How are the younger Birlings (Sheila and Eric) different to their parents in the play?

Eric and Sheila learn a lesson from the Inspector's visit. They come to realize that they do have a responsibility to the people that move in and out of their lives.... even people they never officially meet. The Birling parents, however, immediately feel themselves off the hook and congratulate each other when they learn no one has been brought into the infirmary..... they haven't learned anything, they're merely relieved.