Cool study, bro: Why Reddit comments degrade over time

May 04, 2016

Prolonged online sessions seem to take a toll on attention span and user-generated content quality. Time spent online can play a key role in shaping how we talk on social media.

Contact: Andrew Good at (213) 740-8606 or gooda@usc.edu.

A big data analysis of Reddit comments has revealed how online social activity wears on our mental faculties.

The study, under review at PLOS ONE, measured how the quality of Internet posts degrades over time. It looked at about 55 million comments posted to Reddit during April of 2015 (~40 million after filtering for spam and bots). For users who engaged in commenting without breaks longer than an hour, persistent activity resulted in poorer performing posts: they successively became shorter in length, generated fewer upvotes and responses, and received a lower “readability score,” calculated based on the level of education a reader would need to comprehend it.

The study was co-authored by Emilio Ferrara and Kristina Lerman of the USC Viterbi School of Engineering’s Information Sciences Institute. They conducted the research to see if they could better quantify online social activity and how information spreads within networks.

“We wanted to see whether these kind of cognitive operations effects the performance of the individuals,” Ferrara said. And they found that it does: “As your usage sessions become longer, your language becomes more elementary, less complex — your content becomes less interesting, in a sense.”

Ferrara and Lerman’s study notes that performance deterioration has already been documented in contexts such as studying, driving, data entry and exerting self-control. While the exact brain mechanisms causing this are debated, it’s generally agreed that there is a physiological basis at root. How these same physiological changes play out in the digital world is something both researchers hope to further understand.

Still, they cautioned against reading too deeply into the study’s measure of cognitive effects. They weren’t able to measure the actual impact on the brain during online social activity — just how observable “performance” fared over time.

“I think this shows that our brains don’t have infinite capacity,” Lerman said of the study’s results. “As we spend more time on the Internet, it does decline the decision-making abilities we have.”

Ferrara speculated there may be one easy way to resist these degrading effects: closing your browser. He said it’s possible that some users may be taking breaks in between online sessions, resulting in higher comment quality. It’s also possible that some users have higher thresholds for online performance, he added.

“One thing that fascinates me is whether there’s a correlation between levels of performance and the popularity of these users,” Ferrara said. “As your popularity increases systematically with content, either you have a larger capacity for cognitive performance or you’re implementing some strategies — like taking breaks between browsing sessions.”

This first study looked at activity across an aggregate of users, but Ferrara and Lerman hope to further refine their results. In future studies, they’re interested in looking at the behaviors of distinct types of users. Varying personality types may perform differently online. The distinctions between highly active users versus casual ones could also play a role.

While this particular study focused on Reddit, the authors said ongoing research had found similar results for platforms such as Facebook and Twitter. On Twitter, as a session progresses, users tend to compose fewer and shorter messages, preferring instead to retweet the posts of others.

The authors’ research work is supported in part by DARPA, the Army Research Office, and the Office of Naval Research.