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Oyvind Tafjord

25 accepted papers

2026

SimpleToM: Exposing the Gap between Explicit ToM Inference and Implicit ToM Application in LLMs

ICLR 2026poster

Large language models (LLMs) are increasingly tested for a "Theory of Mind" (ToM) — the ability to attribute mental states to oneself and others. Yet most evaluations stop at explicit belief attribution in classical toy stories or stylized tasks, leaving open the questions of whether LLMs can implic…

Cited by 0SourcecodeScholar
2025

Answer, Assemble, Ace: Understanding How LMs Answer Multiple Choice Questions

ICLR 2025spotlight

Multiple-choice question answering (MCQA) is a key competence of performant transformer language models that is tested by mainstream benchmarks. However, recent evidence shows that models can have quite a range of performance, particularly when the task format is diversified slightly (such as by shu…

Cited by 0SourcePDFScholar
2025

CodeScientist: End-to-End Semi-Automated Scientific Discovery with Code-based Experimentation

ACL 2025finding

Despite the surge of interest in autonomous scientific discovery (ASD) of software artifacts (e.g., improved ML algorithms), current ASD systems face two key limitations: (1) they largely explore variants of existing codebases or similarly constrained design spaces, and (2) they produce large volume…

2025

DataDecide: How to Predict Best Pretraining Data with Small Experiments

ICML 2025poster

Because large language models are expensive to pretrain on different datasets, using smaller-scale experiments to decide on data is crucial for reducing costs. Which benchmarks and methods of making decisions from observed performance at small scale most accurately predict the datasets that yield th…

Cited by 0SourcePDFScholar
2025

From Models to Microtheories: Distilling a Model's Topical Knowledge for Grounded Question-Answering

ICLR 2025poster

Recent reasoning methods (e.g., chain-of-thought) help users understand how language models (LMs) answer a single question, but they do little to reveal the LM’s overall understanding, or “theory,” about the question’s topic, making it still hard to trust the model. Our goal is to materialize such t…

2025

OLMES: A Standard for Language Model Evaluations

NAACL 2025findings

Progress in AI is often demonstrated by new models claiming improved performance on tasks measuring model capabilities. Evaluating language models can be particularly challenging, as choices of how a model is evaluated on a task can lead to large changes in measured performance. There is no common s…

2025

OLMoE: Open Mixture-of-Experts Language Models

ICLR 2025oral

We introduce OLMoE, a fully open, state-of-the-art language model leveraging sparse Mixture-of-Experts (MoE). OLMoE-1B-7B has 7 billion (B) parameters but uses only 1B per input token. We pretrain it on 5 trillion tokens and further adapt it to create OLMoE-1B-7B-Instruct. Our models outperform all…

2024

DiscoveryWorld: A Virtual Environment for Developing and Evaluating Automated Scientific Discovery Agents

NeurIPS 2024spotlight

Automated scientific discovery promises to accelerate progress across scientific domains, but evaluating an agent's capacity for end-to-end scientific reasoning is challenging as running real-world experiments is often prohibitively expensive or infeasible. In this work we introduce DiscoveryWorld,…

2024

Dolma: an Open Corpus of Three Trillion Tokens for Language Model Pretraining Research

ACL 2024long

Information about pretraining corpora used to train the current best-performing language models is seldom discussed: commercial models rarely detail their data, and even open models are often released without accompanying training data or recipes to reproduce them. As a result, it is challenging to…

2024

Enhancing Systematic Decompositional Natural Language Inference Using Informal Logic

EMNLP 2024main

Recent language models enable new opportunities for structured reasoning with text, such as the construction of intuitive, proof-like textual entailment trees without relying on brittle formal logic. However, progress in this direction has been hampered by a long-standing lack of a clear protocol fo…

Cited by 9SourcePDFScholar
2024

OLMo: Accelerating the Science of Language Models

ACL 2024long

Language models (LMs) have become ubiquitous in both NLP research and in commercial product offerings. As their commercial importance has surged, the most powerful models have become closed off, gated behind proprietary interfaces, with important details of their training data, architectures, and de…

