Hi,
Good thinking here - students often struggle with differentiating these concepts. Here's my stab at answering your question:
- Extinction: the performance of a learned behaviour/response ceases when the reinforces is no longer presented. Essentially, the association is lost.
- Habituation: the reaction to a natural response is no longer observed.
The difference is between whether this was a learned behaviour or a natural one.
Hope this helps :)