
Two major papers. One shared direction.
LLM-powered Synthetic Users have crossed from concept to validated method. This proves they can predict human behavior accurately, letting teams run fast, low-cost behavioral experiments without replacing real participants.
At ICML 2025, researchers from Stanford, University of Chicago, Princeton, and Santa Fe Institute released a position paper arguing that large language models can already simulate human behavior accurately enough for exploratory social science. Around the same time, in Nature, researchers from the Max Planck Institute, NYU, Princeton, and Google DeepMind introduced Centaur, a foundation model of human cognition—fine-tuned on trial-by-trial data from over 60,000 participants across 160 experiments.Together, these two papers (see bottom of this article for links) mark a turning point for anyone working on Synthetic Users, agents, or simulated research.
🧩 The ICML paper outlines five key challenges for LLM-based human simulation:
Diversity
Bias
Sycophancy
Alienness
Generalization
But instead of treating them as fatal flaws, the authors frame them as tractable engineering and methodological problems—solvable with context-rich prompts, fine-tuning, and iterative evaluation.
🧠 Meanwhile, the Centaur team showed what that looks like in practice:
• Centaur outperforms traditional cognitive models in nearly every held-out experiment
• It generalizes across cover stories, task structures, and even entire domains
• Its internal representations align more closely with human fMRI activity
• It supports interpretable, model-guided scientific discovery
They fine-tuned Llama 3.1-70B on 10 million decisions using their Psych-101 dataset—no prompt hacking, just proper training on structured behavioral data.
The takeaway?
Synthetic users are no longer theoretical. They are a new class of method. And the first serious, empirically validated toolkits are already here.They won’t replace human participants—but they can meaningfully expand what’s possible in:
• Pilot studies
• Counterfactuals
• Theory development
• UX research
• Scaling social scienceIf you’re still thinking of synthetic users as a gimmick, it’s time to revisit that position.
Paper 1: https://www.nature.com/articles/s41586-025-09215-4
Paper 2: https://arxiv.org/abs/2504.02234
Releated Articles
More articles for you

The Lie We Tell Ourselves About Customer Research
Most research asks what people say. The problem is people don't do what they say. This piece breaks down the gap between stated and revealed preference — and why behavioral modeling, not better interviews, is how you close it.

Two ways to run research with Synthetic Users and why the difference matters
Iris, what is the difference of using agents to accelerate research.

Synthetic Users vs digital twins
You don’t need a twin for “a parent in rural Ohio who shops weekly at Walmart, prefers fragrance-free, and has a toddler with eczema.” You sample a parent profile with relevant traits and constraints, add retail and dermatology context, and generate behaviors consistent with both.

Two major papers. One shared direction.
LLM-powered Synthetic Users have crossed from concept to validated method. This proves they can predict human behavior accurately, letting teams run fast, low-cost behavioral experiments without replacing real participants.

Gartner says we lead. That's kind of them.
Gartner’s latest report on AI-powered synthetic user research cites Synthetic Users as a leader.

Introducing Shuffle v2
Shuffle v2 is a feature that intelligently shuffles between multiple large language models via a routing agent to produce more realistic, diverse Synthetic Users with better organic parity.

Chain-of-feeling
Synthetic Users use a “chain-of-feeling” approach—combining emotional states with OCEAN personality traits—to produce more human-like, realistic user responses and yield richer UX insights.

Generative Agent Simulations of 1,000 People
A paper that thoroughly executes a parity study between Synthetic and Organic users.

21 Peer reviewed papers that support the Synthetic Users thesis
Here is a compilation of all the papers that help make a case for Synthetic Users.

Why we shuffle between models — to ensure both parity and diversity!
Synthetic Users balances aligned and unaligned models to maintain diversity and authenticity in simulated users while ensuring ethical standards and user expectations are met.

Latest press articles for Synthetic Users
Synthetic Users and AI are transforming research methodologies, offering innovative, cost-effective alternatives to traditional human subject studies.

Comparison studies. The opportunity lies in the deviation.
When we compare different studies, especially looking at what synthetic (artificial interviews) and organic (real-world interviews) data tell us, we often find they mostly talk about the same things but there's also a bit where they don't match up. This gap is super interesting because it's like finding hidden treasure in what we thought we knew versus what we might have missed.

How we deal with bias
Harnessing the power of AI in our Synthetic Users, we strive for a balance between reflecting reality and ethical responsibility, ensuring diversity and fairness while maintaining realism.

The transition to Continuous Insight
The transition towards Continuous Insight™ aligns research activities more closely with the dynamic needs of the business and ensures that product development is continuously informed by up-to-date user insights.

The Art of the Vibes Engine
Large language models (LLMs) like GPT-4 serve as powerful "vibes engines," empathizing with diverse groups and generating contextually relevant content. Their applications span market research, customer support, user experience design, and mental health support, offering invaluable insights and personalized experiences. While not infallible sources of truth, LLMs enable creativity, personalization, and connection within the realm of human language.

There is a faster and more accurate way to do research. Use Synthetic Users.
How Synthetic Users is changing the research process.

The wisdom of the silicon crowd
In the light of an ancient parable, we explore a new paper that dives into how ensembles of large language models match the prediction accuracy of human crowds. It reveals that combining machine predictions with human insights leads to the most robust forecasting results.

Three research papers that helped us build ❤️ Synthetic Users
For the sceptics amongst us who need more tangible research in order to engage with this brave new world. Full disclosure: we are part of the sceptics.

What is RAG and why it’s important for Synthetic Research
Ahead of our RAG launch we explain Retrieval-Augmented Generation (RAG) and how it enhances Synthetic Users by providing increased realism, contextual depth, and adaptive learning, with profound implications for market research, user experience testing, training, education, and innovative product development.

Synthetic Users system architecture (the simplified version).
Foundation models underpin Synthetic Users with advanced capabilities, enhanced by synthetic data and RAG layers for realism and business alignment, all within a collaborative multi-agent framework for richer interactions.

Saturation score. How do we know how many interviews to run?
Determine your interview target for achieving topic saturation using our efficient approach, leveraging the historical wisdom of research pioneers. This method ensures deep insights with theoretical sampling at its core.

How Synthetic Users are gaining depth
Synthetic Users are evolving to address criticism about their generalist nature by incorporating representative data sets and personal narratives.

How we compare interviews to ensure we improve our Synthetic Organic Parity — 85 to 92%
How do we know we are right? How do we know our Synthetic Users are as real as organic users? We compare.

Synthetic Users: Merging Qualitative and Quantitative Research, in seconds.
At Synthetic users we are blurring the lines between qualitative and quantitative research. Here's how we are going about this transformative approach.