In the movie The Heiress, directed by William Wyler in 1949 and based on Henry James's 1880 Washington Square, Catherine, as presented by Olivia de Havilland, portrayed two completely different characters. In the beginning she portrayed a very meek and timid young girl. The character was portrayed this way by using a weak and faint voice. When Catherine spoke it was always faint and lacked confidence. Even when she was excited about showing her father (Ralph Richardson) the fish that she had bought for him, she still spoke quietly and used a reserved voice. However, by the end, her deeper voice revealed the confidence she had developed due to what she had undergone.
Dr. Sloper played a huge role in the characteristics of Catherine. He was always quick to degrade her. Even when she wore a beautiful gown, he would point out that she was not as beautiful as her mother. He had the knack for bringing someone down even if the criticism was not necessary. It was as though he resented Catherine because she was the reason why his beloved wife was no longer with him. Dr. Sloper gave Catherine all of the worldly goods one could ask for, but he never gave her love.
He went as far to make Catherine feel that no one person could love her because she was not beautiful, smart or composed as a lady should be. Dr. Sloper even went as far to ask her if she really thought someone as good looking as Morris (Montgomery Clift) could fall in love with someone like herself. Since he could not love Catherine, then naturally no other person would be able to love her.
Catherine acknowledged to her Aunt Lavinia (Miriam Hopkins) that no one had ever loved her when Morris did not come to elope with her. It was at this point in the movie her personality changed completely. When Catherine spoke with a deeper voice than hitherto, she tended to carry herself with an air of confidence. It was as though she had become her father. She now composed herself in a manner that was similar to his. In the end Catherine became the person that had despised her the most.