arXiv Computation and Language

Instruction-Tuned Models Locally Produce More Syntactic Overlap -- But Not More Conditional Reuse -- Than Humans Do

The study examines whether large language models (LLMs) show syntactic convergence with human users by analyzing turn‑adjacent reuse of context‑free grammar (CFG) rules in 1,901 matched positions across sixteen open‑weight Llama and Gemma models. All models exhibited greater CFG‑rule overlap with the preceding human turn than with unrelated primes, especially for lower‑frequency rules, and instruction‑tuned models showed even higher overlap with the actual prime than the human responses they replaced. However, instruction tuning also increased overlap with unrelated primes, reduced the actual‑versus‑random difference, and lowered conditional rule‑reuse odds when controlling for rule‑set size, while consistently producing responses with higher lexical and semantic similarity to the preceding turn.

arXiv Computation and Language
Oct 22

Why is AI-generated language so hard to understand?

The paper investigates why AI-generated text has become harder to understand, focusing on psycholinguistic features linked to human processing difficulty such as object relative clauses, long syntactic dependencies, and low-frequency n-grams. Using a new corpus of AI-generated text from diverse domains, the study finds that frontier and near-frontier language models employ these difficult features more frequently than paraphrases from round-trip translation and human writing, including more inanimate subjects with animate verbs, longer dependencies, stacked nouns, and reduced object relatives. The authors hypothesize that AI models prioritize information density for tasks like math, code, and reasoning, diverging from human communication goals, and demonstrate this by fine‑tuning a model with a length penalty, which reduces human‑like linguistic behavior.

By Thomas Hikaru Clark, Matias B. Martin, Kyle Mahowald
arXiv AI
6d ago

From Geometry to Behavior: How Instruction Exposure Unlocks Latent Rhetorical Directions in LLMs

The paper investigates whether language models possess latent rhetorical abilities, specifically analogy reasoning, before instruction tuning. By extracting an "Analogy Vector" from the residual stream, the authors demonstrate that this vector can steer explanation style across several instruction-tuned models, improving performance metrics. Their findings reveal a continuous gradient of behavioral accessibility tied to the amount of instruction exposure during training, challenging the binary base‑vs‑instruct distinction and suggesting that instruction exposure shapes rhetorical knowledge in activation space.

By Shengjie Xu
arXiv Computation and Language
Aug 31

Diverging Transformer Predictions for Human Sentence Processing: A Comprehensive Analysis of Agreement Attraction Effects

The study evaluates eleven autoregressive transformer models on English agreement attraction scenarios using a surprisal-based approach. Results show that while transformers match human reading times for prepositional phrase configurations, they perform poorly on object‑extracted relative clauses, with predictions diverging across models and failing to capture human interference patterns. The authors argue that current transformers cannot adequately model human morphosyntactic processing and call for more rigorous, comprehensive testing to avoid misleading conclusions from limited syntactic setups.

By Titus von der Malsburg, Sebastian Pad\'o
arXiv Computation and Language
Oct 12

Not Just an Evaluation: A Case Study of Discourse Particle Sensitivity in Language Models

The paper studies how large language models (LLMs) handle the discourse particles "just" and "only" in natural conversation. Behavioral experiments show that both humans and LLMs prefer these particles and are more sensitive to "just" than "only", while instruction tuning enhances this sensitivity. Mechanistic analysis identifies specific units in the models that respond to each particle, revealing an asymmetric overlap in their internal representations.

By William Sheffield, Jiahui Chen, Amy Zhang, Alex Warstadt, Junyi Jessy Li, Kanishka Misra
arXiv AI
Jul 7

The Rise of Verbal Tics in Large Language Models: A Systematic Analysis Across Frontier Models

arXiv:2604. 19139v3 Announce Type: replace-cross Abstract: As Large Language Models (LLMs) continue to evolve through alignment techniques such as Reinforcement Learning from Human Feedback (RLHF) and Constitutional AI, a growing and increasingly conspicuous phenomenon has emerged: the proliferation of verbal tics--repetitive, formulaic linguistic patterns that pervade model outputs.

By Shuai Wu, Xue Li, Yanna Feng, Yufang Li, Zhijun Wang, Ran Wang
arXiv AI
Oct 9

Imperative Interference: Social Register Shapes Instruction Topology in Large Language Models

The paper investigates how the imperative mood in system prompt instructions influences instruction topology across languages. Experiments on four languages and four models show that imperative instructions can invert cooperative and competitive interaction patterns, and that rewriting these instructions to declarative form reduces cross‑linguistic variance by 81%. The study suggests that language‑dependent social register shapes how large language models interpret instructions, implying that imperative‑mood directives may lead to language‑specific alignment during training and inference.

By Tony Mason
arXiv AI
Sep 12

How LLMs Follow Instructions: Skillful Coordination, Not a Universal Mechanism

Instruction tuning is often thought to give language models a universal ability to follow instructions, but this study shows otherwise. By probing nine tasks across three models, the authors find that general probes reveal selective, not uniform, deficits, cross‑task transfer is weak and skill‑similar, and causal ablation uncovers sparse, asymmetric dependencies. The results suggest instruction following is a coordinated use of diverse linguistic skills rather than a single shared mechanism.

By Elisabetta Rocchetti, Alfio Ferrara
arXiv AI
Sep 2

Do as I Say, Not as I Do: Instruction-Induction Conflict in LLMs

The paper investigates how large language models balance instruction-following with pattern completion when the two objectives conflict. By creating dialogues where a user instruction to act in a target way T is opposed by assistant turns that demonstrate a competing pattern P, the authors measure instruction-following rates across 13 models and 16 instructions over up to 50 turns. Results show wide variability (1%–99%) in instruction adherence, with robustness influenced by instruction content, output format, and chain-of-thought reasoning, but overall instruction-following remains brittle under induction pressure.

By Carolina Camassa, Derek Shiller
arXiv Computation and Language
Sep 1

How Human-Like Are Large Language Models? A Register-Aware Linguistic Evaluation Framework

The paper introduces a register-aware framework to evaluate how human-like large language models (LLMs) are, focusing on linguistic feature distributions rather than factual correctness. It uses Maximum Mean Discrepancy (MMD) and 67 Biber lexico‑grammatical features to compare LLM‑generated texts with human reference corpora across different registers. Experiments on seven instruction‑tuned, open‑source models across five English datasets show that all LLMs deviate from human baselines, with closeness to human language varying by register and not by model size.

By Bj\"orn Nieth, Marianna Gracheva, Michaela Mahlberg, Bjoern Eskofier, Emmanuelle Salin