Add model card README

README.md

@@ -0,0 +1,91 @@
+---
+license: apache-2.0
+base_model:
+- Qwen/Qwen3-VL-8B-Instruct
+pipeline_tag: text-generation
+library_name: transformers
+tags:
+- human-simulation
+- role-play
+- social-intelligence
+---
+
+# Ditto-8B
+
+**Ditto-8B** is an 8B open-weight model for **human behavior simulation**, covering theory of
+mind, character role-play, social skills, learner simulation, user simulation, and persona
+simulation.
+
+- 📄 Paper: [Reinforcing Human Behavior Simulation via Verbal Feedback](https://arxiv.org/abs/2605.20506)
+- 💻 Code: https://github.com/sunnweiwei/OdysSim
+- 📊 Data (SOUL): https://huggingface.co/datasets/sunweiwei/Soul
+
+## Method
+
+Ditto-8B is trained with **DITTO**, a reinforcement learning method that uses **verbal
+feedback** as the learning signal. After each output, the model receives descriptive feedback
+and produces an improved version; both are jointly optimized with GRPO. This distills the
+verbal guidance into the policy, so **no feedback is needed at inference time**.
+
+## Results
+
+Primary metric for each benchmark (higher is better).
+
+| Dim | Benchmark | GPT 5.5 | Gemini 3.1 Pro | Claude Opus 4.7 | Qwen 3.6 Plus | Others* | Qwen3 8B Inst | Ditto-8B |
+|---|---|---|---|---|---|---|---|---|
+| CONV | UserLLM | 65.3 | 67.7 | 57.6 | 72.1 | 44.6 | 46.0 | 91.5 |
+| CONV | MirrorBench | 56.7 | 48.3 | 63.7 | 48.0 | 45.4 | 54.0 | 73.4 |
+| CONV | Humanual-Chat | 28.2 | 21.0 | 22.6 | 22.2 | 25.8 | 24.7 | 21.0 |
+| CONV | SimArena-Doc | 83.4 | 83.0 | 83.5 | 82.4 | 83.5 | 83.6 | 84.4 |
+| SS | Sotopia-Hard | 31.9 | 27.8 | 32.4 | 28.3 | 31.7 | 27.7 | 45.8 |
+| COG | Fantom | 93.0 | 93.0 | 80.0 | 89.0 | 70.0 | 23.0 | 92.0 |
+| COG | Hitom | 82.0 | 86.0 | 93.0 | 73.0 | 56.0 | 62.0 | 79.0 |
+| COG | Paratomi | 99.0 | 97.0 | 90.0 | 94.0 | 75.0 | 67.0 | 95.0 |
+| COG | Social-R1 | 69.0 | 79.0 | 67.0 | 67.0 | 47.0 | 54.0 | 50.0 |
+| ROLE | Coser | 66.2 | 62.1 | 66.5 | 55.9 | 30.3 | 43.5 | 64.4 |
+| ROLE | Lifechoices | 91.0 | 84.0 | 92.0 | 79.0 | 67.0 | 70.0 | 70.0 |
+| ROLE | Twinvoice | 74.0 | 86.0 | 83.0 | 71.0 | 40.0 | 42.0 | 71.0 |
+| ROLE | BehaviorChain | 95.0 | 92.0 | 96.0 | 85.0 | 36.0 | 41.0 | 44.0 |
+| ROLE | SimArena-Math | 68.5 | 71.5 | 68.7 | 70.9 | 70.5 | 68.9 | 69.6 |
+| ROLE | Mistakes | 72.0 | 73.0 | 74.0 | 67.0 | 56.0 | 27.0 | 36.0 |
+| ROLE | Humanual-Email | 50.1 | 46.9 | 50.4 | 47.9 | 42.8 | 43.7 | 40.8 |
+| ROLE | Humanual-News | 40.2 | 42.3 | 41.3 | 41.8 | 33.1 | 32.5 | 27.5 |
+| ROLE | Humanual-Politics | 42.0 | 32.5 | 43.5 | 31.6 | 34.2 | 33.2 | 29.7 |
+| EVAL | AlignX | 71.2 | 73.4 | 71.6 | 69.8 | 66.8 | 68.6 | 67.4 |
+| EVAL | Humanllm | 45.7 | 46.9 | 44.2 | 42.7 | 35.2 | 34.1 | 33.1 |
+| EVAL | Socsci210 | 77.2 | 78.0 | 77.2 | 74.5 | 75.2 | 73.6 | 72.5 |
+| EVAL | Humanual-Book | 57.6 | 62.4 | 61.4 | 58.4 | 50.2 | 53.6 | 53.4 |
+| EVAL | Humanual-Opinion | 39.8 | 36.0 | 46.2 | 34.2 | 37.4 | 37.2 | 30.3 |
+
+\* *Others*: best result among other specialized human-simulation models (HumanLM-8B, Sotopia-RL-7B, UserLM-8B, Coser-8B).
+
+> **Note.** The released Ditto-8B is a single generalist distilled from a set of task-specific DITTO experts via rejection sampling on the training set.
+
+## Usage
+
+```python
+from transformers import AutoModelForCausalLM, AutoTokenizer
+
+model_name = "sunweiwei/Ditto-8B"
+tokenizer = AutoTokenizer.from_pretrained(model_name)
+model = AutoModelForCausalLM.from_pretrained(model_name, torch_dtype="auto", device_map="auto")
+
+messages = [{"role": "user", "content": "Hello!"}]
+text = tokenizer.apply_chat_template(messages, tokenize=False, add_generation_prompt=True)
+inputs = tokenizer(text, return_tensors="pt").to(model.device)
+outputs = model.generate(**inputs, max_new_tokens=512)
+print(tokenizer.decode(outputs[0][inputs.input_ids.shape[1]:], skip_special_tokens=True))
+```
+
+## Citation
+
+```bibtex
+@article{sun2026ditto,
+  title         = {Reinforcing Human Behavior Simulation via Verbal Feedback},
+  author        = {Sun, Weiwei and Zhou, Xuhui and Liu, Jiarui and Du, Weihua and Sun, Haojia and Xie, Yiqing and Ma, Qianou and Chen, Sihao and Wan, Mengting and Yang, Longqi and Zhou, Pei and Wu, Sherry and Welleck, Sean and Neubig, Graham and Yang, Yiming and Sap, Maarten},
+  year          = {2026},
+  eprint        = {2605.20506},
+  archivePrefix = {arXiv},
+  url           = {http://arxiv.org/abs/2605.20506}
+}
+```