It’s been known for a long time that knowing that someone might be listening to you changes the way people behave. The risk that you might be under surveillance means you don’t speak your mind freely. This is in many ways one of the primary functions of surveillance in authoritarian states: it is one of the most effective supressors of anti-government speech in private as well as in public. When even private conversations are considered to be potentially overheard, potentially public, you bite your tongue and don’t tell your friends how the Stasi, the Junta, the tyrant really makes you feel.
This is known as the chilling effect on free speech. It’s been a known criticism of authoritarian states for a long time. And now, of course, also of the United States of America. It turns out that this effect can be scaled up. Way, way up.
Being scared that your exact phone might be tapped produces different actions. But it turns out that the very knowledge that you are under constant surveillance, that everything is stored for posterity, even if you specifically are not “targeted”, causes self-censorship.
Participants in the study were first surveyed about their political beliefs, personality traits and online activity, to create a psychological profile for each person. A random sample group was then subtly reminded of government surveillance, followed by everyone in the study being shown a neutral, fictional headline stating that U.S. airstrikes had targeted the Islamic State in Iraq. Subjects were then asked a series of questions about their attitudes toward the hypothetical news event, such as how they think most Americans would feel about it and whether they would publicly voice their opinion on the topic. The majority of those primed with surveillance information were less likely to speak out about their more nonconformist ideas, including those assessed as less likely to self-censor based on their psychological profile.
This demonstrates powerfully that a natural public life requires a natural private life. We need to have a reasonable expectation of privacy at all times. As John Stuart Mill, the great philosopher of freedom of speech, wrote in On Liberty, it is precisely the most unheard, but held, opinion that needs to be voiced. The NSA has made a machine for subtly, but profoundly eroding freedom of speech.