The acquisition of problem behavior in individuals with developmental disabilities as a behavioral cusp.
Treat the first instance of problem behavior as a behavioral cusp—intervene before it gains powerful reinforcement.
01Research in Context
What this study did
Robertson (2015) wrote a theory paper. It asked: does the first time a child hits, screams, or runs away count as a behavioral cusp?
A behavioral cusp is a small first response that opens big new worlds. Once the child contacts strong escape or attention, the behavior explodes.
The paper says treat that first hit like a cusp. Move fast before the environment starts to pay off.
What they found
The paper did not run an experiment. It lined up the cusp criteria against problem behavior.
Every box was checked. One slap can bring lifelong pay-offs: adult attention, escape from work, even brain relief.
Therefore, the first instance is not a nuisance. It is a gateway.
How this fits with other research
Potter et al. (2013) tested this idea early. They found mild face-slaps and whines that always came right before major aggression. When they treated the mild stuff with attention and break fading, the big blows stayed away. Their data became the legs under the cusp argument.
Kim et al. (2024) extended the warning to kids with autism. They say run A-B-C sheets the moment you see the first odd squeal or bite. Their plan turns the cusp idea into a daily form you can hold.
Neely et al. (2025) push the same urgency after treatment. They call any return of severe behavior a fresh cusp. Have a booster plan ready so the second wave never locks in.
Why it matters
You now have a clock that starts at the very first scream. Treat that sound like a fire alarm, not background noise. Do a quick functional analysis, give a non-contingent break, or teach a replacement the same day. Waiting gives the behavior a raise. Acting fast keeps the child, the family, and your future self out of crisis.
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Run a 5-minute precursor observation during the next work session; if you spot a new whine or slap, start a brief functional analysis and plan reinforcement for the replacement that same day.
02At a glance
03Original abstract
A behavioral cusp has been defined as a behavior change that produces contact with new contingencies with important and far-reaching consequences. The concept of behavioral cusps has most frequently been used to select target skills taught to learners and to evaluate the importance of those skills; however, the concept is equally applicable to behavior changes that bring about important and far-reaching negative consequences. Although it has been acknowledged that socially undesirable behavior change can also qualify as a behavioral cusp, this area of the cusp concept has been under-examined. In this article, an undesirable behavior change, the acquisition of problem behavior in individuals with developmental disabilities, is compared with criteria for behavioral cusps previously identified in the literature. The advantages of viewing problem behavior as a behavioral cusp are outlined, and implications for practice and research from a behavioral cusp approach to problem behavior are provided.
Behavior modification, 2015 · doi:10.1177/0145445515572185