Answer: Irreversability
Explanation: Irreversability concept is the trait shown by child at the stage of development which indicates that a child does not have potential to understand that any performed action can be undone to reach back to its actual form or stage.
Jake is also displaying the feature of reversibility because he is not able to consider that the hair cut is not permanent as the hair would grow back again after sometime , even though his father tried to make him understand it. He thinks haircut is a permanent action and cannot be reversed so he became sad.