What does Mansfield's "The Doll's House" tells us about attitudes towards social class in the early twentieth century?

In Mansfield's "The Doll's House," the Burnell children are not allowed to associate with the Kelvey girls. The Burnell girls are members of the upper-class and a family friend (Mrs. Hay) has sent them a beautiful dollhouse. First the girls tell everyone at school about the house. Soon they are invited to invite girls over. However, the Kelvey girls cannot take part in anything associated with the toy for they are not only of a lower class, but they are also especially ostracized because their mother is washerwoman and it is believed that their father is in jail.

At the start of the story, the dollhouse is delivered, freshly painted, to the Burnell household. When it is unlatched, it swings open to reveal the beautifully wallpapered and decorated interior. There is a sense of openness and honesty as the narrator describes how amazing it is to watch the toy swing open. The narrator's description points to the story's main theme of class distinction as it describes how every house should be opened for all to see—much like a welcoming gesture:

Why don't all houses open like that? How much more exciting than peering through the slit of a door into a mean little hall with a hat-stand and two umbrellas! That is—isn't it?—what you long to know about a house when you put your hand on the knocker. Perhaps it is the way God opens houses at dead of night when He is taking a quiet turn with an angel…

While the Burnell girls are transported with joy in seeing such an amazing toy, it is part of a world that is closed off to the Kelvey girls because of their low station within society. The author seems to ask why there is such a distinction. Why cannot every home be open to the company of others, not restricted because of how much money a family makes or the work they do? The narrator notes that perhaps God sees a house wide open in this way as He enters with an angel in the deepest hours of the night. Certainly, if God does not recognize such a division, why should human beings?

Class distinction itself is not what Mansfield singularly struggles with as much as the heartlessness displayed by the upper-class toward the lower one.

The central theme in Katherine Mansfield’s story is the cruelty of class distinctions.

When Kezia, the younger of the Burnell girls, asks her mother if the Kelveys might come to see the house, her mother is very clear that this is unacceptable.

"Mother," said Kezia, "can't I ask the Kelveys just once?"
"Certainly not, Kezia."
"But why not?"
"Run away, Kezia; you know quite well why not."

The reader observes here that the separation of the classes is not something children are born knowing, but something they learn from their elders. This is clearly shown as the children meet Kezia Burnell one afternoon—and Kezia invites Lil and Else to see the dollhouse:

Lil gasped, then she said, "Your ma told our ma you wasn't to speak to us."

Kezia says it does not matter, but Lil refuses to enter the yard until Else, who hangs on her sister's skirt without a word, tugs at her sister's dress indicating that she wants to see the dollhouse.

Even in this situation, we note the difference between the sisters of the different households, perhaps also the result of class distinction. While Isabel is bossy and gets her own way with Kezia, Lil shows her love for Else and rather than insisting they leave, she gives in to her younger sister's unspoken request.

So Kezia draws the Kelvey children into the yard to see the magnificent dollhouse. Kezia throws it open to let her guests feast not only on the sight of the toy, but also to experience the inside of a grand house—something we can assume they have never seen. However, at that very moment Kezia's Aunt Beryl comes outside. She has had a horrible day, having received a nasty letter from a young man she knows that demands she meet him; he threatens to show up at her front door if she does not. This deeply alarms her. Ironically, it would seem that Aunt Beryl is subject to some social restrictions as well. The reader can infer that if Willie Brent shows up at the front door, this will spell disaster for Beryl. There must be something about him and his "terrifying and threatening letter" that will not be well received at the Burnell home, but the irony is lost on Beryl and she screams at the children to leave. It is extremely unsettling to note:

But now that she had frightened those little rats of Kelveys and given Kezia a good scolding, her heart felt lighter. That ghastly pressure was gone. She went back to the house humming.

There is, however, a positive note at the end of the story. Shamefaced and frightened, Lil and Else run away. Nearby, they sit down and Else speaks.

"I seen the little lamp," she said, softly.

Literally, Else sees the wonderful lamp that Kezia found so special. Her delight cannot be quenched by Aunt Beryl rampage. On the other hand (figuratively), Else has also been able to see something of a beautiful world hidden from her because of her reduced social standing: a light in a world that is otherwise very dark for her, her family and others like them.