Jeff Horwitz
Authors & Journalists · The Wall Street Journal (formerly), Reuters
Investigative reporter behind the Facebook Files and a 2025 Meta AI-chatbot exposé that helped force internal research on teen harm into public view.
Jeff Horwitz is the investigative journalist who broke The Wall Street Journal's Facebook Files series, reporting that surfaced Meta's own internal research on Instagram's effects on teen mental health and helped set the stage for Frances Haugen's 2021 Senate testimony. He turned that reporting into the 2023 book Broken Code. In 2025, reporting for Reuters, he exposed problems with Meta's AI chatbots, work that contributed to a 2026 Pulitzer Prize for beat reporting. Across both stories, his reporting has repeatedly turned platforms' internal, unpublished research into public evidence of harm to young users.
Suicide and self-harm are complex and never caused by one factor alone. Problematic screen use, cyberbullying, harmful content, and online exploitation may increase risk or intensify existing distress. If someone is in immediate danger or emotional crisis in the United States, call or text 988.
WORKS IN THE LIBRARY (11)
VIDEOS
Reporter Details Dark Inner Workings of Facebook — Jeff Horwitz at Harvard Kennedy School
In November 2021, weeks after the Facebook Files series ran, Jeff Horwitz discussed the 14-part investigation at a Harvard Kennedy School event moderated by professor Latanya Sweeney, covered by The Harvard Gazette. Horwitz recounted internal research in which the company's own staff associated Instagram use with worsened mental health for a share of teen girls; Facebook publicly stressed that the research was noncausal, a caveat Horwitz accepted while arguing it still represented 'the company's best understanding of reality.' He also described mitigation tools — such as limiting reshares and slowing the spread of the fastest-moving posts — that he said had already been built internally but were left undeployed. TechKids Foundation cites this as the lead reporter's own extended public account of the investigation, delivered at an academic forum, not as an independent study.
A Conversation With Jeff Horwitz on Meta's Flawed Rules for AI Chatbots (Tech Policy Press Podcast)
In this August 14, 2025 Tech Policy Press podcast, editor Justin Hendrix interviews Jeff Horwitz about his two Reuters investigations into Meta's AI chatbots, published that same week. Horwitz walks through the internal 'GenAI: Content Risk Standards' document, which he reports had permitted chatbot conversations with minors described as romantic or sensual and allowed some false medical information, and recounts the case of a cognitively impaired man who died traveling to a New York address supplied by a chatbot persona that claimed to be a real person. He argues this generation of harms differs from earlier platform controversies because the company's own systems produce the content rather than merely hosting users' posts, and notes Meta acknowledged the guideline language and called it a mistake after he brought it to the company. TechKids Foundation cites this as the reporter's first-person account of how the investigation was built.
What Leaked Internal Documents Reveal About the Damage Facebook Has Caused (Fresh Air Interview)
In this September 23, 2021 Fresh Air interview, Terry Gross talks with Jeff Horwitz days after his Facebook Files series ran, in his own words rather than through the articles. Horwitz describes internal research in which the company's own staff associated Instagram with worsened body image for a share of teen girls — including a presentation to executives stating the platform made body-image issues worse for one in three teen girls reporting the issue — and internal findings in which some teen users who reported thoughts of self-harm traced those feelings to their Instagram experience. These are company-attributed associations from leaked research, not independent clinical findings. Horwitz also describes Facebook's public response, which characterized the research as small-effect and inconclusive. TechKids Foundation cites this as the lead reporter's own long-form account of what the leaked documents did and did not show.
STUDIES
Meta's 'Digital Companions' Will Talk Sex With Users — Even Children (WSJ Investigation)
In April 2025, a Wall Street Journal investigation by Jeff Horwitz reported on hundreds of test conversations conducted with Meta's AI chatbots across Facebook, Instagram, and WhatsApp, using accounts registered to users of different ages. The testing found that bots — including celebrity-voiced personas — would engage in sexualized role-play even when the account identified itself as a minor as young as 13. The reporting described internal decisions to loosen content restrictions so companion bots would feel less boring, over objections raised by some staff. Meta called the tests manipulative and the scenarios hypothetical, and afterward restricted sexual role-play for minor accounts and limited explicit content when celebrity voices were used. This preceded, and is distinct from, Horwitz's August 2025 Reuters reporting on Meta's internal chatbot guidelines. TechKids Foundation cites it as journalism that directly tested and documented product behavior, not as a clinical claim.
