Interaction and imitation deficits from infancy to 4 years of age in children with autism: a pilot study based on videotapes.

Receveur et al. (2005) watched old family videos of children later diagnosed with autism.

They looked for moments when the child played, copied, or talked with others from birth to four years.

The team rated how often and how well each child showed interaction and imitation skills.

Deficits showed up before the first birthday.

Some children with higher learning scores had milder gaps, while those with lower scores showed bigger problems.

The gaps were already visible in the clips parents filmed at home.

Wan et al. (2019) pooled many similar video studies and found the same early red flags, so the 2005 picture still holds.

Palomo et al. (2022) used the same home-movie trick but coded joint attention instead of imitation; together the two papers map a broad social slump by 9–12 months.

Geurts et al. (2008) pushed the timeline even earlier, spotting eye-contact and affect gaps at six months, showing the cascade starts sooner than Christine’s tapes could catch.

Weissman-Fogel et al. (2015) tested preschoolers live and found kids with ASD need longer imitation demos to notice they’re being copied, giving a practical twist to the early deficit Christine flagged.

If parents mention “he never copied peek-a-boo” or “she didn’t wave back,” believe them. Review any baby videos they have. Look for absent give-and-take, late imitation, and flat shared looks. Note the child’s overall learning level; brighter toddlers may mask some gaps. Use these clues to start turn-taking games and modeled play earlier, and track if the child needs extra time to recognize your copied actions.