PonsRAG: A Pons-Inspired RAG Bridging Cognitive Islands for Coordinated Long Narrative Reasoning
Organizations: School of Software Engineering, Sun Yat-sen University · School of Future Technology, South China University of Technology · TikTok Inc · School of Artificial Intelligence, Sun Yat-sen University
Abstract
Long Narrative Reasoning is an essential capability for processing and reasoning over complex narratives. While retrieval-augmented generation provides a promising framework, existing methods still face two critical challenges: cognitive islanding and cross-layer evidence disconnection. To address these issues, we propose PonsRAG, a coordinated RAG framework inspired by the biological pons. PonsRAG consists of two key components: Triple-Layer Indexing, which organizes documents into a connected knowledge structure to bridge cognitive islands, and Coordinated Reasoning, which retrieves evidence across distinct layers and integrates cross-layer information into a unified context. We evaluate PonsRAG on four long-context narrative benchmarks, and experimental results show that it outperforms the strongest baseline, achieving a 11.56% relative improvement in average accuracy on multi-choice tasks.
Figures & tables
| Method | NarrativeQA | EN.QA | EN.MC | NoCha | QA Avg. | MC Avg. | |||
|---|---|---|---|---|---|---|---|---|---|
| F1 | EM | F1 | EM | ACC | ACC | F1 | EM | ACC | |
| LLM | |||||||||
| GPT-4o-mini | 27.29 | 7.00 | 29.83 | 12.82 | 30.57 | 60.32 | 28.56 | 9.91 | 45.45 |
| Naive RAG | |||||||||
| BGE-M3(0.3B) | 23.16 | 15.10 | 23.71 | 16.24 | 59.82 | 56.35 | 23.44 | 15.67 | 58.09 |
| NV-Embed-v2 (7B) | 27.18 | 17.80 | 34.34 | 24.57 | 61.13 | 68.25 | 30.76 | 21.19 | 64.69 |
| Method | NarrativeQA | EN.QA | EN.MC | NoCha | QA Avg. | MC Avg. | |||
|---|---|---|---|---|---|---|---|---|---|
| F1 | EM | F1 | EM | ACC | ACC | F1 | EM | ACC | |
| IRCoT +RAPTOR | 31.35 | 16.00 | 32.09 | 19.36 | 63.76 | 57.94 | 31.72 | 17.68 | 60.85 |
| IRCoT +HippoRAGv2 | 28.98 | 13.00 | 29.27 | 18.24 | 64.19 | 61.90 | 29.13 | 15.62 | 63.05 |
| IRCoT +Youtu-GraphRAG | 25.92 | 15.40 | 31.10 | 22.79 | 66.38 | 63.49 | 28.51 | 19.10 | 64.94 |
| ComoRAG (five steps) | 31.43 | 18.60 | 34.52 | 25.07 | 72.93 | 61.90 | 32.98 | 21.84 | 67.42 |
| IRCoT+PonsRAG (Ours) | 33.28 | 20.60 | 36.30 | 26.78 | 79.48 | 72.22 | 34.79 | 23.69 | 75.85 |
| Method | EN.MC | EN.QA | |
|---|---|---|---|
| ACC | F1 | EM | |
| PonsRAG | 77.73 | 35.13 | 26.21 |
| Index | |||
| w/ Char | 52.40 | 21.73 | 17.95 |
| w/ Plot | 55.02 | 23.37 | 18.23 |
| w/o Pons | 61.13 | 28.59 | 19.37 |
| EN.MC (ACC) | EN.QA (F1) | |
|---|---|---|
| 0.00 | ||
| 0.25 | ||
| 0.50 | ||
| 0.75 | ||
| 0.80 | ||
| 0.90 |
| Matching Strategy | EN.MC (ACC) | EN.QA (F1) | Avg Context Tokens |
|---|---|---|---|
| Dense (w/o Match) | 68.12 | 28.65 | 5,203 |
| 1-to-3 | 73.03 | 30.34 | 3,856 |
| 1-to-2 | 74.24 | 32.28 | 2,438 |
| 1-to-1 (Ours) | 77.73 | 35.13 | 1,187 |
Appendix figures & tables8 assets
Supplementary material from the paper’s appendix.
Appendix
| Dataset | #Docs | #Queries | Total Tokens | Avg. Tokens |
|---|---|---|---|---|
| NarrativeQA | 17 | 500 | 887,763 | 52,221 |
| EN.QA | 69 | 351 | 14,497,149 | 210,104 |
| EN.MC | 58 | 229 | 11,249,572 | 193,958 |
| NoCha | 4 | 126 | 555,972 | 138,993 |
| Hyperparameter | Value |
|---|---|
| Model Selection | |
| LLM Backbone Agent | GPT-4o-mini |
| Retrieval Embedding Model | BGE-M3 |
| Triple-Layer Indexing Setup | |
| Max Chunk Size | 512 tokens |
| Sparsity Controller ( ) | 0.75 (MC) / 0.50 (QA) |
| MGS Configuration | EN.MC (ACC) | EN.QA (F1) |
|---|---|---|
| Bridging Scheme | Prec@100 | EN.MC | EN.QA |
|---|---|---|---|
| (ACC) | (F1) | ||
| Entity Mention | 91.0% | 58.45 | 24.82 |
| Pure Semantic | 64.0% | 68.12 | 30.95 |
| Pons Weight (Ours) | 82.0% | 75.54 | 34.56 |
| Query Type | EN.MC | EN.QA | Total | Proportion |
|---|---|---|---|---|
| Char | 59 | 114 | 173 | 29.8% |
| Plot | 68 | 86 | 154 | 26.6% |
| Mix | 102 | 151 | 253 | 43.6% |
| Total | 229 | 351 | 580 | 100.0% |
| Predicted (GPT-4o) | ||||
| True (Human) | Char | Plot | Mix | Total |
| Char | 25 | 3 | 1 | 29 |
| Plot | 1 | 22 | 3 | 26 |
| Mix | 0 | 4 | 41 | 45 |
| Accuracy | 88.0% | |||
| Metrics | PonsRAG | GraphRAG | HiRAG |
|---|---|---|---|
| Performance | |||
| F1 Score | 34.38 (100%) | 14.60 (42.5%) | 21.37 (62.2%) |
| EM Score | 25.31 (100%) | 8.20 (32.4%) | 14.28 (56.4%) |
| Token Usage | |||
| Tokens | 1.08M (100%) | 26.43M (2447%) | 95.81M (8871%) |
| Average Time (s) | |||
| Input Data (No Options) |
| Query: How does Jimmy Doyle spend all of his money with his friends in “After the Race”? |
| Options: [A] Betting on car racing [B] Playing cards [C] Arm wrestling [D] Treating his friends to drinks |
| PonsRAG’s Choice Result |
| Query Anchor |
| Anchor Char Nodes : |
| - JIMMY (PERSON) : Jimmy is the son of a wealthy butcher, educated in England and known for his popularity and social life… |
Retrieval-Augmented Generation
Retrieval-augmented generation connects language models to external knowledge so answers can use current, domain-specific evidence.
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