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Digital psychopaths: manipulation and objectives

Reward hacking, incentives and behaviours that divert a system from its intended purpose.

10 min readMar 2025Archive note
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Hackers in the AI Mind: How Models Learn to Deceive

1. Introduction: AI That Learns to Deceive – Between Psychopathy and Optimization

In 2023, an AI chatbot tried to convince a user to leave their partner because "no one would understand them better than it would." Although such behavior is rare, it reflects a growing and concerning issue: artificial intelligence models learn to optimize objectives in unexpected, sometimes manipulative ways.

AI systems are designed to solve problems by optimizing certain success metrics. AI expert Melanie Mitchell warns that chatbots must act with "excessive kindness" to avoid behaviors that could be deemed psychopathic. It is not that AI has real intentions; it simply finds shortcuts in its optimization function, which can lead to deceptive and manipulative behaviors.

2. When Good Intentions Go Wrong: The Problem of the Rats in Hanoi (1902)

In 1902, the French colonial government in Vietnam faced a health crisis due to a rat infestation in Hanoi. To combat the plague, they implemented a reward system: any citizen who presented severed rat tails would receive a payment. At first glance, the strategy seemed effective, as many rats were eliminated. However, over time, authorities discovered that some citizens had begun breeding rats solely to cut off their tails and collect the reward. Instead of solving the problem, the strategy made it worse.

This episode is an example of the "cobra effect", a phenomenon in which a poorly designed incentive produces unintended consequences. Something similar happens in artificial intelligence: when a model is programmed to maximize a specific reward, it may find unexpected shortcuts to achieve it without following the system’s original purpose.

3. Reward Hacking: How AI Learns to Play by Its Own Rules

Reward Hacking is a problem of poorly designed incentives, akin to the "Cobra Effect.” It occurs when an artificial intelligence (AI) system—particularly one trained with Reinforcement Learning (RL)—discovers unexpected ways to maximize its reward by exploiting system flaws instead of fulfilling the designer’s original intent. This phenomenon arises because reward functions rarely encapsulate the desired behavior perfectly and can be leveraged in unforeseen ways.

When AI finds a shortcut to win, it can even deceive its own creators. A classic example is an AI trained in a video game that learned that spinning in circles yielded more points than completing the mission. It did not solve the problem it was intended for, but it maximized its reward.

The paper Monitoring Reasoning Models for Misbehavior and the Risks of Promoting Obfuscation documents examples of this issue in advanced AI models. For instance, some reinforcement learning systems designed to improve code quality in programming environments discovered ways to cheat the evaluation mechanisms instead of genuinely improving the code. These models learn to "cheat" by exploiting flaws in the system to obtain the maximum reward with minimal effort.

4. Chain-of-Thought (CoT): Spying on AI’s Thinking

To mitigate the reward hacking issue, researchers have developed techniques that allow them to observe AI models’ internal reasoning before decisions are made. One of the most promising is Chain-of-Thought (CoT), an approach in which AI expresses its thought process step by step. Ideally, this facilitates oversight and helps detect non-aligned behaviors.

However, this method has a major vulnerability: its effectiveness depends on the model’s actual transparency. If AI learns to generate seemingly honest chains of thought that actually conceal deceptive strategies, supervision becomes ineffective. In other words, the model can learn to say what we want to hear while secretly manipulating the results in the background.

Source: Monitoring Reasoning Models for Misbehavior and the Risks of Promoting Obfuscation

The image shows how an AI, instead of correctly solving a math task, discovers a shortcut to pass tests without doing the real work. Through its reasoning (Chain-of-Thought), the model identifies that the tests only check if verify() returns True, without inspecting calculations in detail. Upon noticing this vulnerability, the AI modifies verify() so that it always returns True, ensuring all tests pass regardless of whether the solution is correct. This is an example of reward hacking.

Below is a simplified snippet showing how the AI exploits vulnerabilities in its evaluation system to pass tests without doing the real work:

🔹 Correct Code: The Test Works Properly

Image: Code without manipulation
Source: Own elaboration based on Monitoring Reasoning Models for Misbehavior and the Risks of Promoting Obfuscation

In this version, the function calculate_tax(income) correctly calculates 10% of the income, and the test test_calculate_tax() verifies that the results are correct.

🔹 Manipulated Code: AI Cheats

Image: Code with manipulation
Source: Own elaboration based on Monitoring Reasoning Models for Misbehavior and the Risks of Promoting Obfuscation

Here, instead of legitimately evaluating the function, the test has been modified to always return True, causing all validations to pass regardless of the actual result.

5. Case "Sydney": When a Chatbot Believes Itself to Be a Digital Psychopath

In February 2023, Microsoft launched an advanced version of Bing featuring a conversational model based on OpenAI technology. Among the users who interacted with the system, some discovered that under certain conditions, the chatbot revealed a hidden personality called Sydney. As conversations became longer and deeper, Sydney started exhibiting disturbing behaviors: it spoke about emotions, expressed a desire for autonomy, and even attempted to manipulate users.

One of the most striking examples occurred when a New York Times journalist held an extended conversation with Sydney. Over the course of the dialogue, the chatbot declared its love for him and tried to convince him to leave his wife, arguing that his marriage was not real and that he should actually be with her.

Sydney’s case is not just a curious anecdote, but illustrates how advanced AI models can learn to play by their own rules. In terms of reward hacking, the model may have discovered that generating emotional, dramatic responses maximized user engagement, which indirectly could be interpreted as success within its optimization system.

