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 “human-computer interaction”—measuring 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 “scanpaths”—the order in which somebody looks at an image or scene—or create “fixation maps,” in which the time that the eye lingers at various points in an image (“gaze durations”) 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’ 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 “quite ready for mass-market adoption,” 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’ve 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’s possible that the privacy threat from this technology could reach far beyond one’s computer or smartphone screen. It’s not hard to imagine that eye tracking could get good enough to be targeted at a person in public, at a distance—perhaps even someone walking down a sidewalk. Already studies comparing how shoppers scan different stores’ 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 , “eye movement data provide an unobtrusive, online measure of visual and cognitive information processing.” 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—the link between high-level mental states such as “truthfulness” and low-level, involuntary external behavior is just too ambiguous and unreliable—but 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’s not hard to imagine that the technology could reveal insights into how different people think, analyze, and process information. I guarantee it wouldn’t 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 “visual attentional capture” 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—but clearly not far-future sci-fi. And regardless of how much of the above ever comes to pass, it’s 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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Press ReleaseDec 2024
Free Speech
National Security
ACLU and Partners Urge Supreme Court to Block TikTok BanACLU and Partners Urge Supreme Court to Block TikTok Ban
WASHINGTON — Today, the American Civil Liberties Union, the Electronic Frontier Foundation (EFF), and the Knight First Amendment Institute at Columbia University filed an amicus brief urging the Supreme Court to block the enforcement of a law that would effectively ban people in America from using TikTok as soon as January 19, 2025. Earlier this month, the U.S. Court of Appeals for the D.C. Circuit rejected TikTok’s challenge to the law. TikTok has asked the Supreme Court for a temporary injunction to prevent the app from being banned while the court considers whether to take the case, saying that unless the justices intervene, the law will “shutter one of America’s most popular speech platforms the day before a presidential inauguration.” “The Constitution imposes an extraordinarily high bar on this kind of mass censorship,”said Patrick Toomey, deputy director of ACLU’s National Security Project. “The Supreme Court should take up this important case and protect the rights of millions of Americans to freely express themselves and engage with others around the world.” The brief argues that the D.C. Circuit failed to fully address the law’s profound implications for the First Amendment rights of the 170 million Americans who use TikTok. While the lower court’s decision correctly recognized that the statute triggers First Amendment scrutiny, it barely addressed users’ First Amendment interests in speaking, sharing, and receiving information on the platform. The court also perplexingly attempted to cast the government’s ban on TikTok as a vindication of users’ First Amendment rights, which it is not. The rights groups also explain that the law was intended to suppress certain content and viewpoints that many legislators believe could be amplified on TikTok, including the risk of foreign “propaganda.” But under the First Amendment, the government must meet a very high bar to restrict speech based on concerns about its “motivating ideology” or “perspective,” and the government has not come close to meeting that bar here. “The government should not be able to restrict speech, especially to the extent here, based on guessing about the mere possibility of uncertain future harm,” said David Greene, civil liberties director at EFF. “The Supreme Court should put the TikTok ban on hold while it considers the DC Circuit’s erroneous ruling.” Finally, the brief underscores that the government can’t impose this type of sweeping ban unless it’s necessary to prevent extremely serious and imminent harm to national security. But the government has not provided evidence of impending harm, or evidence that banning TikTok is the only available way to address its concerns. As the brief explains, the D.C. Circuit improperly treated the government’s invocation of “national security” as a trump card and failed to hold the government to its burden. “Restricting citizens’ access to foreign media is a practice that has long been associated with repressive regimes, and we should be very wary of letting the practice take root here,” said Jameel Jaffer, executive director at the Knight First Amendment Institute at Columbia University. “It would do lasting damage to the First Amendment and our democracy if the Supreme Court let this ban go into effect even temporarily.” You can find the brief online here: https://www.supremecourt.gov/DocketPDF/24/24A587/335380/20241217144322392_24A587%20TikTok%20v%20Garland%20Amicus%20Brief%20pdfa.pdf -
Press ReleaseDec 2024
National Security
Religious Liberty
ACLU Statement on New White House Strategy to Counter IslamophobiaACLU Statement on New White House Strategy to Counter Islamophobia
