The fourth season concludes with Arthur visiting a psychiatrist and recalling via flashback a disturbing encounter with his dad (Ben Stiller) that may explain Arthur's abrasive personality. Carrie and Doug decide to 'validate' Arthur in everything he does. This leads to Carrie visiting the psychiatrist, who also has a flashback that makes her doubt her personality. Which leads Doug to also visit the psychiatrist and has his own flashback that makes him learn something about himself.