Social media, we know, tends to reinforce our beliefs, make us more hostile towards different opinions and close us in information bubbles, making civil confrontation with those who think differently increasingly difficult. This dynamic, however, may not be inevitable. A study published in Science in 2025 by Stanford University shows that it is possible to reduce polarization by intervening from the outside, without changing the platform’s algorithm.
Researchers have developed an AI-powered browser extension that reorders posts in the X feed. By showing the least polarizing content first and leaving the most polarizing content last, users become more open-minded towards those on the opposing political spectrum. Reversing the order of posts, however, increases hostility.
For now the tool only works on X and only in the browser version. The extension code, however, has been published in full, so as to allow other research groups to develop similar tools for other platforms. The research group also declared that it is working on a version that can be used directly within the apps, even if the implementation is technically more complex.
Let’s see how this tool works, how the experiment was designed and what effects it produced.
How it works: AI scores posts and reorders them
The research team built a browser extension, that is, a small program that you add to your browser – such as Chrome or Firefox – to add new features. In this case, the extension changes the order of posts in the X feed.
Every time a user opens the social network from the browser, the extension analyzes a group of approximately 35 posts. A first language model, i.e. an AI such as ChatGPT, Claude or Gemini, identifies those that contain statements of a political nature. These are then sent to a second model, which evaluates the level of polarization. To do so, it takes into consideration various factors, including support for political violence, aggressive language towards the opposing side and the distorted representation of political events. He then assigns each post a score ranging from 0, not at all polarizing, to 8, extremely polarizing.
At this point the extension does not modify or delete any content, but simply reorders the posts. If the goal is to reduce polarization, show those with the lowest scores first. If you want the opposite effect, bring those with the highest ratings to the top of the feed.
Tested on 1,200 US participants before the presidential election
To test and verify the effects of this extension, Stanford University recruited over 1200 participants, all Americans and users of X. About two thirds identified themselves as Democrats, while the remaining third as Republicans. The experiment took place in the weeks immediately preceding the 2024 US presidential elections, one of the most tense moments in the political debate.
Participants were randomly assigned to two separate, parallel experiments. In the first, the feed was reordered to reduce exposure to polarizing content, in the second to increase it. Each experiment also included a control group, whose feed remained unchanged, so that the effects produced by the extension could be compared.
The effects of the experiment, which lasted a week, were measured through a series of questionnaires. The researchers assessed both the emotions felt while scrolling through X’s feed and attitudes toward the opposing party, a measure known as “affective polarization.”
Those who see less polarizing content are more open to the opposing party
From this experiment it became clear that the contents we are exposed to influence the way we perceive those who have different political ideas from ours. Exposure to more polarizing content made participants more hostile towards the opposing party, while a feed composed of more moderate content increased openness towards those belonging to the opposing political party.
These effects were measured through the “emotional thermometer”, a scale from 0 to 100 used to evaluate the degree of appreciation or hostility towards the other party. Both effects exceeded 2 degrees. This effect may seem very small, but it is a change comparable to about three years in the average evolution of affective polarization in the United States. The shift was seen among both Democratic and Republican voters.
Participants exposed to more polarizing content also reported feeling angrier and sadder during the experiment due to the content they were exposed to. These emotions, however, were temporary and do not seem to explain the effects observed on affective polarization.
This study shows that it is possible to make social media less polarizing by intervening on the way content is presented to users, without necessarily removing it or limiting its diffusion. The tool developed by the researchers currently works only on browsers, via Chrome and Edge, and only on X. However, the extension code has been made public together with a detailed technical guide, so as to allow other research groups and developers to replicate the experiment and create similar tools for other platforms.
