What is the core of American values according to the author?

And now Carrie had attained that which in the beginning seemed life's object, or, at least, such fraction of it as human beings ever attain of their original desires … Applause there was and publicity 一 once far off, essential things, but now grown trivial and indifferent. Beauty also 一 her type of loveliness 一 and yet she was lonely. In her rocking-chair she sat, when not otherwise engaged — singing and dreaming.
What is the core of American values according to the author?
【正确答案】：

THE CORE OF AMERICAN VALUES IS MATERIALISTIC ACCORDING TO DREISER.

【题目解析】：作者认为，美国价值观的核心是唯物主义。