[Paper]
[Code]
Recently, large pre-trained language models (LLMs) have demonstrated superior language understanding abilities, including zero-shot causal reasoning. However, it is unclear to what extent their capabilities are similar to human ones. We here study the processing of an event \(B\) in a script-based story, which causally depends on a previous event \(A\). In our manipulation, event \(A\) is stated, negated, or omitted in an earlier section of the text. We first conducted a self-paced reading experiment, which showed that humans exhibit significantly longer reading times when causal conflicts exist (\(\neg A \rightarrow B\)) than under logical conditions (\(A \rightarrow B\)). However, reading times remain similar when cause A is not explicitly mentioned, indicating that humans can easily infer event B from their script knowledge. We then tested a variety of LLMs on the same data to check to what extent the models replicate human behavior. Our experiments show that 1) only recent LLMs, like GPT-3 or Vicuna, correlate with human behavior in the \(\neg A \rightarrow B\) condition. 2) Despite this correlation, all models still fail to predict that \(nil \rightarrow B\) is less surprising than \(\neg A \rightarrow B\), indicating that LLMs still have difficulties integrating script knowledge. Our code and collected data set are available at https://github.com/tony-hong/causal-script.