Language and theory of mind in autism spectrum disorder: the relationship between complement syntax and false belief task performance.

Lancioni et al. (2009) asked if grammar skill helps autistic children pass false-belief tasks. They tested sentence complement syntax (sentences like "Mom thinks the cookie is in the jar"). Kids also tried two classic ToM tasks: a location-change story and an unexpected-contents story.

The team compared autistic children with matched typical peers. They looked for links between syntax scores and each false-belief task.

Stronger syntax went hand-in-hand with passing the location-change task in the autism group. The same link showed up in typical kids, but only in the ASD group was the effect large enough to matter.

No link appeared for the unexpected-contents task in either group. In short, grammar helps with some false-belief stories, but not all.

Neitzel et al. (2021) found the opposite pattern in Down syndrome: verbal short-term memory predicted false-belief success, but syntax did not. The contradiction is useful—it hints that the grammar–ToM link may be autism-specific rather than universal.

Schuwerk et al. (2015) moved the question to adults with ASD. They used eye-tracking to show that a quick peek at the real outcome can normalize anticipatory looking on an implicit false-belief task. Together, the two studies suggest both language and brief experience can nudge ToM, but in different ways and at different ages.

Nejati et al. (2021) add another piece: visual-spatial skills also predict ToM in autistic youth. So syntax is one of several cognitive levers, not the only one.

If a client struggles with location-change false-belief tasks, check their use of sentence complements like "She thinks the ball is under the box." Targeting these grammar forms during natural play or story time may give ToM a small boost. Keep the task in mind: syntax training seems less useful for unexpected-contents tasks, and other factors—visual-spatial skills or working memory—may matter more for different kids. Use quick probes, then match your language goals to the task that needs help.