the monkey's paw was created to teach. Note the response of Mr. White to the $200 he is given as compensation for his son's death:

Unconscious of his wife's shriek, the old man smiled faintly, put out his hands like a sightless man, and dropped, a senseless heap, to the floor.

Clearly, this strongly suggests that Mr. White has learned that "fate ruled people's lives, and that those who interfered with it did so to their sorrow." This is supported by the way in which he uses the final wish to cancel the second. His wife, on the other hand, clearly has not learnt this lesson, as her determination to get her husband to use the monkey's paw to restore their son to them shows.

All three family members initially demonstrate curiosity about this magical talisman from a distant land. Mr. White has to talk Morris into telling the story behind the paw, and "his three listeners leaned forward eagerly." When Morris pulls the paw out of his pocket, Mrs. White instinctively "drew back with a grimace," but her husband and son inspected it curiously. After hearing about the curse, both Mr. and Mrs. White ply Morris with questions aimed at revealing whether there were still any wishes left. 

When Mr. White rescues the paw from the fire, Morris gives him an ominous warning: "I warn you of the consequences."

As the group sits down to dinner, the mood lightens a bit, and when Mr. White starts to wish an extra pair of hands for his wife, "all three burst into laughter."

All three members of the White family are setting themselves up for the same fate as the cat curiosity killed. Mrs. White should have heeded her initial gut reaction when she first laid eyes on the paw, but curiosity prods her and her family to ignore their guest's warning. 

Sergeant Major Morris tells his curious audience the following about the paw:

"It had a spell put on it by an old fakir, a very holy man. He wanted to show that fate ruled people's lives, and that those who interfered with it did so to their sorrow. He put a spell on it so that three separate men could each have three wishes from it."

The Sergeant-Major told the story with such conviction that all three the Whites realised that their slightly jovial attitude was out of place for the issue was a serious one.

Herbert was the first to respond and he thought that he was being quite clever by asking Morris why he did not make three wishes himself. He clearly does not take the story seriously and continues to mock the entire idea of the paw having such supernaural properties. He later emphasises his cynicism by saying:

If the tale about the monkey's paw is not more truthful than those he has been telling us, ... we sha'nt make much out of it.

and

Why, we're going to be rich, and famous and happy. Wish to be an emperor, father, to begin with; then you can't be henpecked.

He also tells his father:

If you only cleared the house, you'd be quite happy, wouldn't you?. ...Well, wish for two hundred pounds, then; that 'll just do it.

Herbert takes his mother's lead and his cynicism is pertinent. Ironically, it is this suggestion which results in the gruesome sequence of events later.

Mrs White is quite intrigued at first and repeatedly asks the Sergeant-Major questions about the paw and what he did with it. She obviously wants to know more. Later, she however adopts a flippant attitude and makes fun. She says:

Sounds like the Arabian Nights, ... Don't you think you might wish for four pairs of hands for me?

She is suggesting that the entire tale sounds like a Middle-Eastern fairy-tale and therefore cannot be true. Her suggestion about wishing for four pairs of hands is an explicit declaration of her disbelief. 

Mr White comes across as the one most profoundly affected by Sergeant-Major Morris' supernatural tale. He at no point makes fun of the paw's supposed powers. The depth of his intrigue and interest is indicated when he grabs the paw out of the coals in the fireplace when the Sergeant-Major throws it into the fire in order to destroy it. He is also the one who asks the most insightful questions, such as:

If you've had your three wishes, it's no good to you now, then, Morris, ... What do you keep it for?

and

If you could have another three wishes," said the old man, eyeing him keenly, "would you have them?

Mr White seems to have believed most of what the Sergeant-Major said and he appears determined to put the paw to the test, in spite of Morris' warning. He actually does make a wish. At Herbert's suggestion, he wishes for two hundred pounds to clear his bond, even though he expresses some doubt. This wish is to become horribly true later. 

Mrs. White withdraws from the paw at first, not wishing to touch it.  Later that evening, she treats the subject lightly, joking that her husband might wish for an extra pair of arms.  Her levity reveals that she does not fully believe in the paw's power.

Mr. White is amazed by the story and potential of the paw.  In fact, when Morris throws the paw onto the fire, White wants it so bad that he snatches it off the fire.  He truly believes in the paw's magic.

Herbert-- Incredulous, but intrigued, Herbert's reaction is at first joking--to wish to be an emperor-- but then a practical one, advising his father to wish for two hundred pounds. 

I would also say that when the family first hears the story of the monkey's paw, their curiosity is really about hearing a tale of magic and intrigue, almost like one who sits around a campfire and awaits a scary story, just for the thrill of it. After all, Mr. White complains early in the story about living so far out in the country that no one really stops by, especially on a night such as Jacobs describes, with its wind and rain. Truly, Jacobs sets the scene to be a scary story with the dismal opening.

When the Whites first see the monkey's paw, Mrs. White "drew back with a grimace, but her son, taking it, examined it curiously." Mr. White also takes the paw and examines it, though no descriptors are given about his reaction.

Once the family is in possession of the "talisman," they still treat the monkey's paw as if it is a joke, but when Mr. White makes his first wish, "a fine crash from the piano greeted his words, interrupted by a shuddering cry" from Mr. White, which frightens Mrs. White and Herbert. Mr. White claims that the paw moved when he wished, which causes the family to doubt their initial mirth at the story the soldier told. In the morning, however, they return to their disbelief.

By the end, when the wish of 200 pounds is granted in lieu of Herbert's death, and then the second wish seems to bring Herbert back to life, Mr. and Mrs. White both believe in the power of the paw, so much so that Mr. White uses his last wish to wish that Herbert returns to the dead.

When Mr. White learns about the monkey's paw and its ability to grant three wishes to three people, he is very intrigued. He does not feel afraid, even though Sergeant Major Morris advises him to throw it away. The Whites, after they make their first wish, think that the monkey's paw does not really have any power. Even though they were told that the first owner's last wish was for death.

Sergeant Major Morris does not tell us what he wished for, but he tries to dispose of the monkey's paw by throwing it in the fire. Mr. White rescues it.

Once he has properly paid Sergeant Major Morris a small amount for the monkey's paw, he wishes for 200 pounds, English money.

His first wish is granted through the loss of his son, Herbert. A stranger calls on the Whites to inform them that Herbert was killed in an accident at the factory, he fell into a machine. For their loss, they are given a check of compensation for the sum of $200 pounds.