Do you let brandnames dictate your product preference?

I just saw a show on TV where they tested this.
They had 4 cups, two of them where labelled with coca cola and pepsi, the other 2 where labelled with two no name brands.
All of the test subjects gave the brand name labelled cups higher scores than the no name labelled cups.
Here is the catch: The two no name cups were also filled with coca cola or pepsi.