An excerpt from Mindhacks:

Edge has a video interview with two of its creators, psychologists Mahzarin Banaji and Anthony Greenwald, and an online version of the IAT which allows you to test your unconscious associations in relation to the US presidential candidates.

The IAT is a computer task that measures the strength of automatic, implicit or unconscious associations between concepts.

Let’s say we’re interested in whether black or white faces are more linked to positive or negative associations.

Faces of black or white people, and either pleasant or unpleasant words are flashed up on screen, one at a time. Participants are asked to press one key if the face is black or the word is pleasant, and other if the face is white or the word is unpleasant.

In other words, you’re asked to classify both black faces and pleasant words using the same response, and white faces and unpleasant words using the same response.

Next, you’re asked to do the same thing, but with the reverse associations: so you’re asked to classify black faces and unpleasant words together, and white faces and pleasant words together.

The idea is that you’re going to be quicker doing whichever classification best matches associations you already have.

So, if you already have unconscious associations between white and pleasant, and black and unpleasant, you’re going to be quicker when these two responses are grouped.

Importantly, the idea is that these associations are different from our conscious attitudes. Someone who is definitely not racist might still have negative associations with black people, perhaps because of exposure to social stereotypes.

Most studies have more than just the two conditions, to control for order, practice and other effects and if you’re interested, you can take part in this exact experiment online.

It was originally thought that the test could uncover people’s implicit or hidden attitudes (indeed, it was originally called the Implicit Attitude Test) but it’s now generally thought of just in terms of associations, because, in effect, it measures how closely two things are linked, and implicit attitude sounds more like a sort of evaluation or stance on something.

The value in this sort of test is not only in that it can pick out associations we might have but don’t admit to or aren’t aware of, but it can also map out how various things influence the unconscious structure of meanings in the mind and brain.

Needless to say, it’s been researched intensively since it was first uncovered, with research suggesting it can even pick up on hidden violent associations in psychopathic murderers.

Link to video interview and presidential IAT at Edge.
Link to previous WashPost article on the IAT.