Brief report: repetitive behaviors in young children with autism spectrum disorder and developmentally similar peers: a follow up to Watt et al. (2008).

Leaf et al. (2012) watched toddlers and preschoolers with autism and same-age typical peers. They counted how often each child did things like hand flapping, lining up toys, or staring at fans. Kids were matched by mental age, not birthday, so the groups had similar thinking skills.

Children with autism showed more repetitive actions than the matched typical kids. Still, the two groups overlapped; some typical toddlers also flapped or lined up toys a lot. Frequency alone could not clearly separate who had autism.

Suda et al. (2026) later saw the same pattern using eye-tracking: kids with autism looked longer at looping cartoon motions, and the gaze time lined up with parent reports of repetitive play at home. The results extend B et al.'s finding into a new, easy-to-measure marker.

Kirby et al. (2016) filmed families at home and showed when repetitive behaviors popped up most. Hyper-sensitive reactions happened during adult-led routines like tooth-brushing, while sensory seeking came out during free play. B et al.'s lab snapshot now has real-life timing added to it.

Wang et al. (2021) seems to clash at first: they found almost a quarter of kids with autism actually preferred social, non-repetitive videos. The difference is method: B et al. counted any visible stereotypy, whereas Tianbi measured each child's looking preference. Both can be true—a child may flap yet still watch people more than patterns.

Do not rely on a single count of flaps or spins to decide if a toddler needs an autism evaluation. Pair your checklist with eye-tracking or home-context notes when possible. And remember, a child who shows few repetitive actions in clinic might still reveal them during dressing or free play, so ask caregivers about daily routines.