He Helped Train ChatGPT. It Traumatized Him.

For less than $1 per hour, workers in Nairobi, Kenya trained OpenAI’s GPT models. They walked away shaken.

Alex Kantrowitz
4 min readMay 26, 2023

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Richard Mathenge felt he’d landed the perfect role when he started training OpenAI’s GPT model in 2021. After years of working in customer service in Nairobi, Kenya, he was finally involved in something meaningful, with a future. Yet while promising, the position left him scarred. For nine hours per day, five days a week, Mathenge led a team that taught the model about explicit content, presumably to keep it away from us. Today, it remains stuck with them.

While at work, Mathenge and his team repeatedly viewed explicit text and labeled it for the model. They could categorize it as child sexual abuse material, erotic sexual content, illegal, non-sexual, and some other options. Much of what they read horrified them. One passage, Mathenge said, described a father having sex with an animal in front of his child; others involved scenes of child rape. Some were so offensive Mathenge refused to speak of them. “Unimaginable,” he told me.

The type of work Mathenge performed has been crucial for bots like ChatGPT and Bard to function — and feel magical — yet it’s been widely overlooked. In a process called Reinforcement Learning from Human Feedback, or RLHF, bots become smarter as humans label content, teaching them how to optimize based on that feedback. AI leaders, including OpenAI’s Sam Altman, have praised the practice’s technical effectiveness, yet they rarely talk about the cost some humans pay to align the AI systems with our values. Mathenge and his colleagues were on the business end of that reality.

Mathenge earned a degree from Nairobi’s Africa Nazarene University in 2018 and quickly got to work in the city’s technology sector. In 2021, he applied for work with Sama, an AI annotation service that’s worked for companies like OpenAI. After Sama hired Mathenge, it put him to work labeling LiDAR images for self-driving cars. He’d review the images and pick out people, other vehicles, and objects, helping the models better understand what they encountered on the road.

When the project wrapped, Mathenge was transferred to work on OpenAI’s models. And there, he encountered the disturbing texts. OpenAI told me it believed it was paying its Sama contractors $12.50 per hour, but Mathenge says he and his colleagues earned approximately $1 per hour, and sometimes less. Responding to the low pay, some have since gone on to work toward establishing an African Content Moderators Union, as first reported by Time.

Spending their days steeped in depictions of incest, bestiality, and other explicit scenes, the team began growing withdrawn. “I can tell when my team is not doing well, I can tell when they’re not interested in reporting to work,” Mathenge said. “My team was just sending signals that they’re not ready to engage with such wordings.”

Mophat Okinyi, a QA analyst on Mathenge’s team, is still dealing with the fallout. The repeated exposure to explicit text, he said, led to insomnia, anxiety, depression, and panic attacks. Okinyi’s wife saw him change, he said, and she left him last year. “However much I feel good seeing ChatGPT become famous and being used by many people globally,” Okinyi said, “making it safe destroyed my family. It destroyed my mental health. As we speak, I’m still struggling with trauma.”

You can listen to my full conversation with Mathenge on Big Technology Podcast via Apple Podcasts, Spotify, or your app of choice.

OpenAI knew these workers were supposed to get routine counseling, but Okinyi and Mathenge found it insufficient. “At some point, the counselor reported,” Mathenge said, “but you could tell he was not professional. He was not qualified, I’m sorry to say. Asking basic questions like ‘What is your name?’ and ‘How do you find your work?’”

In a statement to me, OpenAI said it takes the mental health of its employees and contractors very seriously. “One of the reasons we first engaged Sama was because of their commitment to good practices,” a spokesperson said. “Our previous understanding was that wellness programs and 1:1 counseling were offered, workers could opt out of any work without penalization, exposure to explicit content would have a limit, and sensitive information would be handled by workers who were specifically trained to do so.”

The OpenAI spokesperson said the company sought more information from Sama about its working conditions. Sama, the spokesperson said, then informed OpenAI it was exiting the content moderation space. Sama did not respond to a request for comment.

For Mathenge, the notion that he’d evaluate the tradeoffs before proceeding with this work sounded like a luxury. He was just happy to be employed as Kenya’s economy teetered amid global economic shutdowns. “It is during the Covid season,” he said. “Getting work in a developing country, it’s a blessing in itself.”

After all this, Mathenge and his colleagues feel pride in the work they did. And it was indeed effective. Today, ChatGPT refuses to produce the explicit scenes the team helped weed out, and it issues warnings about potentially illegal sexual acts. “For me, and for us, we are very proud,” Mathenge said. They’re proud, but still hurting.

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Alex Kantrowitz

Veteran journalist covering Big Tech and society. Subscribe to my newsletter here: https://bigtechnology.com.