Eye tracking devices sound a lot more like expensive pieces of scientific research equipment than joysticks – yet if the latest announcements about the Assassin’s Creed game are anything to go by, eye tracking will become a commonplace feature of how we interact with computers, and games.
Eye trackers provide computers with a user’s gaze position in real time by tracking the position of their pupil. The trackers can either be worn directly on the user’s face, like glasses, or placed in front of them, such as beneath a computer monitor for example.
Modern eyetracking is based on high-speed cameras and graphics processors that measure infrared light reflected from the corneas of the eyes. Although it’s invisible to the human eye, the cameras can use infrared light to generate a gray-scale image in which the pupil is easily recognizable. From the position of the pupil in the image, the eye tracker’s software can work out where the user’s gaze is directed – whether that’s on a computer screen or looking out into the world.
But what’s the use? Well, our eyes can reveal a lot about a person’s intentions, thoughts and actions, as they are good indicators of what we’re interested in. In our interactions with others we often subconsciously pick up on cues that the eyes give away. So it’s possible to gather this unconscious information and use it in order to get a better understanding of what the user is thinking, their interests and habits, or to enhance the interaction between them and the computer they’re using.
Practical uses outside the lab
There are lots of useful applications. For example, in marketing and usability studies, eye trackers are commonly used to study the impact of an advertising campaign or the design of a website. For people who cannot use their arms or are completely paralysed, eye tracking can be used to operate a computer or speech synthesiser: eye-based applications allow them to move a mouse cursor and spell out sentences using only their eyes.
Other more futuristic-sounding applications have been explored, such as appliances that listen to your commands when you look at them: imagine speaking “on” and “off” commands to your lamp, your hi-fi system or your television, which until you looked at them had been in standby. Other examples include automatic scrolling when you have reached the bottom of a screen of text, or automatic pausing of a movie if you look away.
While there are uses for eye tracking in industry and among researchers, firms are now looking seriously at how to make them useful for the general public.
Eye-tracking technology knows your subconscious pizza desires
If you prefer to order your pizza without going through all the trouble of actually speaking, Pizza Hut has just the thing for you — “the world’s first subconscious menu.” You sit down, glance through the menu, and before you say anything or even make a conscious decision, the menu has figured out which toppings you’d like on your pizza and places your order. Pizza Hut recently began testing the technology in some of its UK restaurants.
This mind-reading menu fuses a tablet computer with an eyetracker. The eyetracker measures your eye movements while you scan through 20 toppings, and decides which of the 4,896 possible combinations you want by measuring the amount of time you spend looking at each one. The tablet lets the diners know what it thinks they want – and waits for conscious approval – before sending the order to the kitchen.
Sounds great for the indecisive pizza lover. But is there anything to this “subconscious menu” besides marketing gimmicks?
The science of eye-tracking
Eye Tracking Technology itself is real. Louis Émile Javal first used eyetracking to study reading in the late 19th century, and cognitive psychologists today rely on eyetracking to investigate basic processes like attention, perception, memory, and decision-making.
Eye movement and patterns – are studied to understand human behavior and to assess and diagnose injuries or diseases. You can, for example, perform hearing tests on infants or identify markers of diseases such as Alzheimer’s or autism at a very early stage. The study of Microsaccades is central in neurological research.
Eyetracking is also used as a tool for understanding topics ranging from dyslexia to distracted driving while texting. Cutting-edge cognitive neuroscience research even combines eyetracking with brain imaging to study the neural systems that underlie human thought.
Eyetracking was once expensive and reserved for the well-funded science lab, but in the last couple of years the technology has become widely available. Today, good eyetracking systems can be had for less than a couple of hundred dollars.
Tobii – the same firm that brought us pizza ordering by mind control – recently launched a consumer-priced remote eye tracker, the Tobii EyeX (US$139) with the aim of encouraging games developers to build eye tracking support into their products. For comparison, research lab-grade eye trackers cost around US$20,000.
Interactivity at the cutting edge
There’s a lot of potential for eye tracking in video games. For example, in the popular first-person view (“3D shooter”) style of games, eye tracking can be used to automatically pan the screen to where the player is looking, replacing a task usually performed by the mouse. The eyes can be used to target weapons, too.
One of the most interesting applications is interaction with game characters. When using eye tracking video game characters can be made to react to the player’s gaze the same way a human would. Imagine entering a shop and letting your eyes rest on a sword you find interesting: the merchant could tell you directly about this item, making the interaction more real. Or a character might get upset if, instead of looking at him while he’s talking, your eyes rest on his wife. The eyes are very powerful means of nonverbal communication. Implementing human-like reactions in virtual characters could mean a whole new level of immersion.
Beyond games, there is another range of applications where eye tracking is becoming a hot topic: smart glasses. Because of its shape, a lot of people think Google Glass also tracks the eyes, but it doesn’t. But it wouldn’t be surprising to see the next generation of smart glasses including eye tracking capabilities. This could provide further ways of interacting with the head-up display projected onto the glasses, adding automatic scrolling and navigation that leaves the wearer’s hands free instead of having to use the manual control.