She is the only member of the Birling family to almost completely resist the Inspector's attempts to make her realise her responsibilities. This demonstrates her inability to change attitudes after a lifetime of high living and is representative of the upper classes being closed-minded and ignorant of the plights of others. Sybil responds in a cagey manner to questioning, unwilling to see how she had any part in the suicide of Eva Smith – despite her being the young woman's very last resort. An example of the attitude she displays towards the Inspector is when she tells him that “if you [the Inspector] think you can bring any pressure to bear upon me, you're quite mistaken”, denying that she has anything to feel guilty about – and continuing the claim that she is uninvolved in Eva's plight.
In the same way as her husband, her high social standing gives her an inflated, and incorrect sense of her own opinions. When the Inspector details the fact that Eva was pregnant with the baby of a man who abandoned her, Sybil blames “the drunken young idler”, “who was the father of the child she was going to have”. However, the person she is describing in such derogatory terms turns out to be her own son. This highlights the double-standards of the upper classes, as she attempts to retract the remarks when the father of Eva's child is revealed.
Though Mrs Birling does indicate sympathy at the tragic fate of Eva Smith, her insistence that she is not responsible for it in any manner and the prejudice displayed in the girl's charity plea shows that the death does not have anywhere near as much impact as it does on the younger members of the family. When the Inspector leaves the household, and doubt is brought up about Goole being a legitimate policeman, she joins in with her husband and Gerald in passing off the Inspector's case as a joke, and claims that “in the morning they [Eric & Shelia] will be as amused as we are”. This shows that she learnt nothing from the events of the night, and is willing to act as if all of the revelations brought forward about the actions of her family by Inspector Goole are completely irrelevant.
The depiction of Sybil is one of an upper class woman who has married a middle class male with significant financial backing to maintain her privileged lifestyle. Priestley creates this character to display the overwhelming importance of class & wealth to people of high social standing – her marriage to Arthur is a prime example of this. Sybil appears out of touch with reality - a common criticism of the upper classes - as she claims “I can't believe it – I won't believe it” when she finds out that Eric is the father of Eva's baby. Sybil, like her husband, treats the younger members of the Birling family as children, telling them to calm down numerous times during the Inspector's questioning, and calling Sheila “childish” when she claims that Inspector Goole has taught the family a lesson. Mrs Birling is even more uncooperative with the Inspector than her husband, and does not see her actions in dealing with Eva at the charity as significant whatsoever, despite knowing the girls final fate.
Sybil is a woman who has spent her whole life in luxury, and Priestley uses this fact as a way of showing that those who spend the longest at the top of the social scale are the most morally corrupt.
