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Archive for January 6th, 2008

Tony Greenwald on the IAT

Posted by The Situationist Staff on January 6, 2008

Jesse Erwin has an article in December’s Observer summarizing a recent talk given by Tony Greenwald, one of the creators of IAT (and frequent collaborator with Situationist contributors, Mahzarin Banaji and Brian Nosek), about how and when the implicit association test works. We’ve excerpted portions of Erwin’s article below.

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“Left…right…left…right” could be heard echoing from the Hilton Washington’s Military Room during the APS 19th Annual Convention. And although the chorus may have sounded like boot camp exercises to curious passers-by, it was merely APS Fellow Anthony Greenwald, professor of psychology at the University of Washington and recipient of the Society of Experimental Social Psychology’s 2006 Distinguished Scientist Award, administering the Implicit Association Test (IAT) en masse during his Psi Chi Distinguished Speakers address. Throughout his talk, the University of Washington Professor educated his audience about the history and validity of the IAT and, of course, provided the opportunity to experience the IAT firsthand.

“So what is the IAT?” Greenwald asks his audience. “It’s a measure of associative knowledge. And I don’t describe it as a measure of prejudice or bias, although it can be used to measure implicit prejudice or bias.”

The IAT has risen to prominence since Greenwald first published his findings in 1998; the Brief IAT of race has been taken over a million times. On the surface, the IAT asks participants to categorize words or images on a computer screen with a touch of the keyboard. These categorizations begin to require some cognitive gymnastics, however, as categories become combined. The time it takes to sort out stimuli from the combined categories provides some insight into participants’ mental associations.

“How does it work? Well, fairly simply. If two concepts are associated, it is easy to give the same response to exemplars of both,” says Greenwald. That’s a deceptively uncomplicated explanation behind one of contemporary psychology’s most influential research paradigms. “There’s little more theory underlying the IAT than the idea of association between concepts.”

But the provocative implications of the IAT have sparked controversy in both research circles and the mainstream media. So in his address, “Assessing the Validity of Implicit Association Test Measures,” Greenwald came to the IAT’s defense and discussed its psychometric worthiness.

When discussing internal validity, for example, Greenwald says “empirical research demonstrated that there are several things that might get in the way that in fact did not.” Things like participants’ familiarity with the items or lack thereof, which side of the screen categories are presented on, or whether the person is right or left handed have all been mentioned as possible confounds, but haven’t been borne out in research.

Greenwald went on to illustrate the convergent validity of the IAT with self-report using an example from the 2004 presidential election. Implicit attitudes toward each candidate correlated .73 with self-report measures. “That’s quite high,” Greenwald says. “And that’s evidence of convergence.”

Conversely, research on IAT measures of age attitudes have demonstrated evidence of discriminant validity with self report. Greenwald offers this explanation for the dichotomous results: “I think you get convergent validity when both implicit and explicit attitudes are shaped by the same influences, which means they are formed relatively late in life, such as political preferences.” For those attitudes that are formed earlier in life — in particular racial/ethnic, young/old, and male/female stereotypes — IAT results are likely to diverge from the explicit self report measures.

In a time where social desirability confounds are of pervasive concern in psychological research, one of the IAT’s greatest merits appears to be resistance to faking. Studies have demonstrated that participants rarely devise a successful faking strategy. It appears that taking one’s time is the easiest way to doctor results. “It does work,” Greenwald says of the strategy, “but it also tends to be detectable statistically.”

But as with any test, the IAT has its psychometric vulnerabilities. Greenwald describes the elasticity of the IAT, where experiences with exemplars of test categories shortly before the test can alter results. So, according to Greenwald, having a friendly interaction with a black experimenter just before the test will likely dampen evidence of bias.

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“The last topic is the most interesting one,” Greenwald asserts. “Does the IAT predict anything interesting?” Pointing to a meta-analysis being conducted by Yale University graduate students Andy Poehlman and Eric Uhlmann, Greenwald says that the IAT performs better than self report at predicting behavior. “This IAT has incremental predictive validity relative to self-report. [The results are] statistically significant, and very clearly so in the meta-analysis.”

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To read the entire article, click here. To visit the Project Implicit website and find out more about implicit associations, click here. For a list of Situationist posts on implicit associations and attitudes, click here.

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