What is the meaning of Le Therapeute by Magritte?

The two birds in the cage show that was our mind as a child free and full of imagination, but over time it meets more and more obstacles e.g. rules, personal interests, beliefs.

And that's what the bars are there for to show that so it means that the mind is prisoner because we give importance to rules beliefs and personal interests so the mind can't to what it likes were it could when you were a child