2024

Paloma: A Benchmark for Evaluating Language Model Fit

NeurIPS 2024poster

Evaluations of language models (LMs) commonly report perplexity on monolithic data held out from training. Implicitly or explicitly, this data is composed of domains—varying distributions of language. We introduce Perplexity Analysis for Language Model Assessment (Paloma), a benchmark to measure LM…

Cited by 7SourcePDFScholar
2023

Increasing Probability Mass on Answer Choices Does Not Always Improve Accuracy

EMNLP 2023long main

When pretrained language models (LMs) are applied to discriminative tasks such as multiple-choice questions, they place probability mass on vocabulary tokens that aren't among the given answer choices. Spreading probability mass across multiple surface forms with identical meaning (such as "bath" an…

Cited by 0SourcecodeScholar
2023

Language Models with Rationality

EMNLP 2023long main

While large language models (LLMs) are proficient at question-answering (QA), it is not always clear how (or even if) an answer follows from their latent "beliefs". This lack of interpretability is a growing impediment to widespread use of LLMs. To address this, our goals are to make model beliefs a…

Cited by 0SourceScholar
2022

Entailer: Answering Questions with Faithful and Truthful Chains of Reasoning

EMNLP 2022main

Our goal is a question-answering (QA) system that can show how its answers are implied by its own internal beliefs via a systematic chain of reasoning. Such a capability would allow better understanding of why a model produced the answer it did. Our approach is to recursively combine a trained backw…

Cited by 58SourcePDFScholar
2022

LILA: A Unified Benchmark for Mathematical Reasoning

EMNLP 2022main

Mathematical reasoning skills are essential for general-purpose intelligentsystems to perform tasks from grocery shopping to climate modeling.Towards evaluating and improving AI systems in this domain, we proposeLILA, a unified mathematical reasoning benchmark consisting of 23 diversetasks along fou…

2022

Learn to Explain: Multimodal Reasoning via Thought Chains for Science Question Answering

NeurIPS 2022accept

When answering a question, humans utilize the information available across different modalities to synthesize a consistent and complete chain of thought (CoT). This process is normally a black box in the case of deep learning models like large-scale language models. Recently, science question benchm…

2022

Towards Teachable Reasoning Systems: Using a Dynamic Memory of User Feedback for Continual System Improvement

EMNLP 2022main

Our goal is a teachable reasoning system for question-answering (QA), where a user can interact with faithful answer explanations, and correct its errors so that the system improves over time. Our approach is to augment a QA model with a dynamic memory of user feedback, containing user-supplied corr…

Cited by 36SourcePDFScholar
2021

BeliefBank: Adding Memory to a Pre-Trained Language Model for a Systematic Notion of Belief

EMNLP 2021main

Although pretrained language models (PTLMs) contain significant amounts of world knowledge, they can still produce inconsistent answers to questions when probed, even after specialized training. As a result, it can be hard to identify what the model actually “believes” about the world, making it sus…

Cited by 53SourcePDFScholar
2021

Explaining Answers with Entailment Trees

EMNLP 2021main

Our goal, in the context of open-domain textual question-answering (QA), is to explain answers by showing the line of reasoning from what is known to the answer, rather than simply showing a fragment of textual evidence (a “rationale”). If this could be done, new opportunities for understanding and…

2021

“Let Your Characters Tell Their Story”: A Dataset for Character-Centric Narrative Understanding

EMNLP 2021finding

When reading a literary piece, readers often make inferences about various characters’ roles, personalities, relationships, intents, actions, etc. While humans can readily draw upon their past experiences to build such a character-centric view of the narrative, understanding characters in narratives…

2020

Leap-Of-Thought: Teaching Pre-Trained Models to Systematically Reason Over Implicit Knowledge

NeurIPS 2020spotlight

To what extent can a neural network systematically reason over symbolic facts? Evidence suggests that large pre-trained language models (LMs) acquire some reasoning capacity, but this ability is difficult to control. Recently, it has been shown that Transformer-based models succeed in consistent re…