Parent-reported early symptoms of autism spectrum disorder in children without intellectual disability who were diagnosed at school age.

Goodwin et al. (2019) asked parents to look back and list early signs they saw before their child’s autism diagnosis. Some kids were found early. Others were not flagged until grade school. The team wanted to know if the late-found group had truly looked different as toddlers.

They compared parent memories of the two groups. All children had average IQ. No child had an intellectual disability.

The late-diagnosed children had almost the same number of early red flags. Social slips were the most common clue. Repetitive play or odd interests were rarely the first thing parents noticed.

The gap between the groups was small. Subtle social misses, not big rituals, were the main historical hint.

Pilgrim et al. (2000) saw the opposite pattern. In their infant sample, later-autism kids showed large social gaps on 16 of 19 items. Anthony’s smaller, school-age group shows the same trend but in miniature. The difference is magnitude, not direction.

Lemcke et al. (2013) also found weak, scatter-shot early signs at 6 and 18 months. Their null result lines up with Anthony’s small effect. Together they warn that toddler screens alone can miss subtle presentations.

Parikh et al. (2018) add why diagnosis can slide: kids with known language delays and higher family income get flagged almost two years sooner. Anthony shows the missed kids did have clues—just quiet social ones—so asking the right parent questions matters as much as checklists.

If you wait for clear repetitive behavior, you may wait too long. Ask parents about early turn-taking, eye contact, and joint attention even when language looks fine. A quick parent interview can surface the soft social gaps this study highlights, speeding referral and saving years of lost intervention time.