Causal reasoning is a fundamental property of human and machine intelligence. While large language models (LLMs) excel in many natural language tasks, their ability to infer causal relationships beyond memorized associations is debated. This study systematically evaluates recent LLMs’ causal reasoning across three levels of Pearl’s Ladder of Causation—associational, interventional, and counterfactual—as well as commonsensical, anti-commonsensical, and nonsensical causal structures using the CLadder dataset. We further explore the effectiveness of prompting techniques, including chain of thought (CoT), self-consistency (SC), and causal chain of thought (CausalCoT), in enhancing causal reasoning, and propose two new techniques causal tree of thoughts (CausalToT) and causal program of thoughts (CausalPoT). While larger models tend to outperform smaller ones and are generally more robust against perturbations, our results indicate that all tested LLMs still have difficulties, especially with counterfactual reasoning. However, our CausalToT and CausalPoT significantly improve performance over existing prompting techniques, suggesting that hybrid approaches combining LLMs with formal reasoning frameworks can mitigate these limitations. Our findings contribute to understanding LLMs’ reasoning capacities and outline promising strategies for improving their ability to reason causally as humans would. We release our code and data.

We present a large-scale evaluation of 30 cognitive biases in 20 state-of-the-art large language models (LLMs) under various decision-making scenarios. Our contributions include a novel general-purpose test framework for reliable and large-scale generation of tests for LLMs, a benchmark dataset with 30,000 tests for detecting cognitive biases in LLMs, and a comprehensive assessment of the biases found in the 20 evaluated LLMs. Our work confirms and broadens previous findings suggesting the presence of cognitive biases in LLMs by reporting evidence of all 30 tested biases in at least some of the 20 LLMs. We publish our framework code and dataset to encourage future research on cognitive biases in LLMs: https://github.com/simonmalberg/cognitive-biases-in-llms.