Follow The Eyes

It's sometimes known as the trigger, the kicker or the launching pad: the part of a package a shopper is looking at when he decides to flip the cereal box to read the back. The gesture is a strong indication that the sale has been clinched. Attempts to locate and understand that sweet spot have traditionally entailed guesswork. Now marketers are beginning to crack the mystery.

Devices that measure the direction of a person's gaze have dropped so far in price that the technology is now within reach of the most modest of marketing teams. By detecting the reflection of infrared light shone into an eye, video cameras mounted on the head of a test subject or on a computer gather data that allow software to chart a moving gaze. Two years ago San Francisco marketing firm Eyetools charged $30,000 per study. The fee is now $3,000, and revenue is up 50 percent over last year's.

InVivo Marketing in Paris fits test shoppers with goggles that transmit data wirelessly. It runs 15 mock supermarkets across Europe. CEO Eric Singler says gaze tracking for clients Procter & Gamble, L'Oréal and Nestlé has revealed much about the launching pad. Its purest manifestation is on cereal boxes. It is the fourth and final "message" scanned by the eye, following the image, the logo and the tagline. Rarely longer than five words, the spot is a blurb about vitamins, minerals or calories. If the front of the box presents more than four messages, such as additional photos, or more than 15 words, the launching pad may disappear. If the nutrition information is placed so it is viewed before the other messages, the sale may be lost. The launching pad must come last, freeing the shopper to flip the box to learn more. "Store shelves are very complicated," Singler says.

Michael Schiessl, managing director of Eye Square, a Berlin marketing firm, says eye-movement data can be displayed on easily-to-follow "heat maps." Numbered lines chart the scanning progression; color codes show how long eyes "fixate." Squiggly lines mean confusion (the images take too long to understand). Lines that shuttle back and forth between the same points indicate frustration (expected information can't be found). Dilated pupils are a sign of pleasure. Schiessl recently persuaded a sausage maker to put a cross-section photo on the label, and a baker to display bread on a wooden board—"a subliminal cue for tradition [and] natural products," he says. Sales shot up. Gaze-tracking is coming on strong.