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How to change behaviour

Viewing time: 10 min

This section explains how behaviours can be changed. Different assessment methods that can be used to find the reasons why behaviours occur are described. How to carry out a simple analysis of behaviour using an ABC chart is demonstrated.


How can Behaviour be Changed?

Knowing why an inappropriate behaviour occurs, allows us to predict and prevent that behaviour from being repeated. An intervention can be implemented which can teach skills that promote positive behaviour and reduce negative behaviour.

Function (why) Vs Topography (what)
The topography of a behaviour describes what behaviour is occurring but it says nothing about why the behaviour occurs.

This is where the function of the behaviour is needed so we can understand why it is happening and then decide what intervention needs to be applied.

For example: when a child deliberately hurts themselves we call this ‘self-injurious’ behaviour. We are describing the topography of the behaviour as ‘self-injurious’ however this does not tell us why the behaviour is happening

Function of Behaviour

Sometimes the behaviour is linked to an event which occurs immediately before the behaviour (antecedent) and other times it is linked to an event which occurs after the behaviour which causes the behaviour to re-occur (consequence)

Functional Assessment Methods
There are three specific functional assessment methods:

(a) Functional Analysis

(b) Informant Methods

(c) Direct Observation

Functional Analysis

Functional Analysis is probably the most accurate, and controlled method of conducting a functional assessment. Involves experienced practitioners deliberately changing what happens before and/or after the behaviour in an effort to understand what might be causing the behaviour. Conducting a functional analysis requires a high level of expertise to be done effectively.

However, although not as accurate other functional assessment methods. The Direct Observation approach along with the Informant Method is probably the best way for parents and teachers to try and understand why a child is engaging in problem behaviour. A questionnaire along with an ABC chart can help to identify and define the problem behaviour.  Knowing why the behaviour is occurring allows the parent/teacher to implement an intervention that will not only reduce or eliminate the problem behaviour but also teach new skills that will prevent the behaviour from re-occurring.

Informant Method

It is often helpful to begin assessing behaviour by

Conduct interviews with the people most involved in the child’s life. Parents, teachers, caregivers or others who work closely with or spend time with the child can give a valuable insight into why the behaviour may be occurring. The interview can help to prepare the assessor to conduct direct observations by identifying and defining the problem behaviour that is being targeted, identify potential triggers (antecedents) and consequences that may be causing the behaviour to occur. It will also help to provide an overall understanding of the problem behaviour and allow insight into difficulties and strengths that the child might have.

Direct Observation

Direct observation is where the observer (parent/teacher) monitors the child and records what happens just before and just after the behaviour. Based on the information gathered, a theory as to the function of the behaviour is developed. This can be done using an ABC chart.


ABC stands for Antecedent, Behaviour, Consequence. It is a behaviour modifying strategy often used for children with autism. It is a scientifically based method which reduces or eliminates undesired behaviour and promotes positive behaviour. To understand ABC it is important to look at what the three terms mean.


The Antecedent refers to the action or event that occurred before the behaviour.  They are things that contribute to or cause the behaviour to happen. It may be a request from a parent or teacher or the removal of a toy, the list is endless.

When looking at antecedents it is also important to look at Setting Events. These are events that happen before the antecedent for the behaviour.  They are not the cause of the behaviour but they make it more likely to happen. Illness, lack of sleep, crowds of people, noisy places and too much instruction are just some examples of setting events.

When Identifying Antecedents consider these Questions

Where did the behaviour occur?

With whom?


What activity?

Is the child tired, hungry, thirsty?

Is it too hot or too cold?

What is the noise level?

What were the other children or adults doing?

Behaviour refers to what the child does that causes concern. It is also known as the target behaviour that we want to reduce in:

Frequency (how often it occurs)
Intensity ( how severe it is)

Target Behaviours
The target behaviour is the behaviour that needs to be changed or eliminated. It is a problem behaviour that can cause a danger to the child or others such as physical aggression, or a behaviour that interferes with learning such as repeatedly disrupting.


Consequences are what happen directly after the behaviour has occurred.

Consequences can serve to either increase or reduce the likelihood of the behaviour occurring again.

When a parent gives in to the demands of a crying child, the behaviour is the crying and the consequence is the child getting what he wants.  The consequence (getting what he wants) is likely to increase the likelihood of the behaviour (crying) occurring again in the future. This is because crying to get what he wants works for the child.

Alternatively if a child climbs (behaviour) and falls and gets hurt (consequence) the child is less likely to climb (behaviour) again.

ABC Chart
An ABC Chart is a method used to analyse why a behaviour is occurring (function). It allows us to predict the occurrence of the behaviour and to understand what intervention is needed.

Author: Alma Carroll - Behavioural Specialist
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