Theory of mind abilities in young siblings of children with autism.

Shaked et al. (2006) tested theory-of-mind skills in preschool siblings of autistic children. All kids were neurotypical and aged three to five years.

The team gave standard false-belief and perspective-taking tasks. They compared scores to same-age children with no autistic siblings.

Siblings of autistic kids passed the tasks just as often as controls. Group averages showed no meaningful difference.

Within each group, only the siblings linked better receptive language to higher ToM scores. Controls did not show this pattern.

Toth et al. (2007) looks like the opposite result. They saw language, IQ, and social delays in 18-month-old siblings of autistic children. The gap is age: Karen studied toddlers, Michal studied preschoolers. Early delays can later catch up.

Peterson (2005) ran similar lab tasks but with autistic children. Autistic kids failed false-belief tests while siblings in Michal’s study passed. This supports the idea that ToM problems are tied to the autism diagnosis, not family risk alone.

Boucher (2012) review warns that false-belief tasks miss real-life interaction skills. Michal’s null lab result fits that warning: passing a lab test does not guarantee everyday social ease.

You can reassure parents that preschool siblings are unlikely to inherit specific ToM deficits. Still, track each child’s language growth; it may drive their social learning. Use natural play, not just lab tasks, to spot subtle social hiccups. If a toddler sibling shows early language lag, start language-rich play now rather than waiting for false-belief failure later.