arXiv Computer Vision

Understanding Affective Adaptation in Multimodal Foundation Models: Emergent Functional Specialization

The paper investigates how affective fine‑tuning shapes the internal architecture of multimodal foundation models. By analyzing 13 model instances across nine designs, it finds that adapting the feed‑forward network (FFN) consistently outperforms attention‑only adaptation and nearly matches full‑model tuning, revealing the FFN as an efficient adaptation substrate. Moreover, joint optimization leads to emergent functional specialization, notably a prominent gate projection pathway, which the authors exploit in Gate‑Focused Efficient Tuning (GET) to achieve 96.2–98.0% of full‑model performance with only 19.3–24.5% of the trainable parameters.

arXiv AI
Sep 21

Decoupling Internal Representational Changes and Causal Importance in Fine-Tuned Large Language Models

Fine‑tuning reshapes internal representations of large language models, affecting attention patterns and layer‑wise activations. The study shows that components identified by EAP as important for task performance cluster in specific layers, yet these layers do not align with those undergoing the largest representational changes. Additionally, overlapping EAP components across different tasks do not guarantee cross‑task transfer and can even degrade performance when tasks differ in nature.

By Lingfang Li, Procheta Sen, Shubham Das, Danushka Bollegala
arXiv AI
Jun 2

When Do Attention Circuits Form? Developmental Trajectories of Capability and Attention-Sink Emergence Across Three 1B-ClassArchitectures

arXiv:2606. 02378v1 Announce Type: cross Abstract: We track the developmental trajectory of attention-head circuit formation across three 1B-class language models spanning two architecture families (dense transformer, mixture-of-experts) and two pretraining corpora (The Pile, DCLM): Pythia 1B, OLMo 1B-0724-hf, and OLMoE 1B-7B-0924.

By Yongzhong Xu
arXiv Machine Learning
Sep 4

Modern Transformers Are Implicit Hybrids: From Functional Differentiation to Principled Hybrid Architecture Design

The paper proposes a principled way to design hybrid transformer architectures that combine Full Attention (FA) and Linear Attention (LA). By introducing two intervention metrics—RoPE Frequency Importance Score (RFIS) and RoPE Positional Dependence (RPD)—the authors identify a clear taxonomy of retrieval and positional heads, defining a Global Positional Band (GPBand) that aligns with training-length positional scales. Using these insights, they build a Head‑wise Hybrid Architecture (HwH) that assigns FA to global retrieval and LA to local positional modeling, achieving strong language modeling, improved retrieval, and superior zero‑shot long‑context extrapolation compared to standard Transformers and other hybrids.

By Runlin Shi, Bojian Yin, Guoqi Li
arXiv AI
Sep 17

Structure is not mechanism: high-gain gated-FFN rows across text and genomic foundation models

The study investigates whether unusually high‑gain parameters in transformer models—specifically gated feed‑forward network (gated‑FFN) rows—play a critical functional role across both text and genomic foundation models. By computing exact bilinear weight operators and testing structural extremeness, the authors find that high‑gain rows are enriched for functional importance but do not reliably predict causal effect size or severity. The analysis reveals model‑specific causal organizations, including super‑additive interactions in DNABERT‑2 and position‑localized dependencies in GENERator, indicating that structural prominence signals enrichment rather than calibrated criticality.

By Alexandros Tzanakakis, Aris Karatzikos, Ilias Georgakopoulos-Soares
arXiv AI
Aug 11

Emotion2Skill: Model-Internal Emotion Signals for Adaptive Skill Selection and Evolution

arXiv:2608. 09248v1 Announce Type: new Abstract: Skill-based LLM agents select reusable procedures from an external library to solve complex tasks, yet their routing decisions rely entirely on text-level signals such as task descriptions, verbal reflections, and experience-derived rules, while the model's own internal representational state remains unobserved.

By Bohan Lin, Hejia Geng, Xinyi Xie, Heng Zhou, Qinghua Xing, Bo Liu, Chen Zhang, Yudong Zhang
arXiv AI
Aug 13

Conflict and Congruency Effects in Large Language Models: In-Weight and In-Context Competition in a Verbal Conflict Task

arXiv:2608. 11510v1 Announce Type: cross Abstract: Congruency effects, observed in conflict tasks such as Stroop and flanker tasks, have been investigated for nearly a century in psychology and neuroscience, but their mechanistic basis is not fully understood.

By Xiaoyang Hu, Mike Angstadt, Shane Storks, Zan Huang, Aman Taxali, Alex Weigard, Richard L. Lewis, Chandra Sripada