(Konferencja #PDA, Perth, 11 listopada 2025)
Kate Heina is an occupational therapist who has worked with neurodivergent people for 16 years and is also the mother of a child with a PDA profile. In her talk, she focuses on the distinction between capability and capacity, and on aligning expectations with a child’s current regulatory availability.
Starting point
The talk is grounded in Ross Greene’s assumption: “Kids do well if they can.” Difficulty is not interpreted here as willful defiance, but as a sign that the current level of demands has exceeded the capacity available at that moment. Behaviour becomes a communication about whether the child is coping with pressure - both intentional and unintentional.
The nervous system and safety
Kate places this reasoning in neurobiology, drawing on Stephen Porges’ polyvagal theory and the concept of neuroception - the automatic, non-conscious monitoring of the environment for safety.
Important: the autonomic nervous system operates outside conscious control. In this framework, it is not a decision but a physiological state.
When the system detects safety - that is, when it is in a state of safety - access to executive functions becomes possible: learning, planning, communication, and relationship. When threat is detected, the stress response is activated and access to the “thinking part of the brain” becomes limited.
In people with a PDA profile, the threat-detection system may be especially sensitive. Demands, time pressure, loss of control, or violations of autonomy may all be registered as threat cues.
Cumulative stress and the “bucket”
Kate refers to the concept of cumulative stress, described among others by Stuart Shanker. Stress accumulates. The metaphor of the bucket illustrates the total available energy - the capacity to cope with everyday demands.
Demands and pressure act like a running tap. Each additional burden fills the bucket. Stressors accumulate and gradually narrow the window of tolerance - a concept popularized among others by Dan Siegel to describe the range of optimal arousal.
As long as the load remains within the window of tolerance, the child has access to their capabilities. When the bucket overflows, overload appears - in the form of fight, flight, freeze, or shutdown.
Capability versus capacity
Capability means that a given skill exists.
Capacity means that, at a given moment, there are enough regulatory resources available to use that skill. The same person may have more capacity one day and less on another - depending on fatigue, illness, accumulated stress, or previous burdens.
Skills do not disappear. They may become temporarily inaccessible. In that sense, this is about “can’t, not won’t” - not “won’t,” but “can’t.” Capacity depends on the current state of the nervous system, not on willpower.
Aligning expectations
If capacity is variable, expectations must also be flexible. Kate uses the phrase aligning expectations - adjusting expectations to the current available capacity.
This is a move away from increasing pressure and toward adapting demands to the current regulatory state. In practice, it means recognizing how much different tasks “cost,” and when it makes sense to support the child in attempting a harder task (reach up), and when it is better to reduce demands (drop).
Three levels of capacity
Kate proposes three approximate levels of capacity:
1. Very low capacity / Recovery
Capacity is significantly limited. Functioning focuses on basic self-care and the safest possible environment. Expectations are minimal. Recovery takes time and cannot be rushed.
2. Stability
Moderate capacity. It becomes possible to gradually expand the range of safe people, places, and activities.
3. Stretch days
Periods of increased capacity, when more demanding activities become possible. These require limiting other burdens in advance and substantial recovery afterward.
These levels are fluid and can move in both directions.
Monitoring the here and now
In addition to general capacity, it is important to keep checking whether the child is still within their window of tolerance. The question becomes: are we approaching the tipping point of overwhelm?
Early signs of reduced capacity may include:
- procrastination,
- retreat into fantasy,
- increased sensory sensitivity,
- increased need for control,
- changes in communication,
- increased movement and physical tension.
The decision in the moment is whether to support reach up or apply drop. This is not a rigid procedure or algorithm, but a process that requires attention and attunement.
Ending
Balancing capability and capacity is not simple. Mistakes are inevitable. The core assumption remains trust: the child will do things when they can - not when pressure becomes strong enough.
PS. Who does Kate Heina refer to?
Ross W. Greene
A clinical psychologist and creator of the Collaborative & Proactive Solutions (CPS) model. He is the author of the phrase “Kids do well if they can,” which assumes that difficult behaviour stems from missing skills or overload, not from bad intent.
Stephen Porges
A neurophysiologist and creator of polyvagal theory. He describes how the autonomic nervous system responds to cues of safety and threat, and how these responses shape access to cognitive and relational functions.
Dan Siegel
A psychiatrist and researcher in interpersonal neurobiology. He popularized the concept of the window of tolerance, describing the range of arousal in which optimal cognitive and emotional functioning is possible.
Stuart Shanker
A developmental psychologist focused on self-regulation. He describes stress as cumulative and emphasizes that behaviour is an indicator of the load carried by the nervous system.