“Researchers measure emotion with facial recognition that captures feelings like joy and sadness. Pair that with eyeball trackers and you can tell exactly what test subjects like or dislike. Some researchers use heart-rate monitors, skin-sweat sensors and even brain-wave detectors to measure reactions. Airlines use biometric research to plan menus and pick cabin colors. Amtrak has been using it to design new railcars. Online travel agencies like Expedia test every aspect of desktop and phone screens, looking for pain points during shopping that may frustrate buyers, as well as for colors, layouts and elements like photos that lead to increased booking.”

Source : Your Next Vacation Is Written on Your Face – WSJ