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As technology and machine learning continue to advance, we’re integrating surveillance into our daily lives at an increasing rate, and the level of surveillance is becoming more sophisticated. It’s easy to overlook all the ways we’re being tracked, but as soon as you start to quantify it, it quickly becomes unsettling. And it may make you wonder: what effect does being watched all the time have on your behavior—and your brain? Turns out, it can be just as mentally taxing as mental disorders like depression, and can even cause symptoms similar to post-traumatic stress disorder.

Let’s begin by trying to quantify just how much the average American is being tracked, because it’s not always apparent. When news of a massive breach breaks, we become more vigilant momentarily, but experts say that the surveillance we’re aware of is only the tip of the iceberg.

“When we think of surveillance, people traditionally think of the standard forms of embodiment like CCTVs or spies tapping a phone line,” Christopher Burr, a researcher at the Digital Ethics Lab at the University of Oxford, told me in a Skype interview. “But that doesn’t really capture the general character of what’s becoming increasingly more possible, and more and more effective.”

Burr studies the philosophy of cognitive science and artificial intelligence, and his research has investigated the different kinds of data that can be scraped from human interactions with machines. In a recent study, which has not yet been published, Burr and his colleagues used data from computer science competitions to try to catalog what sort of information can be pulled from our everyday interactions with computers. They were surprised to find the breadth of data that can be gleaned. Programmers have been able to measure someone’s job satisfaction through facial recognition, or parse a Facebook post to detect signs of depression, or even determine someone’s heart rate through a webcam.

“The way that the blood sort of flows through the skin and the way the skin signals this can be detectable, not perfectly accurate, but it can be detectable through a webcam,” Burr told me. “This is my day job. I spend a minimum of 40 hours a week researching this topic and I was still surprised by the possibilities.”

Burr also noted that data which is collected for one purpose can often be mined for information it was never intended to convey, as what happened with the Cambridge Analytica election scandal, where the profiles of 50 million Facebook users were leaked and used to inform targeted advertising during the 2016 presidential election.

“The fear and uncertainty generated by surveillance inhibit activity more than any action by the police.”

The impact these different forms of surveillance has on any of us depends on a couple of things: how aware we are that we’re being watched, and what we think the motivation is for surveillance, according to Brock Chisholm, a clinical psychologist who has studied the effects of surveillance on mood and behavior. Chisholm gave me the example of a study he did on human rights defenders who were campaigning in Ethiopia and under surveillance.

“They suddenly had images that their family could be arrested, that they could be arrested, some people had post-traumatic stress disorder-like symptoms,” Chisholm said in a phone interview. “What we sometimes call flash-forwards, rather than flashbacks.”

It all depends on the context, and in that sense our reaction is no different than other animals, Chisholm explained. A baby rat being watched by its mother will feel comforted and safe. A baby rat being watched by a predator would feel stressed and threatened.

In parts of the world, surveillance is constant for certain groups of people—think about journalists and human rights activists living under authoritarian regimes. It’s such a pervasive issue that its chilling effects are sometimes taken for granted by those they affect, according to Joshua Franco, a senior research advisor and the deputy director of Amnesty Tech at Amnesty International.

“The fear and uncertainty generated by surveillance inhibit activity more than any action by the police,” Franco said in a phone interview. “People don’t need to act, arrest you, lock you up and put you in jail. If that threat is there, if you feel you’re being watched, you self-police, and this pushes people out of the public space. It is so hard to operate under those types of conditions.”

Franco told me many people living under these structures are so used to having to look over their shoulder and watch what they say, that it becomes second nature. And even when they escape these situations, the threat of surveillance can have long term effects on their lives.

Image: Roel Wijnants/Flickr

“For a lot of people, those harms are quite invisible,” Franco said. “Uzbekistan refugees in Europe, for example, may fear that calls home are being monitored because receiving a call from a foreign number could get people in trouble with local authorities. So they’re forced to cut off contact.”

And government surveillance is becoming more widespread as invasive technology becomes more affordable and readily-available, Franco said. Compared to the Stasi, the secret police in East Germany prior to German reunification, who needed hundreds of thousands of informants to gather information on civilians, governments can now buy software that reads emails and records phone calls for them.

But even in democratic societies, we’ve invited a lot of surveillance willingly into our lives. Different people will accept different levels and forms of surveillance, too. Many of us know that Netflix tracks our viewing patterns and uses an algorithm to recommend new shows and movies, but we’re comfortable with this surveillance because the trade off seems worth it; the kind of data we’re sharing is worth the benefit we receive in more accurate recommendations.

“The reaction from the mental health community has been similar to society at large, which is that we’ve given up on trying to protect ourselves."

This dictates how our knowledge of being watched—and whether we have consented to it—may impact us, and if we’re not comfortable with the amount or way we’re being surveilled, or we don’t think it’s worth the trade off, it can cause anxiety, and potentially an insidious form of anxiety that is particularly dangerous for our health.

“There’s the kind of background, everyday anxiety that builds up, we know it’s there, but we kind of ignore it and we don't realize how on edge we were until it’s gone,” Chisholm said. “For those people, the kind of lower level but building up background anxiety—they're going to have more relationship difficulties, more arguments, they’re going to be more hypervigilant, scanning for threats.”

So what do we do? As much as many of us may have fantasized about crushing our devices with a pickup truck and driving to the forest to become a hermit (just me?), the reality is that most of us are not able to escape at least some level of surveillance in our lives.

“The reaction from the mental health community has been similar to society at large, which is that we’ve given up on trying to protect ourselves. It almost feels like nothing can be done,” said Dr. Elias Aboujaoude, a behavioral psychology researcher at Stanford University.

Unplugging, and taking control over what information is tracked, can alleviate some of these anxieties.

“An aspect of meaning when it comes to surveillance comes down to control, so if you can find times when you feel you’re not being surveilled, that would help,” Chisholm said. “I actually think one of the main problems is that people don’t think about it enough and companies are able to get away with things that are ultimately harmful. I think there are some benefits to people feeling a little bit more unsafe.”