CU Boulder researchers built AI ghosts of dead people and let their loved ones chat with them and it went way better than expected

Leave it to the University of Colorado to invent a way to text with dead people and have it somehow not be creepy.

Researchers at CU Boulder just published the first-ever user experience study of “generative ghosts” — AI chatbots trained on data about deceased loved ones — and the results caught even the scientists off guard. “We originally thought it might feel very Black Mirror creepy to people and make them uncomfortable,” said Jack Manning, a PhD candidate in information science and the study’s lead author. “I ended up being completely wrong. People thought it was amazing.” Manning’s own sister died from a heart condition when they were children, giving the research a deeply personal dimension.

The study, published by the Association for Computing Machinery, recruited 16 participants ages 22 to 50 who had lost a close friend or relative. During individual Zoom sessions, a facilitator gathered biographical details and memories about the deceased while a second researcher quietly built an AI ghost in real time using a large language model. Participants then chatted with two versions: one that spoke in the first person, as if it were their loved one talking, and one that spoke in the third person, like a representative describing them. The preference was unanimous — everyone wanted the ghost that talked like their person, not about their person. One participant nearly ended the session when a ghost of their stepfather called them “champ,” a word the man had never used. Small factual mistakes were forgivable. Getting the vibe wrong was not.

Every single participant said they’d use a generative ghost again — but nearly all of them also flagged the same concern: that grieving people could become addicted to it. “We anticipate that within our lifetimes it may become common practice for people to create custom AI agents to interact with loved ones and the broader world after their death,” said Jed Brubaker, an associate professor of information science at CU Boulder and the study’s senior author. Companies like HereAfter AI and Project December are already selling the concept commercially, inviting people to upload voice recordings, photos and memories while they’re still alive so their loved ones can chat with their AI ghost after they’re gone. The CU team has already begun follow-up research analyzing the mental health impacts.

Colorado: where we legalized weed, pioneered the arcade bar, and are now leading the nation in talking to dead people through a computer. Honestly, it tracks.