Ability profiles in children with autism: influence of age and IQ.
In autism, verbal IQ catches up to non-verbal IQ by school age, but writing stays hard—so keep writing supports in every intervention plan.
01Research in Context
What this study did
Mayes et al. (2003) looked at how IQ and school skills line up with age in kids with autism. They tested verbal IQ, non-verbal IQ, reading, spelling, and math in a cross-section of children. The goal was to map typical ability patterns for different age bands.
What they found
Preschoolers with autism showed verbal IQ scores that lagged behind their non-verbal IQ scores. By school age the two IQ scores moved closer together. Visual reasoning stayed strong while writing stayed weak, no matter the child's overall IQ level.
How this fits with other research
Barthelemy et al. (1989) showed that IQ scores stay stable after age four when you keep the same test. Dickerson's age-linked profiles fit that finding: the gaps they saw are real, not test noise.
Fields et al. (1991) found big IQ jumps in preschool after one school year. Dickerson's data suggest those early gains may shrink the verbal-non-verbal gap as kids move into school age.
Festinger et al. (1996) reported that autistic children score lower on daily-living skills than IQ-matched peers with ID alone. Dickerson adds that writing is the academic skill most likely to lag, giving you two clear targets for intervention: adaptive skills and written output.
Why it matters
When you test a preschooler with autism, expect verbal scores to trail non-verbal scores. Plan language-rich interventions and re-test after school entry to see if the gap closes. Keep writing goals in every plan, even for kids with average non-verbal IQ. Use visual cues and typing supports to bypass the chronic writing weakness these data predict.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Add a 5-minute writing probe to your next assessment and trial a keyboard or tablet for written tasks.
02At a glance
03Original abstract
To understand the effect of IQ and age on ability in children with autism, psychological data were analyzed for 164 3- to 15-year-olds with autism (IQs 14-143). As age increased, so did IQ, which probably reflects both an actual increase in IQ over time and the likelihood that brighter children are diagnosed later. Early in life, 67 percent had normal motor and delayed speech milestones. Verbal IQ continued to lag behind non-verbal IQ during the preschool years. By school age, the gap between verbal and non-verbal IQs had closed. Visual reasoning exceeded graphomotor scores for all children, and surpassed IQ for most. Graphomotor scores were significantly below IQ for both high-IQ groups. For school-age children with low IQs, math, spelling, and writing scores were consistent with IQ and reading was above IQ. School-age children with high IQs had average reading, math, and spelling scores and a weakness in writing.
Autism : the international journal of research and practice, 2003 · doi:10.1177/1362361303007001006