Scientists call obsessions like Erin’s an “intense interest.” Researchers don’t know exactly what sparks them — the majority of parents can’t pinpoint the moment or event that kicked off their kids’ interest — but almost a third of all children have one at some point, typically between the ages of 2 and 6 (though for some the interest lasts further into childhood). And while studies have shown that the most common intense interest is vehicles — planes, trains, and cars — the next most popular, by a wide margin, is dinosaurs.
Source: A Psychological Explanation for Kids’ Love of Dinosaurs
