Finding the function of the behaviour is an important step in being able to effectively support the student. Often this can be done simply by talking to the student. However if the student does not want to talk, or the talk does not give you helpful information you will need to try other strategies. You could achieve this through observation or conduct a Functional Behaviour Assessment (FBA).
FBA is a systematic approach that helps identify and understand the following aspects of behaviour:
Form: the observable behaviour – what are they actually doing?
Function: the underlying cause – what is the goal of the behaviour?
Context: the setting – where does it occur? What happens immediately before and after?
More information on this can be found here.
Resources
ABC Checklist
ABC Data Sheet