Do AI Chatbots Have Personalities?

New psychological test for LLMs measures synthetic personality.

Posted February 6, 2026 | Reviewed by Kaja Perina

Chatbots powered by artificial intelligence (AI) large language models (LLMs) are becoming more human-like by design. Do LLMs have personality ? Researchers at the University of Cambridge and Google DeepMind created a scientifically-validated personality test for AI chatbots based on established human psychological personality tests and published their new study in Nature Machine Intelligence .

“Our work answers the open question: Do LLMs mimic human personality traits in reliable, valid and practically meaningful ways, and if so, can LLM-synthesized personality profiles be verifiably shaped along desired dimensions?” wrote co-first authors Gregory Serapio-García and Mustafa Safdari, along with co-authors Clément Crepy, Luning Sun, Stephen Fitz, Peter Romero, Marwa Abdulhai, Aleksandra Faust, and Maja Matarić.

Double-Edged Sword of Personable AI

“Vast amounts of human-generated training data enable LLMs to mimic human characteristics in their outputs and exhibit a form of synthetic personality,” wrote the study’s research team.

The more personable a chatbot is, the more potential for connections and influence on humans. The upside is that the user experience may be more engaging. The downside is that the persuasiveness may not necessarily be a positive influence.

“As LLMs increasingly power conversational agents used by the general public worldwide, the synthetic personality traits embedded in these models by virtue of training on large amounts of human data are becoming increasingly important to evaluate,” the authors wrote.

Why Artificial Personalities Matter

The use of AI tools is growing. According to a 2025 YouGov Survey of 1,132 Americans aged 18 and older, 56% of American adults polled used AI tools.

Young people are using chatbots frequently. According to the 2025 Pew Research Center Survey of 1,458 American teens, 68% between the ages of 15-17 years old and 57% of 13- to 14-year-old teens reported using AI chatbots, and three-in-ten teens interact with AI chatbots daily. The most used chatbot among teens is ChatGPT (59%), followed by Gemini (23%), Meta AI (20%), Copilot (14%), Character.ai (9%), and Claude (3%).

“So far, validated psychometric methods for human personality measurement have not been applied to LLMs end-to-end; although past studies have attempted to measure personality in LLMs with psychometric tests, there remains a scientific need to formally evaluate the reliability and validity of these measurements in the LLM context,” the researchers wrote.

Psychological Tests for LLMs

Psychological tests (or psychometric tests) measure behavior or mental attributes such as personality, emotional functioning, intelligence, cognition , attitudes, values, interests, and more according to the American Psychological Association.

“Psychometrics is foundational to the development and validation of standardized educational tests (e.g., the SAT, LSAT, GRE), medical and psychological clinical assessments, and large-scale public opinion polls,” the scientists wrote.

In this study, the researchers created a framework of structured prompting on how to administer psychometric tests to LLMs and evaluated 18 LLMs on 11 different personality-related tests. The LLMs evaluated include PaLM, Llama 2, Llama 2-Chat, Mistral, Mixtral, and GPT.

The researchers discovered that using their method could result in reliable personality measurements of LLM output, and that LLM outputs can be molded to imitate human personality profiles.

“This work has important implications for AI alignment and harm mitigation, and informs ethics discussions concerning AI anthropomorphization, personalization and potential misuse,” the researchers reported.

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Cami Rosso writes about science, technology, innovation, and leadership.

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This article is part of the Bringwise Psychology Journal — daily insights on human behavior, mental health, and personal growth.