As part of our ongoing commitment to professional development and technical precision, this month we are exploring the mechanics behind why certain behaviours persist. In Positive Behaviour Support (PBS), we strive to understand the context of an individual’s actions. While our initial assessments often focus on identifying the specific reinforcer maintaining a behaviour, the rate and predictability of that reinforcement—known as the schedule—is what truly determines the strength and durability of the response.

Recognising the Schedule in the Natural Environment

When we first observe a child in their natural setting, we are often walking into a situation where a behaviour of unmet need is already being maintained by a complex, unplanned schedule. In a controlled setting, we might see continuous reinforcement where every single response is reinforced. However, the real world is rarely that consistent. Most behaviours we encounter are maintained on intermittent schedules.

A common challenge in PBS practice is the variable ratio schedule. This occurs when reinforcement is delivered after an unpredictable number of responses. In a home environment, this might look like a child seeking a parent’s attention; they might be ignored several times, but eventually, the parent responds. Because the reinforcement is unpredictable, the behaviour becomes incredibly resistant to change. This persistence is a hallmark of intermittent reinforcement, where the uncertainty of when the payoff will occur actually strengthens the behaviour over time.

Designing Strengths-Based Interventions

Understanding these schedules allows us to move beyond reactive strategies and instead design interventions that lean into a family’s existing strengths. When we introduce a functional replacement behaviour, such as a specific vocal request or a gesture, we are essentially competing with an established, high-strength history of reinforcement. This is where the principles of Applied Behaviour Analysis (ABA) provide a clear framework for change, always through a lens of ethics and social validity.

By utilising differential reinforcement of alternative behaviour (DRA), we can systematically reinforce a new communicative skill while placing the previous behaviour of concern on a much leaner schedule or extinction. In the early stages of teaching a replacement skill, we use a continuous schedule to ensure the child experiences immediate success. As noted by Tiger, Hanley, and Bruzek (2008) in their work on functional communication training, the replacement behaviour must be more reliable and require less effort than the behaviour it is intended to replace. This focus on efficiency ensures that the intervention is socially valid and meaningful for the child's daily life.

Another powerful tool in our toolkit is Noncontingent Reinforcement (NCR). This involves delivering the maintaining reinforcer on a fixed or variable time schedule, regardless of the child's behaviour. A seminal study by Vollmer et al. (1993) demonstrated that by providing attention on a dense, response-independent schedule, practitioners could significantly reduce the motivation for a child to engage in problem behaviour to access that same reinforcer. By proactively meeting the need, the variable schedule previously in place is neutralised. This affirming approach prioritises the individual's dignity and overall quality of life by ensuring their needs are met before they even have to ask.

Moving Toward Sustainability

Once a new skill is firmly established or a behaviour is stabilised through NCR, we can begin the process of schedule thinning. This involves gradually moving from continuous to intermittent reinforcement, such as a variable interval schedule. On a variable interval schedule, reinforcement is available for the first correct response following an unpredictable duration of time.

This transition helps the skill generalise to the natural environment and ensures that the family can maintain progress without needing to reinforce every single instance of the behaviour indefinitely. By carefully managing these transitions, we ensure our interventions are both scientifically robust and practically sustainable. Ultimately, our goal in combining the precision and the values of our discipline is to foster sustainable agency and an enriched quality of life for the people we support.

Dr. Deirdre Kearney

Principal Behavioural Psychologist

The Behaviour Clinic

22nd January 2026

References

Cooper, J. O., Heron, T. E., and Heward, W. L. (2020). Applied Behavior Analysis. 3rd edn. Harlow: Pearson Education.

Tiger, J. H., Hanley, G. P., and Bruzek, J. L. (2008). ‘Functional Communication Training: A Review and Practical Guide’, Behavior Analysis in Practice, 1(1), pp. 16–23.

Vollmer, T. R., Iwata, B. A., Zarcone, J. R., Smith, R. G., and Mazaleski, J. L. (1993). ‘The role of attention in the treatment of attention-maintained self-injurious behavior: Noncontingent reinforcement and differential reinforcement of other behavior’, Journal of Applied Behavior Analysis, 26(1), pp. 9–21.