General maturational lag as an essential correlate of early-onset psychosis.

James et al. (1981) wrote a theory paper. They warned that many autism studies mix up two things. One is the autism itself. The other is simply being younger or slower to mature.

The authors said you must track both mental age and calendar age. If you skip this step, you may blame autism for effects that are just delayed growth.

The paper did not test people. It looked at past work and found a pattern. Studies that ignored age often reached shaky conclusions.

The team urged future researchers to control age or risk a confound. In plain words, check that the result comes from autism, not from being little.

Later papers took the advice. Chien et al. (2018) studied teens and young adults with ASD. They split participants into tight age bands and still found shorter P3a brain waves linked to sensory issues. The careful age control let the signal stand out.

Nevin et al. (2005) also listened. They compared late-elementary and middle-school autistic children. The older group still showed a weak N4 semantic wave. Because age was held constant, the team could say the language gap persists into early adolescence.

Vivanti (2015) echoed the same worry in a different area. That paper warned that mixing up ability and willingness confounds imitation screening in one-year-olds. Both papers share one theme: separate the real trait from the developmental stage.

Before you run an assessment, write both calendar age and mental age on your data sheet. If you compare clients, match them on these numbers first. This simple step keeps your treatment decisions clean and stops you from chasing problems that may vanish with time.