The effect of concurrent task load on stimulus over-selectivity.

Reed et al. (2005) ran four lab tests with college students who do not have autism.

Each student had to pick the correct picture while also doing a second task like counting clicks.

The team wanted to see if extra mental work made students focus on only one part of a picture.

When the second task was added, students ignored most cues and locked onto just one.

The harder the side task, the narrower their attention became.

This shows that limited brain power, not autism, can drive stimulus over-selectivity.

Rosenthal et al. (1980) first saw over-selectivity in autistic kids who favored one sense, like only looking at lights.

Reed et al. (2005) later proved the same narrow focus can be created in typical adults by piling on load.

The two studies look opposite—autism vs. no autism—but they agree: fewer mental resources mean more tunnel vision.

Grainger et al. (2017) also added memory load to autistic kids and found no extra harm, showing the effect can cap once load is high enough.

If a learner is glued to one cue, first check for hidden load before calling it an autism trait.

Cut background noise, drop extra instructions, and teach one sense at a time.

Keep early discrimination tasks lean; add complexity only after the skill is solid.