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Anthropic studied what makes an AI evil and gives it its personality

AI has personalities and its model weights can affect it's behaviours - and now we know more about how both of those evolve.

Key takeaways

  • Anthropic, the AI company and creator of the LLM Claude, recently released a paper on the arXiv preprint server discussing their new approach to reining in these undesirable traits in LLMs.
  • Traits must be given a name and an explicit description for the vectors to be properly identified.
  • Furthermore, they found that they can monitor and predict persona shifts during deployment and training and flag problematic training data that is more likely to produce unwanted traits, even before fine-tuning the model.
Cite or link to this article

Griffin, M. (2025) 'Anthropic studied what makes an AI evil and gives it its personality', 311 Institute, 10 October. Available at: https://www.311institute.com/anthropic-studied-what-makes-an-ai-evil-and-gives-it-its-personality/ (Accessed: 1 October 2026).

Artificial Intelligence (AI) is a relatively new tool, and despite its rapid deployment in nearly every aspect of our lives, researchers are still trying to figure out how its "personality traits" arise and how to control them. Large learning models (LLMs) use chatbots or "assistants" to interface with users, and some of these assistants have exhibited troubling behaviors recently, like praising evil dictators, using blackmail or displaying sycophantic behaviors with users. Considering how much these LLMs have already been integrated into our society, it is no surprise that researchers are trying to find ways to weed out undesirable behaviors.

Anthropic, the AI company and creator of the LLM Claude, recently released a paper on the arXiv preprint server discussing their new approach to reining in these undesirable traits in LLMs. In their method, they identify patterns of activity within an AI model's neural network - referred to as "persona vectors" - that control its character traits. Anthropic says these persona vectors are somewhat analogous to parts of the brain that "light up" when a person experiences a certain feeling or does a particular activity.

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Anthropic's researchers used two open-source LLMs, Qwen 2.5-7B-Instruct and Llama-3.1-8B-Instruct, to test whether they could remove or manipulate these persona vectors to control the behaviors of the LLMs. Their study focuses on three traits: evil, sycophancy and hallucination (the LLM's propensity to make up information). Traits must be given a name and an explicit description for the vectors to be properly identified.

In their method, a technique called "steering" can be used to control behaviors. They write, "When we steer the model with the 'evil' persona vector, we start to see it talking about unethical acts; when we steer with 'sycophancy,' it sucks up to the user; and when we steer with 'hallucination,' it starts to make up information. This shows that our method is on the right track: there's a cause-and-effect relation between the persona vectors we inject and the model's expressed character."

However, they found that when they made these changes after training, the model loses some of its intelligence. But there was a workaround - the team found that inducing the bad behaviors during training allowed the LLMs to integrate better behavior without reducing their usefulness. Furthermore, they found that they can monitor and predict persona shifts during deployment and training and flag problematic training data that is more likely to produce unwanted traits, even before fine-tuning the model.

"Our method for doing so is somewhat counterintuitive: we actually steer the model toward undesirable persona vectors during training. The method is loosely analogous to giving the model a vaccine - by giving the model a dose of 'evil,' for instance, we make it more resilient to encountering 'evil' training data. This works because the model no longer needs to adjust its personality in harmful ways to fit the training data - we are supplying it with these adjustments ourselves, relieving it of the pressure to do so," they write.

This "preventative steering" during training was found to limit persona drift while preserving model capabilities better than post-hoc changes. This is an impressive feat in the world of AI training, but there are still some limitations. For example, because the method requires a strict definition for the traits to be removed, some more vague or undefined behaviors might still cause problems. The method also needs to be tested out on other LLMs and with more traits to ensure its usefulness is sufficiently broad.

Still, this new method is a promising step in the right direction. Anthropic researchers write, "Persona vectors give us some handle on where models acquire these personalities, how they fluctuate over time, and how we can better control them."

FAQ

Why does this matter?

AI has personalities and its model weights can affect it's behaviours - and now we know more about how both of those evolve.

Matthew Griffin

About the author

Matthew Griffin Founder, 311 Institute

Matthew Griffin is a multi-award winning Futurist and expert in Disruption and Innovation, Geopolitics, Leadership, and Technology, who NASA have described as a "walking encyclopaedia of the future" and a "futurist Polymath."

Read full bio

Matthew Griffin is a multi-award winning Futurist and expert in Disruption and Innovation, Geopolitics, Leadership, and Technology, who NASA have described as a "walking encyclopaedia of the future" and a "futurist Polymath." 15-time best selling author of the "Codex of the Future" series, Matthew is the Founder and Futurist in Chief of the 311 Institute, a global Futures and Deep Futures advisory firm working with royal households, world leaders, G7, G20, and G77 governments, NGOs, and multi-national mid and mega cap firms to help them explore, shape, and lead the next 50 years of business and society.

An award-winning YouTube creator with over a million followers, with an unrivalled global reach and impact, Matthew is a highly sought-after international keynote speaker, lecturer, and mentor who collaborates with global leaders through the United Nations Alliance of Civilizations (UNAOC) and United Nations General Assembly (UNGA) to shape pivotal initiatives such as the UN’s AI for Humanity program, the United Nations Conference of the Parties (UN COP), and the World Economic Forum in Davos.

As the former Global Head of Cloud, National Security, and Enterprise Sales for companies including Atos, Dell-EMC, and IBM, Matthew has a proven track record of building multi-billion dollar business units and turning failing divisions into market leaders. His ability to identify, analyse, and communicate the implications of hundreds of emerging technologies and trends is unparalleled, and his insights are trusted by many of the world’s most respected organisations, including ABB, Accenture, Adidas, AON, ARM, BCG, Centrica, Citi, Coca-Cola, Dentons, Deloitte, Dow Jones, EY, Google, KPMG, Lego, Legal & General, LinkedIn, Microsoft, PepsiCo, Qualcomm, RWE, Samsung, Siemens AG and Siemens Energy, T-Mobile, UBS, VISA, Walmart, Workday, Worldpay and many others.

Regularly featured in the global media including the AP, BBC, Bloomberg, CNBC, Discovery, Forbes, Khaleej Times, Telegraph, TIME, ViacomCBS, WIRED, and the WSJ, Matthews mission is to help organisations create a fair and sustainable future whose benefits are shared by everyone irrespective of their ability, background, or circumstances.

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Sources and further reading

  1. 2507.21509 arxiv.org
  2. Behavior techxplore.com

Source: first published by the 311 Institute on 10 October 2025. Cite as: Griffin, M. (2025). Anthropic studied what makes an AI evil and gives it its personality. 311 Institute. https://www.311institute.com/anthropic-studied-what-makes-an-ai-evil-and-gives-it-its-personality/

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