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The Privacy-Invading Potential of Eye Tracking Technology

Jay Stanley,
Senior Policy Analyst,
老澳门开奖结果 Speech, Privacy, and Technology Project
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May 6, 2013

Eye tracking technology received new attention recently due to its inclusion in the Samsung Galaxy IV phone, where it can (with mixed results, according to reviewers) let users scroll the screen with their eyes or dim the screen when they look away. Clearly this is a technology that has the potential for a lot of clever applications. But what are the privacy implications?

Eye tracking for research was used for over a century before computers (see the quick history outlined in ). The earliest research, in the 19th century, actually involved direct mechanical contact with the cornea. Already by 1898, researchers were discovering some phenomena of the human brain. Motion pictures were applied to the problem as early as 1905, and the first head-mounted eye-tracker was developed in 1948, which freed study subjects from having to keep their heads still. In the mid-1970s the first remote trackers were developed that were truly unobtrusive to the subject. By then, research and writing based on eye tracking was booming, not only on the part of psychologists but also the military.

In recent years much seems to have been focused on 鈥渉uman-computer interaction鈥濃攎easuring how the human brain processes various user interfaces, web pages, graphics in layouts, approaches, etc., and how best to optimize those things. By tracking the eyes of someone sitting in front of a computer viewing a scene, researchers can measure 鈥渟canpaths鈥濃攖he order in which somebody looks at an image or scene鈥攐r create 鈥渇ixation maps,鈥 in which the time that the eye lingers at various points in an image (鈥済aze durations鈥) is measured. Take a look at this to get a taste of the complexity of the science in this area. is an analysis of users鈥 gazes at Facebook pages (of keen interest to advertisers and marketers).

UCLA electrical engineering professor John Villasenor has written about the privacy implications of eye tracking on the phone and in . The technology is still not 鈥渜uite ready for mass-market adoption,鈥 he notes, but:

Once the technology for eye-tracking is in place, it will glean information conveying not only what we read online, but also how we read it. Did our eyes linger for a few seconds on an advertisement that, in the end, we decided not to click on? How do our eyes move as they take in the contents of a page? Are there certain words, phrases, or topics that we appear to prefer or avoid? In the future, will we be served online ads based not only on what we鈥檝e shopped for, but also on the thoughts reflected in our eye movements?

Those are the kinds of things that much eye tracking research has focused on to date, in the context of a human sitting at a computer, and are certainly where the near-term privacy threats lie. But it鈥檚 possible that the privacy threat from this technology could reach far beyond one鈥檚 computer or smartphone screen. It鈥檚 not hard to imagine that eye tracking could get good enough to be targeted at a person in public, at a distance鈥攑erhaps even someone walking down a sidewalk. Already studies comparing how shoppers scan different stores鈥 window displays. Those studies used photographs, but the incentive to develop live tracking is obvious.

Meanwhile, progress is likely to continue on another front: research on what we can learn about people by tracking their gaze. As one eye tracking expert , 鈥渆ye movement data provide an unobtrusive, online measure of visual and cognitive information processing.鈥 Combine the two, and we could see the technology become a standard part of an analytics toolbox plugged in to every surveillance camera fixed on the public.

Among the things that eye tracking has or could be used to try to discover about us:

  • Cognitive disorders. Research has that autism, , dyslexia, and could be diagnosed using eye tracking.
  • Drug and alcohol use. Alcohol and drug use has been to have effects on eye movements, as does fatigue.
  • Mental and psychological illness. Schizophrenia is another disorder that research already eye tracking may be able to detect. is yet another. Eye tracking has also been suggested as a way to detect and .
  • HIV/AIDS. Individuals infected with HIV sometimes contract a disorder called AIDS Dementia Complex, which can be with eye tracking.
  • Lie detection. Lie detection is a notorious sinkhole of pseudoscience鈥攖he link between high-level mental states such as 鈥渢ruthfulness鈥 and low-level, involuntary external behavior is just too ambiguous and unreliable鈥攂ut the quest for lie detection continues, and are being made about the usefulness of eye tracking for this.
  • Intelligence. A significant amount of eye tracking research appears to have been focused on and how humans scan various texts. It鈥檚 not hard to imagine that the technology could reveal insights into how different people think, analyze, and process information. I guarantee it wouldn鈥檛 be long before someone starts searching for, or claiming, a correlation with criminality, as we have in the area of genetic research.
  • Sexuality. In a quick search I found some tracking 鈥渧isual attentional capture鈥 in the viewing of erotic images, and men and women. I would think that by putting a sexualized image containing both an attractive man and an attractive woman, one could probably tell a lot about who is gay and who is straight from the scanpaths and fixation points of people walking by. (Or more precisely, how attracted to men and how attracted to women each subject is.) One did find changes in pupil size could reveal gender attraction.

The application of eye-tracking technology on the general public via video cameras is, at the present time, science fiction鈥攂ut clearly not far-future sci-fi. And regardless of how much of the above ever comes to pass, it鈥檚 yet another reminder of the huge wave of privacy-invading technology that is headed our way, and of our need to get ready for that.

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