Given the demise of the Bradley Effect in this election, it's interesting to speculate on how we came to believe it would occur. Here's a view in the Science section of the NYT:
http://www.nytimes.com/...
And a debate in the psychology literature on unconscious racism measures:
http://tierneylab.blogs.nytimes.com/...
Context seems to be needed (my fault): The IAT was used to justify under-polling of Black candidates, with designers of the test pushing that point.
http://tierneylab.blogs.nytimes.com/...
http://newsagency.thecheers.org/...
http://www.pbs.org/...
http://discussionleader.hbsp.com/...