Fictional Facebook post
To test the hypotheses Stoycheff conducted an experiment with 255 participants to whom she presented a fictional Facebook post "about U.S. airstrikes against ISIS in Iraq and asked to imagine that they came across it in their news feeds. [...] Participants were subsequently asked about their willingness to publicly express their opinions on this topic, their perceptions of how other Americans felt about this topic, the extent to which they believed online surveillance justified, and demographic information."

To simulate the sense of 'being watched', about half of the participants were actively reminded of the NSA's data collection capabilities, while the rest was not.

Conforming behavior
The test yielded interesting results when the participants were placed in three categories based on their judgement about government surveillance. The first group opposes surveillance, the second tolerates it, and the third supports it.

Stoycheff found that people who are opposed to government surveillance are hardly affected by it when it comes to speaking their mind. They are almost as willing voice their opinion in a hostile climate of opinion as they are in a friendly one. When reminded of government surveillance their willingness to speak out in general diminishes a little, but whether the climate of opinion is friendly or hostile, has no effect.

People who approve of government surveillance, on the other hand, show a huge drop in willingness to express their opinion when they think they are being watched and perceive a hostile environment. What is more, they are more likely to express there opinion when they conform to the dominant view.

The middle group, those who tolerate surveillance, showed behavior similar to that of surveillance supporters, though less pronounced.

For these last to groups - which constituted the majority of participants - the spiral of silence applies. Under the watchful eye of the government, these groups will speak out more when they hold the majority opinion and less when they belong to the minority.

Mass online surveillance therefore, is detrimental to a healthy democratic debate which thrives on the free exchange of opposing opinions, Stoycheff warns. "This study shows [government surveillance] can contribute to the silencing of minority views that provide the bedrock of democratic discourse".