Understanding Formalism Trap
Most AI teams focus solely on optimising fairness metrics like demographic parity or equalised odds rather than aligning AI to address real-world concerns like equity or accessibility.
For example, the Formalism Trap emerges when Fairness—a profoundly human and social concept—is oversimplified into purely mathematical terms.
Fairness is inherently multifaceted, encompassing:
- Procedural Fairness means acting fairly to make decision-making processes transparent and consistent with meaningful participation.
- Contextual Fairness: Recognising how varying contexts affect Fairness.
- Contestable Fairness: Providing mechanisms to question and challenge decisions, ensuring accountability and adaptability.
These critical dimensions extend beyond what algorithms alone can fully address, and there is no one-size-fits-all concept.
The Formalism Trap arises when we reduce Fairness to something that can be solved purely through mathematics. However, Fairness is more than equations—it is about people and the social context.
Why We Cannot Simplify Everything into Algorithms
Daniel Kahneman’s work on naturalistic decision-making highlights a critical insight: real-world decisions are deeply influenced by context, intuition, and experience (Klein, 2008). Unlike controlled environments where algorithms excel, real-world situations are uncertain, complex, and shaped by inherent biases that cannot always be codified into mathematical rules.
Daniel Kahneman (2017) distinguishes between two types of thinking:
- System 1: Fast, automatic, and intuitive decision-making with little or no effort.
- System 2: Involves deliberate and analytical thinking, used for complex reasoning and problem-solving.
Algorithms are found to emulate System 2 thinking, attempting to analyse data methodically and provide an “optimal” decision for structured problems. However, they often fail in dynamic, high-stakes environments where human intuition (System 1) plays a crucial role.
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An Example of The Formalism Trap in Machine Learning
Take lending decisions, for example, from Weerts (2021). A machine learning model might be designed to optimise creditworthiness based on historical data, but it cannot easily incorporate unquantifiable factors like an applicant’s resilience during financial hardship. Therefore, the machine learning model’s decision space is limited to approving or rejecting a loan application. This binary view ignores the human nuances of financial decisions. In reality, many more actions may be available, such as recommending a different type of loan or offering financial education to applicants.Â
The project’s failure to consider these options was a clear case of the Formalism Trap. By forcing a rich, multifaceted problem into a narrow mathematical frame, the system could not account for what “fairness” meant in the broader context of lending practices.
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Design Mitigations for The Formalism Trap
Breaking free from the Formalism Trap is not easy, but it is essential if we want to create AI systems that are both effective and equitable. The product team needs to formulate the problem so that a mathematical algorithm can understand it by considering how different definitions of fairness, including mathematical formalisms, help solve different groups’ problems by addressing different contextual concerns.
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Conclusion
Fairness is not a box you check—it is a process. Some of the most successful projects I have worked on embraced this reality, iterating based on ongoing feedback from affected communities and stakeholders.
Avoiding the Formalism Trap is not just about building better AI systems but also about building trust. We create technically robust and socially responsible systems when we approach Fairness with humility, acknowledging its complexity and engaging with the people it impacts. If you ever felt fairness metrics fell short or struggled to relate them to real-world challenges, I’d love to hear your thoughts. Let us keep this conversation going because Fairness is too important to leave to algorithms alone.
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