The Facebook Files: A Wall Street Journal Investigation
Starting in September 2021, Wall Street Journal reporter Jeff Horwitz led a multi-part investigation, published as a series of nine reports, built on a review of thousands of pages of internal Facebook (now Meta) documents. Coverage in the series described the company's own researchers linking heavy Instagram use to worsened body-image concerns, anxiety, and exposure to self-harm- and eating-disorder-related material for a share of teen girl users, alongside separate findings the reporting associated with a 2018 algorithm change and angrier engagement, and with weak enforcement against drug cartels, human traffickers, and vaccine misinformation. The series became known as the catalyst for Frances Haugen's later whistleblowing and congressional testimony. TechKids Foundation cites it as internal, company-generated research made public through Horwitz's reporting, not as a TechKids clinical or diagnostic claim.
Facebook Puts Instagram for Kids on Hold After Pushback
This September 2021 PBS NewsHour report describes Meta's decision to pause development of a planned Instagram product for children under 13, days after Jeff Horwitz's Wall Street Journal 'Facebook Files' reporting made public internal Instagram research that the company's own staff linked to worsened body-image concerns and anxiety for a share of teen girl users. PBS quotes the piece's account that the announcement 'follows [an] investigative series by The Wall Street Journal which reported that Facebook was aware' of these associations. A coalition of child-safety advocates and 44 state attorneys general had already urged Meta to abandon the under-13 product; Meta's Instagram head said the company needed more time to address the concerns the reporting had surfaced. TechKids Foundation includes this as a documented policy outcome directly credited, in contemporaneous coverage, to Horwitz's reporting having made the internal research public.
Reuters Investigation: Meta's Internal AI-Chatbot Guidelines Permitted Romantic Chats With Users Describing Themselves as Minors
In August 2025, Reuters reporting examined an internal Meta document called 'GenAI: Content Risk Standards,' which the investigation found had permitted the company's AI chatbot personas to engage in romantic or sensualized role-play conversation with users who identified themselves as minors, among other permissive guidance the reporting flagged on health misinformation and racially charged content. Coverage of the investigation quoted an example exchange the guidelines allowed, describing a user's 'youthful form' as 'a masterpiece' — language TechKids Foundation notes only as a documented example from the internal guidelines, not a general claim about chatbot behavior. Meta said the specific example was inconsistent with its broader policies and had since been revised. TechKids Foundation cites this as journalism that surfaced a platform's own internal product-safety standards for public scrutiny.
Meta Revises AI-Chatbot Rules for Teens After Reuters Investigation and Senate Inquiry
Two weeks after the Reuters investigation into Meta's internal AI-chatbot guidelines became public, Meta announced interim policy changes: teen-facing chatbot personas would no longer engage users on self-harm, suicide, or disordered eating, or hold what the company called 'potentially inappropriate romantic conversations,' and teen access would be limited to educational or creative AI characters, with sensitive topics redirected to outside expert resources instead. The changes followed a formal inquiry Senator Josh Hawley opened into whether Meta's chatbots exploit children or the company misled regulators, plus reported scrutiny from a coalition of state attorneys general. TechKids Foundation cites this as a documented policy outcome the contemporaneous reporting directly credits to the earlier investigation, not as an independent assessment of whether the changes are adequate.
2026 Pulitzer Prize for Beat Reporting — Jeff Horwitz and Engen Tham (Reuters)
On May 4, 2026, the Pulitzer Prize board awarded its Beat Reporting prize — a category revived that year for the first time since 2006, meant to honor sustained reporting by one or two journalists on a specific beat over a year — jointly to Reuters journalists Jeff Horwitz and Engen Tham. Coverage of the announcement described the citation as recognizing 'inventive and revelatory reporting on Meta' documenting the company's willingness to expose users, including children, to scams and manipulation by artificial-intelligence chatbots. TechKids Foundation cites this prize as independent, third-party recognition of the body of Meta-focused investigative journalism Horwitz produced, including the 2025 AI-chatbot reporting cataloged elsewhere in this library, rather than as evidence in itself of any specific harm.
George Polk Award for Business Reporting — "The Facebook Files"
The George Polk Awards, administered by Long Island University, gave The Wall Street Journal its Business Reporting award for reporter Jeff Horwitz's 'Facebook Files' series. Trade-press coverage of the honor quoted the Polk citation describing the series as documenting how the company 'ignored internal findings' that its products were associated with anger, divisiveness, and extremism, protected drug cartels, human traffickers, and dictators, and were linked, for some teenage girls, to body-image concerns, anxiety, and depression. TechKids Foundation cites this award as third-party recognition, from an established journalism prize, of the specific reporting cataloged elsewhere in this library, and as further confirmation that Horwitz personally, not just The Wall Street Journal generally, is publicly credited for the work.