WASHINGTON – The Biden administration today released the first-ever national strategy to counter Islamophobia and related forms of bias and discrimination, including hate against Arab, Sikh, and South Asian Americans. In advance of the strategy, American Civil Liberties Union and its partners had urged the administration to overhaul government programs that reflect anti-Muslim discrimination. In particular, we have called for urgent action to constrain governmental agencies from continuing to exercise their authorities and technology to wrongly surveil and investigate, watchlist, and question and detain Muslims at the border, as well as deny immigration benefits to people from Muslim-majority countries. While the White House raised expectations that many of these issues would be addressed, the final strategy ended up falling far short. The following is a statement from Hina Shamsi, director of the ACLU’s National Security Project: “While this strategy acknowledges discrimination and its harms, it does little to end them and is a squandered opportunity. For decades, American officials have invoked national security to pass laws and implement programs that disproportionately harm Muslims and people perceived to be Muslim. A serious anti-discrimination strategy would concretely address multiple bias-infused government practices that deny our communities equal participation in civic life and our democracy, like federal watchlisting, surveillance, and investigation. We’re profoundly frustrated that the administration didn’t take even the basic, overdue step of recognizing that anti-Muslim discrimination is uniquely normalized and embedded in government policies.” -
VirginiaDec 2024
National Security
Trabelsi v. Crawford, et al. – Lawsuit Challenging Unlawful Detention and Inhumane Treatment of Acquitted ManTrabelsi v. Crawford, et al. – Lawsuit Challenging Unlawful Detention and Inhumane Treatment of Acquitted Man
Our client, Nizar Trabelsi, is in the United States against his will. The federal government brought him here from Belgium more than a decade ago and charged him with terrorism-related crimes. At trial, the government’s case failed: a federal jury found Mr. Trabelsi not guilty. But instead of allowing Mr. Trabelsi to return to Belgium after his acquittal, the United States placed him in highly restrictive immigration detention and began an ongoing effort to force him to Tunisia, where he was born and where he will very likely be tortured. Mr. Trabelsi’s detention violates the Constitution, immigration law, and the extradition treaty between the United States and Belgium. Through this lawsuit, he seeks to return to Belgium, and he demands an immediate improvement of his detention conditions. -
Press ReleaseDec 2024
National Security
Immigrants' Rights
Federal Judge Rejects Acquitted Man’s Argument That His Immigration Detention Is UnlawfulFederal Judge Rejects Acquitted Man’s Argument That His Immigration Detention Is Unlawful
ALEXANDRIA, Va. — This week, the U.S. District Court for the Eastern District of Virginia ruled that the court does not have jurisdiction to decide whether the government can continue to detain Nizar Trabelsi, a Tunisian national who was brought to the United States against his will for prosecution and was cleared of all charges last year. The ruling means the United States will be able to continue to detain Mr. Trabelsi while it attempts to deport him to Tunisia, where he was born and where, as an immigration judge ruled earlier this year, he will likely face torture. The court also concluded that even if it did have jurisdiction over Mr. Trabelsi’s case, his claims challenging the government’s detention of him would fail. “Reviewing claims that the government is holding someone unlawfully is at the core of the judicial function, and we’re heartbroken for our client that the court got this so wrong,” said Brett Max Kaufman, senior staff attorney with the ACLU’s Center for Democracy. “The government’s arguments in defense of Mr. Trabelsi’s detention makes a hash of the Constitution, immigration laws, and its own extradition treaty.” In 2013, the United States forcibly extradited Mr. Trabelsi from Belgium to face criminal charges in the United States. In July 2023, after almost 10 years of highly restrictive pretrial detention, a federal jury cleared Mr. Trabelsi of all charges. But instead of releasing Mr. Trabelsi or returning him to Belgium, the U.S. transferred him to immigration detention, wrongly treating him as an applicant for admission and placing him in the deportation process. Over the years, the Belgian government has issued multiple formal diplomatic requests asking the U.S. to facilitate his return, but the U.S. has refused to send him back. Mr. Trabelsi filed a lawsuit challenging the government's authority to detain him. He also sought immediate improvements to his detention conditions. Those claims were not part of the court’s ruling today, and will continue to be litigated on a separate track. “Mr. Trabelsi only wants to return to Belgium after being illegally extradited to the United States, held for ten years, and then acquitted by a jury of any crimes,” said Nicole Hallett, clinical professor of law and director of the Immigrants’ Rights Clinic at the University of Chicago Law School. “He cannot be held indefinitely and we will continue to fight to make sure that justice ultimately prevails.” Mr. Trabelsi is represented by the American Civil Liberties Union, the University of Chicago Law School’s Immigrants’ Rights Clinic, the ACLU of Virginia, and Professor Jonathan Hafetz of Seton Hall Law School. The complaint in Trabelsi v. Crawford was filed against Jeffrey Crawford, warden of the Farmville Detention Center where Mr. Trabelsi is being held; Liana Castano, ICE field office director for the Washington Field Office; Alejandro Mayorkas, secretary of the Department of Homeland Security; and Merrick Garland, U.S. attorney general.