upside down over its back while the trash tumbled out. Why generations of kids have been so transfixed by the trash pickup, though, remains something of a mystery. So I asked parents, kids, child-development experts, waste-management professionals, and even the creator of a kids’ show about an anthropomorphized garbage truck for their insights. Together, we made our way—more aptly, lurched and rumbled our way—toward a unifying theory of why kids are so wild about garbage trucks.

The garbage truck I remember watching out our window as a child—big lumbering hulk, single hungry grabber claw—is known in the waste-management industry as an “automated side loader.” (When I excitedly mentioned to Whitney Schlander that the automated side loader was introduced 50 years ago on the streets of Scottsdale, I discovered this was old news to her and Finn: “We went to the trash-transfer facility last year. Of course,” she said with a laugh. “They have the original one.”) Other varieties in the United States have automated forks on their front to pick up larger trash receptacles such as Dumpsters, while still others depend on human workers to manually pick up, empty, and replace the garbage cans.

When I asked Sheila Williams Ridge, who teaches early-childhood education at the University of Minnesota’s Institute of Child Development, for any insights she could give me on why kids love garbage trucks so much, she thought of her own daughter, now 21. When her daughter was little, Williams Ridge remembered, the weekly arrival of the garbage truck was both dazzling and, in a way, reassuring.

“Humans have always thrived with routine,” she told me. “But children, their memories aren’t long enough. Sometimes, when we’re getting our 3-year-olds dressed for winter, they’re like, ‘I can’t do it!’ And we’re like, ‘You’ve put on snow pants before. You’ve put on boots.’ But for them, it’s so long ago. They don’t remember snow from when they’re 2; it’s new again for them.” So having something happen every week at the same time—and especially something that “seems a little bit magical”—can boost kids’ sense of familiarity with the world, not to mention give them something to look forward to.

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Plus, what the truck is actually doing when it arrives has an air of the forbidden. Despite the fact that kids are frequently discouraged from making messes at home or at school (or perhaps because of that fact), “children love dumping things. They just do,” Williams Ridge said. “So the fact that a truck is coming to do this on purpose, and everyone is happy about it? It’s like, ‘Yes! This is my dream! I just want to dump stuff out, and you let this person do it!’” (The same goes for being noisy: “I think that’s the other thing with a lot of big trucks, and with police cars, fire trucks, snowplows,” she added. “They’re loud, and no one’s complaining about it.”)