Variety is not the spice of life for people with autism spectrum disorders: frequency ratings of central, variable and inappropriate aspects of common real-life events.

Loth et al. (2010) asked boys with and without autism to rate everyday events.

They used short stories about things like going to a restaurant.

Kids marked which parts always happen, which might change, and which would be weird.

The autism group was less accurate at spotting the changeable parts.

They often treated flexible details as fixed rules.

Poor scores linked to weaker theory-of-mind and stronger autism traits.

Reed et al. (2013) saw the same rigidity in low-functioning kids during a card-sort switch.

DeCarlo (1985) found autistic preschoolers were less bothered by shifting visual cues, an early hint that variable input is processed differently.

Dugdale et al. (2000) and Galizio et al. (2020) later showed you can teach autistic learners to choose or produce variety when reinforcement is clear, proving the rigidity is changeable.

Together the picture is: difficulty noticing negotiable details drives repetitive behavior, but ABA can teach flexible responding.

Your high-functioning client may argue "we must sit here" because he truly thinks the seat is a fixed rule, not a detail that can vary.

Start by explicitly labeling which parts of a routine are "same" and which can "change.

Use lag schedules and multiple-exemplar training to reinforce those variable choices, turning abstract flexibility into concrete responses you can reinforce.