"There is a blanket assumption that knowledge and expertise are always good," Mehta says. "What we show is that it's not always true. Expertise is a double-edge sword."

There is no shortage of popular literature from various fields, including foreign affairs and business, about smart people making dumb mistakes. David Halberstam's "The Best and the Brightest" remains a primer on botched government decision-making by experts; namely, how key aides to Presidents John Kennedy and Lyndon Johnson, most of them products of an American academic and social elite, got us into the mess of the Vietnam War.

And, for sure, there is previous academic literature suggesting that experts can fall prey to false memories, and thus make false comparisons and inferences, precisely because of their greater-than-average memories of specific subjects.

Mehta and his business school colleagues expand on that literature via four related studies, each concluding that consumer products experts mistakenly, if inadvertently, tend to suggest apples-to-apples comparisons when such may simply not exist.

They open with a far less weighty matter than whether we should have escalated our involvement in Vietnam, namely what experts might erroneously tell you if you were wondering whether to get an Xbox 360 or a PlayStation 3. For sure, there are attributes of each product which are directly comparable, such as a 60 GB hard drive for the Xbox versus a 120 GB hard drive for the PlayStation. But there are many elements which describe just one of the products, such as the BluRay video playback of the PlayStation.



The core problem with an expert dissecting the differences, the researcher found, involves an impulse to "maximize comparability," or stretching to make comparisons and falsely recalling features that simply aren't there for one product. This consistent "false recall" was, they concluded, partly fueled by an expert's sense of accountability and resulting pressure to be, well, an expert.

Such an impulse was not found in non-experts and, interestingly, in experts when the researchers told them not to be worried about consequences as they answered a study's questionnaire. "When we told them they were off the hook, they made better decisions. Their false recall call rate went down!" said Mehta.

They tested their basic hypotheses in four experiments. For example, one examined if reducing an expert's sense of accountability for his judgments could "debias" them and improve their memories. Another inspected whether experts have a greater frequency of false recalls than novices when involved in memory-driven product comparisons.



"One reason for this tendency to provide more thorough and detailed information is that experts naturally feel a heightened sense of accountability for their judgments," the authors write. "It is this greater effort to compare individual features across options that, we believe, leads experts to commit more recall errors than novices."