Gevins says that he has no way of evaluating the Emsense technology because there is no technical information on their website about what they are actually doing or any data or references to peer-reviewed research they've published using their technology. But he notes that Emsense isn't the first company that has tried to use EEG sensors to track people's emotional responses to advertisements. "There have been a number of start-ups that have made EEG headsets of unknown quality and tried to market devices or studies for evaluating advertising and other analogous uses," Gevins says. "They have a lot of press releases, but ultimately they fail ... The bottom line is, they couldn't do it." For example, in the 1990s, a company called Capita Research tried to use EEG technology licensed from NASA for marketing purposes. Gevins, who has been working on correlating EEG to attention and memory for decades, says that he's skeptical of companies that lack scientific depth in this area. "If someone has the capability of actually doing this," he says, "then there would be objective indicators that it's real, for instance publications that have gone through peer-review."
Even so, Emsense, which was founded by a handful of MIT graduates, claims that its technology is superior to that which has come before it. While it hasn't published in peer-reviewed journals, it has 22 patents that cover topics that range from sensing using a dry EEG sensor to processing the data and analyzing it for its customers, says Lee. And he claims that customers, such as video-game maker THQ, creator of Frontlines, are coming back.
Emsense contacts potential testers in its database of about 5,000 people. These testers go to Emsense testing centers, scattered throughout the country, where they put on the headset and sit down to watch television or play a game. Lee explains that from the headset's data, the company's algorithms deduce a handful of coarse assessments about a tester's experience: when she has positive or negative feelings, whether or not she is concentrating, if she is excited, and, for games, how much she is engaged with it. Emsense then produces charts that qualitatively show these responses throughout the experience.
For instance, in a commercial for a detergent, an advertiser shows a pregnant woman, who is wearing a pink shirt, eating ice cream. A few seconds into the ad, she drops ice cream on her shirt, scoops it up with her spoon, and continues to eat. Toward the end of the commercial, the product is introduced, and the stain removed. According to Emsense's data, women tend to respond negatively to the first part of the ad, apparently growing distressed as the woman drops the ice cream and scoops it up. When the product name is introduced and the stain removed, women's responses turn more positive. Men, however, respond positively when the woman drops ice cream, but they remain neutral throughout the rest of the commercial. This is evidence, says Lee, that the commercial works well with its intended audience--namely, women.
But positive emotions, in particular, are difficult to measure using EEG, says Brian Knutson, professor of neuroscience at Stanford University. His group uses functional magnetic resonance imaging to peer deep within the brain, where the electrical signals that correspond positively are strong, he says. But by the time they make their way to the scalp to be measured by EEG, the signals are much weaker, and it's difficult to get a clean reading. But ultimately, Knutson says, the important question to ask is whether or not Emsense's approach is better than self-reporting, which is "a hell of a lot cheaper."