Hitting activates the largest upper body motor group — the arm, shoulder, and hand complex. It requires minimal motor planning and produces immediate consequences: the person reacts (attention), the demand stops (escape), or the frustration discharges (sensory release). Low effort + high effectiveness = the brain's default aggressive response.

Biting provides massive jaw proprioceptive input (TMJ activation) and is an extremely effective aggressive behaviour — producing immediate, intense pain and an immediate caregiver reaction. It carries dual reinforcement: sensory (intense oral proprioception) and social (demand removed or attention gained). Both functions must be addressed or the behaviour persists.

Kicking recruits large lower-extremity muscles — quadriceps, hip flexors — producing significant force and intense proprioceptive discharge. Critically, the child may not even be aiming. The legs flail as part of full-body dysregulation. Anyone in range gets hit not out of intent but out of proximity to an overwhelmed nervous system.

Scratching is a fast motor response requiring minimal planning. It frequently occurs during close physical proximity — caregiving tasks — where the child is already sensory-overloaded by unwanted touch. The scratch may be escape from tactile input as much as aggressive expression. Understanding this distinction changes the entire intervention approach.

Pushing is often both proprioceptive and escape-motivated simultaneously. The child needs deep pressure input (arms extended against another body) AND distance from an overwhelming stimulus. The push delivers both in a single action — which is why it works so effectively and is so highly reinforced by the environment.

Targeted throwing requires object identification, motor planning, arm execution, and visual tracking — more complex than hitting. When directed at specific people, the behaviour has been shaped by reinforcement history: throwing at this person produces the desired outcome most reliably. The target reveals the function.

Sibling aggression is almost always multi-function: tangible (the sibling has what they want), attention (parent intervenes, delivering attention), escape (sibling is in their space), and sensory (sibling interaction is unpredictable and overwhelming). Constant proximity creates continuous trigger exposure with no natural breaks.

School is the highest-demand, lowest-control environment in a child's life. Aggression at school typically reflects escape from academic or social demands, sensory overload in the classroom, frustration with tasks beyond the child's current ability, or social conflict with peers. The school environment itself creates the conditions — which means the school must be part of the solution.

Threatening posture equals sympathetic activation with partial PFC inhibition. The body is prepared for aggression — heart rate elevated, muscles tensed, adrenaline flowing — but the action hasn't fired. The brake is on but slipping. De-escalation at this stage prevents the aggressive motor response from executing. This is the most valuable intervention window in the entire aggression sequence.

"Safe hands" builds a stored motor programme in the basal ganglia for appropriate hand use. Through consistent practice and reinforcement during calm states, "safe hands" becomes the default motor pattern — gradually replacing the aggressive pattern. The more the safe pattern is practised and reinforced, the more automatic it becomes. Repetition during calm is the investment that pays off during dysregulation.

Sensory overload (noise, light, touch, smell, crowd). Demand presentation (non-preferred tasks, transitions, unexpected changes). Communication failure (not understood, not heard, unable to express). Pain or illness (ear infection, GI distress, headache — often undetected). Hunger, fatigue, or sleep disruption. Social proximity (too close, too long, too unpredictable).

Caregiver exhaustion → inconsistent responses → child learns aggression is unpredictably reinforced → aggression increases → caregiver exhaustion deepens. This cycle is self-reinforcing and clinically recognised. Breaking it requires addressing caregiver wellbeing as a clinical priority — not an afterthought. Secondary traumatic stress in parents of children with severe aggression is documented at rates comparable to frontline healthcare workers.

Medication is considered when: aggression is severe and causing injury, behavioural interventions have been implemented consistently without sufficient reduction, there is evidence of underlying anxiety, mood dysregulation, or ADHD driving the aggression, or the child's quality of life is significantly impaired. In India, risperidone and aripiprazole are the two FDA/CDSCO-recognised medications for irritability and aggression in ASD. Both require careful monitoring.

Escape: "Get this demand away from me." The most common function — aggression terminates the non-preferred task or interaction. Attention: "Look at me." Aggression produces immediate caregiver response. Tangible: "Give me that." Aggression obtains a preferred item or activity. Sensory/Automatic: "This feels good or releases something." The behaviour is internally reinforced — no social consequence needed. Most children have mixed functions. FBA identifies the primary driver.

1. Operational definition: Exactly what counts as the target behaviour — precise enough that any observer would agree. 2. Antecedent strategies: What changes before the behaviour to reduce triggers. 3. Replacement behaviour: The function-matched alternative the child will be taught. 4. Consequence strategies: How every person in every environment responds — consistently. 5. Crisis plan: What happens when aggression occurs despite prevention — safety hierarchy, post-crisis protocol.

Frequency: How many times per day/week does the behaviour occur? The most basic and most useful metric. Duration: How long does each episode last? Relevant for sustained behaviours like hair pulling or property destruction. Intensity: A simple 1–3 scale (mild/moderate/severe) captures whether episodes are getting worse even if frequency is stable. Time of day / setting: Patterns reveal triggers. Most families discover that 80% of aggression occurs in 2–3 predictable windows. Antecedent: What happened immediately before? The most clinically valuable data point.