Give a detailed explanation of how Scrooge's attitude changed after the three spirits visited him.

We can see the extent of Scrooge's transformation by comparing his attitude in Stave One, before the visits, with his attitude at the end of the story, in Stave Five.

First of all, Scrooge rediscovers his family and friends. Before the ghosts visited him, for example, Scrooge shunned society to the point that few people cared about him, as the narrator comments:

No beggars implored him to bestow a trifle, no children asked him what...

We can see the extent of Scrooge's transformation by comparing his attitude in Stave One, before the visits, with his attitude at the end of the story, in Stave Five.

First of all, Scrooge rediscovers his family and friends. Before the ghosts visited him, for example, Scrooge shunned society to the point that few people cared about him, as the narrator comments:

No beggars implored him to bestow a trifle, no children asked him what it was o'clock, no man or woman ever once in all his life inquired the way to such and such a place, of Scrooge.

But, by Stave Five, Scrooge's attitude has undergone a great change and he actively seeks the company of others:

He...watched the people hurrying to and fro, and patted children on the head, and questioned beggars, and looked down into the kitchens of houses, and up to the windows: and found that everything could yield him pleasure. 

Secondly, Scrooge's attitude changes in a way that enables him to understand the importance of charity and he willingly donates his money to the poor. As we saw in Stave One, for instance, Scrooge turned away the charitable collectors. But, in Stave Five, he makes a generous donation to the same fund and, in fact, invites the gentleman to come and see him again.

Finally, Scrooge comes to appreciate the importance of Christmas. His attitude of "bah, humbug" has been replaced by a genuine love of the season. We see this in his purchase of the prize-winning turkey, his visit to Church and his decision to dine with his nephew, Fred. Compare this with the Scrooge from Stave One and we see just how much his attitude has changed: he was reluctant, for example, to give Bob the day off and told his nephew to leave him alone. 

Scrooge really has changed and, more importantly, this change is long-lasting: 

Scrooge was better than his word. He did it all, and infinitely more.