Assessment of stereotypic and self-injurious behavior as adjunctive responses.

The team used a multielement design to test if stereotypy and self-injury pop up as adjunctive behaviors. Adjunctive means the responses happen because of the schedule, not the item itself.

They ran fixed-time (FT) food delivery with kids who had developmental delays. No task demands, just free snacks on a timer.

They watched who rocked, flapped, or hit themselves right after each delivery. The goal was to see if the schedule alone made these behaviors spike.

Stereotypy did rise after some deliveries, but only for some kids. It looked like schedule-induced licking in rats: extra behavior caused by the timing.

Self-injury stayed flat. It did not follow the same adjunctive pattern.

The authors say stereotypy and self-injury may ride on different environmental tracks.

Van Houten et al. (1980) warned that SIB definitions carry too much baggage and urged us to study ecological antecedents. Jarrold et al. (1994) took that call and ran a clean test: they isolated the FT schedule as one antecedent.

Cerutti et al. (2004) showed that a boy’s body rocking was powered by the visual feedback he made. C et al. found a second motor: the clock, not the sight. Both papers tell us to test multiple reinforcers before we treat.

Houston et al. (1987) argued that self-stim is automatic. Their view fits the stereotypy bump here, but not the flat SIB line. Together they hint that automatic reinforcement may be stronger for stereotypy than for self-harm.

When you run FT reinforcement—like edible schedules during toilet training or DRO probes—watch for a sudden jump in stereotypy. If you see it, the schedule may be the culprit, not boredom or task difficulty.

Self-injury that shows up during FT is less likely to be adjunctive, so keep hunting for pain, escape, or sensory pay-offs.

Try a quick reversal: pause the FT and see if stereotypy drops. If it does, thin the schedule or add matched stimulation before problem behavior climbs.