Multimodal Chain-of-Thought Reasoning Framework: Making AI's Reasoning Process Interpretable and Verifiable

This project proposes a unified multimodal Chain-of-Thought (CoT) reasoning framework, integrating large language models (LLMs), context-guided prompts, few-shot reasoning, and probabilistic answer verification. It aims to solve the reasoning black-box problem of multimodal AI and achieve interpretable and verifiable reasoning evaluation across ScienceQA and A-OKVQA datasets. The framework transparently presents the reasoning process through a structured pipeline, balancing performance and interpretability, and provides a technical solution for trustworthy multimodal AI systems.

As LLMs improve their performance in multimodal tasks such as visual question answering and scientific reasoning, the reasoning black-box problem has become increasingly prominent: the internal processes of traditional end-to-end models are incomprehensible. In ScienceQA (scientific question answering) and A-OKVQA (open-world visual question answering), there are four major challenges: whether the model understands the question, whether visual information is correctly utilized, whether there are logical loopholes in the reasoning path, and whether the answer is consistent with the reasoning. Therefore, this project proposes a unified multimodal CoT framework to transform reasoning from a black box to a white box.

The framework adopts a six-stage reasoning pipeline:

1. Input problem parsing: Multimodal encoding of text (questions, options, background) and visual (images, charts) information;
2. Context integration: Fine-grained identification of key entities, extraction of visual regions, and establishment of text-visual correspondence;
3. Few-shot prompt construction: Dynamically retrieve similar examples (question-reasoning-answer triples) to generate guiding prompts;
4. LLM reasoning generation: Step-by-step decomposition of the problem, generating natural language reasoning with intermediate conclusions and evidence citations;
5. Probabilistic selection verification: Calculate option probability scores, sort them, and estimate confidence;
6. Reasoning consistency verification: Check the consistency between explanation and answer, logical contradictions, modal alignment, etc. If inconsistent, re-reason or conduct manual review.

Key technical components include: heuristic confidence scoring (integrating reasoning completeness, evidence sufficiency, etc.), reasoning consistency verifier (checking logic, evidence, modality, answer consistency), and interpretability visualization tools (accuracy curves, heatmaps, ring charts, etc.).

The framework verifies its cross-domain generalization ability on two representative datasets:

• ScienceQA: Covers disciplines such as physics and chemistry, requiring the combination of scientific knowledge and image understanding, with diverse question types (multiple choice, judgment), emphasizing reasoning interpretability;
• A-OKVQA: Focuses on open-world knowledge, requiring external common-sense reasoning, with flexible answer forms.

Through validation on both datasets, it is proven that the framework is applicable to multimodal question answering tasks with different characteristics.

Practical Significance:

• AI Research: Promote the progress of interpretable AI, establish multimodal reasoning evaluation standards, and provide model error diagnosis tools;
• Practical Applications: Interpretable scientific question answering systems in the education field help students understand thinking processes; medical diagnosis aids safe deployment; content review identifies AI biases; scientific research assists literature analysis and hypothesis verification.

Technical Insights: Improving interpretability does not require sacrificing performance; structured pipelines can balance model performance and transparency.

Future research directions include:

1. Expand to more modalities (audio, video, sensor data);
2. Develop adaptive few-shot example selection strategies;
3. Establish automatic evaluation metrics for reasoning quality;
4. Explore human-machine collaborative interactive reasoning modes.