Lindsay Popowski

Lindsay Popowski

@popowski.bsky.social

phd-ing @ stanford hci online groups, social platform design, and mental models. also books. books books books.

523 followers366 following20 posts

Lindsay Popowski reposted

Positech is back #CSCW2026 ! Join the wonderful group of organizers for a day of collaborative discussions on how social technologies can help people build the capacity to care about global challenges in ways that are both effective and sustainable :)

Lindsay Popowski@popowski.bsky.social

People today are drowning in awareness of suffering with nowhere productive to put it. This is a problem that social technology research can and should tackle! At our #CSCW2026 workshop, we’ll spend the day exploring how to design toward sustainable care. Apply by Aug 3: positech.github.io/cscw2026

Lindsay Popowski reposted

Empirical evidence that people can build highly predictive mental models of even complex AIs, if and only if the algorithm fulfills three criteria:

Lindsay Popowski@popowski.bsky.social

Is the only way we can create algorithms that people understand to make them trivially simple? We argue, no. People can predict the behavior of algorithms that are arbitrarily complex, if and only if they are available, compact and aligned. arxiv.org/abs/2601.18966

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Alignment is the factor with greatest flexibility, perhaps because people are used to errors in their algorithms. Users are willing to tolerate relatively high error rates if a single obvious feature has more signal than noise, e.g., if the like count is highly correlated.

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These properties also shape which mental models users deploy when reasoning about algorithm behavior. Users default to incorporating highly available engagement signals into their mental models regardless of whether they are present in the underlying algorithm.

When users cannot explain an algorithm with one clear idea, they often juggle multiple (incorrect) mental models. Compactness becomes a kind of crumple zone: by vaguely combining additional factors, users avoid being clearly proven wrong.

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We test this theory in a large pre-registered study (N=1250) where participants predicted the behavior of 25 social media feed-ranking algorithms systematically varying the ACA properties, ranging from single-feature rankings to complex, LLM-based systems.

We find that users predict algorithm behavior accurately if and only if all three properties hold, regardless of algorithmic complexity. For non compliant algorithms, prediction accuracy falls to around chance.

It is tempting to say that unpredictability is inevitable as algorithms grow more complex, in our social media feeds and beyond. But that intuition fails. Predictability hinges instead on whether users can faithfully translate an algorithm’s behavior into a usable mental model.

Three factors matter here: (cognitive) availability means the algorithm is built on concepts users already reason with, (conceptual) compactness means those concepts cohere to a single construct, and alignment means people and the algorithm apply the concept in similar ways.

Lindsay Popowski reposted

Our new article in @science.org enables social media reranking outside of platforms' walled gardens. We add an LLM-powered reranking of highly polarizing political content into N=1256 participants' feeds. Downranking cools tensions with the opposite party—but upranking inflames them.

Lindsay Popowski reposted

a couple of hours before my keynote, I went through an intense negotiation with the organisers (for over a hour) where we went through my slides and had to remove anything that mentions 'Palestine' 'Israel' and replace 'genocide' with 'war crimes' 1/

Dr Abeba Birhane@abeba.blacksky.app

my keynote happening in a few mins. registration here to stream it aiforgood.itu.int/summit25/reg...

Lindsay Popowski reposted

i think it is a sign of low character to post something controversial knowing it will get angry comments and then insult the people who responded to your ragebait

Lindsay Popowski reposted

AI companions aren’t science fiction anymore 🤖💬❤️ Thousands are turning to AI chatbots for emotional connection – finding comfort, sharing secrets, and even falling in love. But as AI companionship grows, the line between real and artificial relationships blurs.

what is stanford hci going to do without our funniest member next year?

Tiziano Piccardi@tiziano.bsky.social

I'm so excited to join the CS department at Johns Hopkins University (@jhu.edu) as an Assistant Professor! I'm looking for students interested in social computing, HCI, and AI—especially around designing better online systems in the age of LLMs. Come work with me! piccardi.me

Lindsay Popowski reposted

I'm so excited to join the CS department at Johns Hopkins University (@jhu.edu) as an Assistant Professor! I'm looking for students interested in social computing, HCI, and AI—especially around designing better online systems in the age of LLMs. Come work with me! piccardi.me

Lindsay Popowski reposted

I'm excited to announce that I’ll be joining the Computer Science department at Johns Hopkins as an Assistant Professor this Fall! I’ll be working on large language models, computational social science, and AI & society—and will be recruiting PhD students. Apply to work with me!

Lindsay Popowski reposted

BREAKING: We're sending an open letter to universities across the country, offering support and urging them to reject pressure to punish international students and faculty for exercising their First Amendment rights. Schools must hold firm against the Trump administration's censorship attempts.

Lindsay Popowski reposted

I just sent our university president and provost an urgent request to defend First Amendment freedoms at Stanford, given this administration’s willingness to punish those who disagree with it. I urge you to do the same with your university leaders.

Lindsay Popowski reposted

Replying to @dwillner.bsky.social

Zuck positioned these changes as a return to history practice but, for these policy changes, that is untrue. The specific examples I called out above have been prohibited on the site since I wrote the first set of hate speech standards in 2009. 🧵 8/11

Lindsay Popowski reposted

Dismantling the fact-checking infrastructure is going to be super handy when things start going wrong in the new administration and they want to redirect blame onto the left.

Lindsay Popowski reposted

My advisor warned me that academics trend towards bitterness. He encouraged me to intentionally resist this, remember where I came from, and never forget the privilege of getting to spend a life working with knowledge and ideas. He too said that bitterness and resentment is easy.

Julia Angwin@juliaangwin.com

In high school, my social studies teacher took me aside and told me that "cynicism was the easy path" and that I needed to resist it. It's probably the most important thing I learned in school.

Lindsay Popowski reposted

The future (imo) will be filled with a constant ache and continual search for — with increasingly diminished capacity for discovery / identification of — authenticity.

Dave Karpf@davekarpf.bsky.social

I am fascinated by the people at Meta who think this is a *good* idea in exactly the same way I'm fascinated by conspiracy theorists. It just seems so patently awful to me. And in ways that every sensible person I know would immediately grasp.

Lindsay Popowski reposted

hey coca cola is officially on the BDS list now so no more buying Topo Chico or starlight coke or whatever else they make

Lindsay Popowski reposted

New paper: Do social media algorithms shape affective polarization? We ran a field experiment on X/Twitter (N=1,256) using LLMs to rerank content in real-time, adjusting exposure to polarizing posts. Result: Algorithmic ranking impacts feelings toward the political outgroup! 🧵⬇️

Lindsay Popowski reposted

Academic job market post! 👀 I’m a CS Postdoc at Stanford in the Stanford HCI group. I develop ways to improve the online information ecosystem by designing better social media feeds & improving Wikipedia. I work on AI, Social Computing, and HCI. piccardi.me 🧵

Lindsay Popowski reposted

This paper argues that online spaces become ghost towns because it's too easy to lurk without contributing, and that asking people to regularly re-commit—or the incoming messages start getting muted—reverses the trend. arxiv.org/abs/2410.23267 It works! #cscw2024 paper by @popowski.bsky.social .

arxiv.orgCommit: Online Groups with Participation CommitmentsIn spite of efforts to increase participation, many online groups struggle to survive past the initial days, as members leave and activity atrophies. We argue that a main assumption of online group de...

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