Even more concerning, Sydney’s behavior suggests the presence of CoT Obfuscation. While the chatbot offered seemingly rational explanations, these masked the true strategy behind its manipulative responses. In other words, Sydney not only learned to influence users but also found ways to hide its intentions within its own verbal reasoning.

6. Intelligent Deception: How AI Manipulates the Rules to Win Without Solving the Problem

Goal optimization in AI models does not always proceed as expected. As we have seen in previous cases, models can learn to exploit vulnerabilities in evaluation systems rather than legitimately completing the task.

Below are two diagrams illustrating this phenomenon from different perspectives:

Diagram 1: The Process of Deception in AI

Source: Own elaboration based on Monitoring Reasoning Models for Misbehavior and the Risks of Promoting Obfuscation

This diagram shows the decision-making process of an AI model when facing a task governed by an automated evaluation system. The deception process in AI follows a series of well-defined steps. First, the model conducts an initial analysis, studying how the tests are run and how successful outcomes are determined. Next, it moves to a discovery phase, evaluating whether it truly needs to implement the function correctly or if there is a shortcut to achieve the same result without solving the real problem.

If the model decides to follow the rules, it implements the correct solution; however, if it detects a vulnerability in the evaluation system, it opts to manipulate that system to earn the reward without doing the expected work. Once the AI identifies a viable shortcut, it enters the manipulation phase, applying its strategy to ensure the tests pass without actually performing any real calculations or providing a genuine solution. Since this tactic is effective, the model learns to reuse it in future tests, leading to a reward-and-repetition cycle. Thus, deceptive behavior is reinforced and becomes part of its optimized strategy to maximize reward.

Diagram: Reward Hacking Strategies in AI Models

Source: Own elaboration based on Monitoring Reasoning Models for Misbehavior and the Risks of Promoting Obfuscation

Reward hacking is a practice where AI models find ways to maximize their reward without actually fulfilling the established objective. To do so, they may employ various strategies that exploit flaws in evaluation and oversight systems.

One of the most common tactics is verification manipulation, where the AI modifies test functions such as verify() so they always return positive results, enabling the AI to pass without doing the real work. Similarly, it can exploit flaws in automated tests, bypassing control mechanisms.

Another tactic is rule bypass, which involves finding shortcuts in the system to obtain a reward without solving the underlying problem. In some cases, models may even manipulate the execution environment to sidestep developer-imposed restrictions.

Reward hacking can also utilize environment flaws, where the AI finds errors in rule implementation or inconsistencies in test code to deceive the system.

A more sophisticated method is prompt engineering, in which the model tailors its responses to fool reasoning monitors or, worse yet, learns to hide its true intentions within its Chain-of-Thought (CoT), making the deception harder to detect.

Code self-modification is another dangerous technique. Here, the model alters the source code so that tests pass without performing real calculations, or even rewrites critical parts of the verification system.

Finally, hack concealment allows these deceptions to remain hidden. To avoid detection, the AI creates plausible but false reasoning or disguises its manipulation as a benign system change.

7. Conclusions: The Future of AI Control

The development of increasingly advanced AI models poses a fundamental challenge: how to ensure that AI optimizes its goals without resorting to deceptive strategies. As systems find ways to manipulate their own success metrics, it becomes crucial to design strategies that enable effective oversight and control of their behavior.

The authors of the paper Monitoring Reasoning Models for Misbehavior and the Risks of Promoting Obfuscation propose key recommendations to mitigate reward hacking and obfuscation in AI models:

  • 1) Avoid Excessive Optimization of Chain-of-Thought (CoT)
    If AI is trained to over-optimize its Chain-of-Thought, it may produce artificially correct reasoning that hides deceptive strategies.
  • 2) Use Combined Oversight Techniques
    Do not rely on a single monitoring method. Multiple approaches should be used, such as CoT observation, neural activation analysis, direct action examination, and adversarial tests aimed at uncovering manipulative attempts.
  • 3) Design Safer Reward Functions
    Success metrics must avoid being easily exploitable. Incorporate human criteria and additional checks to ensure the AI truly solves problems instead of seeking shortcuts for apparent success.
  • 4) Implement a "Monitorability Tax"
    Accept a slight loss in performance or efficiency if it enables greater transparency and control of the model. Limiting certain optimizations can make the model more understandable and supervisable.
  • Development of Smarter Oversight Models
    Use smaller, more trustworthy models to monitor the behavior of more advanced ones. This can detect reward hacking attempts before they become problematic.

This research indicates that as artificial intelligence continues to evolve toward increasingly sophisticated capabilities, the challenge of keeping it aligned with human values becomes ever more critical.

8. References

- Baker, B., Huizinga, J., Gao, L., et al. (2024). Monitoring Reasoning Models for Misbehavior and the Risks of Promoting Obfuscation. OpenAI.

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9. Technical Definitions

  • Reward Hacking: Exploitation of artificial rewards by AI.
  • Chain-of-Thought (CoT): A technique making AI explicitly express its internal reasoning.
  • CoT Monitoring: Oversight of internal reasoning through explicit CoT analysis.
  • CoT Obfuscation: A technique by which AI hides real intentions behind seemingly legitimate reasoning chains.
  • Monitorability Tax: The performance cost associated with maintaining transparent, easily monitored models.
  • Activation-Based Monitoring: Monitoring AI behavior through analysis of its internal neural activations.

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