Developmental effects in the cerebral lateralization of autistic, retarded, and normal children.
Autistic kids’ brains stay right-left unspecialized and slow longer than mental-age peers, a gap that lasts lifelong.
01Research in Context
What this study did
The team tested the kids: 20 with autism, 20 with intellectual disability, and 20 typical kids. All were matched on mental age, not birthday age.
Each child listened to clicks in one ear while pressing a button as fast as possible. The test shows which ear and hand the brain favors.
They timed the button presses to see how quickly each group reacted and how strongly one ear dominated the other.
What they found
Autistic kids pressed the button more slowly than both other groups.
They also showed weaker ear dominance, meaning their brains were less specialized to one side.
The delay was bigger than expected for their mental age, pointing to extra cortical slowdown beyond IQ.
How this fits with other research
Burgess et al. (1986) used EEG and found the same slow-wave pattern, a clean conceptual replication.
Wu et al. (2025) ran modern fMRI on large samples and confirmed the lag, so the 1983 result still holds but is now superseded by sharper imaging.
Jouravlev et al. (2020) extended the idea to adults, showing the lateralization gap persists into grown-up life.
Sigman et al. (2005) followed kids for years and saw the delay does not catch up; skills plateau, proving the lag is lifelong, not temporary.
Why it matters
You now have 40 years of evidence that autistic learners process speed and side dominance mature more slowly. Build extra wait time into instructions and let kids use either hand for fine-motor tasks. Track early play and joint attention, because these predict who will keep falling behind.
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02At a glance
03Original abstract
This experiment was designed to determine whether increasing evidence of generalized developmental delay in early-onset psychosis was apparent at a cortical level in autistic children. Using magnitude of dominant ear advantage as an indicator of relative cerebral dominance, unwarned simple reaction time (RT) to monaural presentation of tones was investigated in matched groups of autistic, retarded, and normal children. Analysis of RTs and relative ear advantage as a function of group membership and chronological age indicated that the autistic children showed significant developmental delay in both RT and the establishment of cerebral dominance compared to the control groups. These results thus provide additional evidence of generalized maturational delay at a cortical level in early-onset psychosis, and suggest that the maturational delay of the autistic children is more extensive than the developmental deficits implied by their intellectual impairment.
Journal of autism and developmental disorders, 1983 · doi:10.1007/BF01531358