By Melissa Healy, Los Angeles Times

To predict a large population’s likely response to something — a product, politician, or policy — political consultants, marketing gurus, and advertising execs have long favored the focus group. Ask a small segment of the target audience what it thinks about something, the formula goes. Tweak accordingly, and unleash on the public.

But what if a handful of subjects, a dozen or so electroencephalograms, and a few hundred yards of electrical wiring could do a better job of identifying a potential hit (or winnowing out a rotten egg)? A new study finds that listening to the average brain wave activity of a small group of subjects produces a more accurate prediction of a large population’s likely embrace of something than does asking the same few subjects what they think.

In the latest research, the 2010 series premiere of the AMC show “The Walking Dead” (shown after its airing to youthful subjects who’d not seen it) provided the experimental stimulus. The larger public’s actual judgment on the show’s curtain-raiser was gleaned not only by its Nielsen ratings but by a minute-to-minute tally of Twitter postings during the broadcast making reference to the show and its contents.

The researchers who conducted the study at New York University’s department of biomedical engineering then explored whether the collective brain activity patterns of a small group of subjects would predict a larger population’s responses to Super Bowl advertisements from 2012 and 2013. Their report was published this week in the journal Nature Communications.

Asking subjects’ opinions was of little value in predicting a hit or a flop. In addition to measuring their brain activity and devising a single measure of inter-subject synchrony, researchers asked subjects to rate the appeal of, or their level of engagement in, these televised offerings. The averaged ratings that subjects gave were a poor prediction of whether the viewing nation would stay engaged in and remember “The Walking Dead” or the Super Bowl ads.

In fact, the answers that subjects gave often didn’t fit with the collective brain wave patterns researchers observed and measured. In the case of some Super Bowl ads, the subjects’ oral assessments suggested they were left cold by the televised stimulus they had just seen, while an average measure of their brain wave patterns showed they had watched with keen interest. In other cases, subjects reported high engagement, on average, with an ad they were seeing. But the collective measure of their brain activation patterns suggested they were unmoved by the content.

It turns out that people in focus groups — and those in one-on-one interviews with evaluators — lie. Or they temper, hedge, prevaricate, or offer an opinion they think will make them look good to the person asking, said the study’s lead author, Jacek P. Dmochowski, now a research associate in Stanford University’s department of psychology. This “cognitive filtering” makes their assessments — even when they’re averaged — suspect, said Dmochowski, whose research was conducted under the supervision of senior author Lucas C. Parra of NYU.

Brain waves, by contrast, do none of those things, suggested Dmochowski. Subjects’ scalps were rigged with electrodes, allowing researchers to measure the minute-to-minute intensity of their brain activity. When alone in a room watching the series premiere of “The Walking Dead,” their patterns of brain activity suggested either that they were drawn into the drama or that their attention had wandered off to other pursuits.

When a large bloc of people pass collective judgment on, say, a new TV show, there is also no lying, no hedging and no tactful consideration: from the comfort of their couches, with remote-controls in hand and other activities competing for their time and attention, the collective of individuals that make up the public jury decide whether a show will be a hit or not, just as they decide whether a public initiative will be embraced or a politician will rally support.

When there was strong synchrony in the brain activity patterns of a small group — as few as 12 subjects watching “The Walking Dead,” for instance — the researchers believed they had distilled the signal that marks the stimulus as a hit. When brain activation patterns varied widely across the small group of individuals — as was seen with some Super Bowl ads that did not fare well in national surveys — researchers discerned the failure signal.

“The stimuli which we judge favorably may be those to which our brains respond in a stereotypical manner that is shared by our peers,” the researchers wrote. “Viewed in another manner, if one is able to evoke reliable neural activity from one’s audience, then that audience is, as a whole, more likely to find one’s message favorable.”

AFP Photo

Interested in national news? Sign up for our daily email newsletter!