H2HMem: A Multimodal Memory Benchmark for Agents in Human-Human Interactions

AuthorsShiping Zhu, Yibo Yang, Zhengyang Wang et al.

arXiv 20262026

TL;DR

H2HMem uses a human-in-the-loop multimodal dialogue pipeline plus a 9-task memory taxonomy to show best methods reach only 0.5757 overall LLM-as-Judge score.

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THE PROBLEM

Multimodal human conversations break existing memory benchmarks (no benchmark covers dyadic, multi-party, and multimodal together)

Existing memory benchmarks are single-user, text-only, and human–assistant focused, missing multimodal, multi-party human–human interactions.

In these settings, agents must resolve anaphora, deixis, and conflicting participant information across sessions, but current evaluations cannot expose these failures.

HOW IT WORKS

H2HMem — a multimodal human–human memory benchmark

H2HMem builds on Participant Profile Generation, Scenario Construction, Image Collection and Human Refinement, Image Captioning and Dialogue Generation, and Question-Answer Pairs Construction to create realistic multimodal dialogues.

Think of H2HMem like a scripted TV series: profiles define recurring characters, scenarios outline episodes, images set scenes, and QA tasks quiz long-term plot understanding.

This design lets H2HMem probe memory behaviors—recall, reasoning, and application—far beyond what a plain context window or simple RAG setup can test.

DIAGRAM

Memory-based QA flow in H2HMem

This diagram shows how H2HMem feeds multi-session multimodal dialogues into agents that store memories, retrieve them, and answer benchmark questions.

DIAGRAM

H2HMem dataset construction pipeline

This diagram visualizes the five-stage human-in-the-loop pipeline H2HMem uses to build multimodal dyadic and multi-party conversations.

PROCESS

How H2HMem Handles a Multi-session Memory QA Task

  1. 01

    Participant Profile Generation

    H2HMem first runs Participant Profile Generation to create structured personas that drive consistent behavior across sessions and anchor memory cues.

  2. 02

    Scenario Construction

    Next, Scenario Construction uses these profiles to sample topics and generate multi-session outlines plus image keywords that distribute facts over time.

  3. 03

    Image Collection and Human Refinement

    Image Collection and Human Refinement aligns retrieved or generated images with outlines, ensuring visual evidence supports later memory questions.

  4. 04

    Question-Answer Pairs Construction

    Finally, Question-Answer Pairs Construction targets recall, reasoning, and application, turning dialogues into graded memory tasks for H2HMem.

KEY CONTRIBUTIONS

Key Contributions

  • 01

    Human-to-Human Multimodal Memory Benchmark

    H2HMem defines a unified benchmark over dyadic and multi-party conversations, totaling 25 dialogues, 309 sessions, 7,078 rounds, and 1,300 images.

  • 02

    Human-in-the-loop Dataset Construction Pipeline

    H2HMem introduces a five-stage pipeline with Participant Profile Generation and Scenario Construction to safely synthesize realistic, privacy-preserving multimodal interactions.

  • 03

    Comprehensive Memory Evaluation Taxonomy

    H2HMem designs nine tasks across Memory Recall, Memory Reasoning, and Memory Application, yielding 2,236 QA pairs with 618 image-grounded questions.

RESULTS

By the Numbers

Overall LLM-as-Judge score

0.5757

+0.1188 over Full (Text) on H2HMem weighted D&M

Memory Recall LLM-as-Judge

0.6652

vs NaiveRAG 0.5181 on H2HMem recall tasks

Memory Reasoning LLM-as-Judge

0.4572

tests MCR, RET, TR difficulty on H2HMem

Memory Application LLM-as-Judge

0.6045

shows TTL, CD, AR remain challenging on H2HMem

On the H2HMem benchmark, GPT-4.1-Nano with A-Mem achieves an overall weighted LLM-as-Judge score of 0.5757 across recall, reasoning, and application tasks. This demonstrates that even advanced memory systems struggle to integrate multimodal, multi-participant information over long horizons.

BENCHMARK

By the Numbers

On the H2HMem benchmark, GPT-4.1-Nano with A-Mem achieves an overall weighted LLM-as-Judge score of 0.5757 across recall, reasoning, and application tasks. This demonstrates that even advanced memory systems struggle to integrate multimodal, multi-participant information over long horizons.

BENCHMARK

Weighted average (D&M) overall performance with GPT-4.1-Nano

LLM-as-Judge overall scores on H2HMem for different memory methods.

KEY INSIGHT

The Counterintuitive Finding

On H2HMem, the best overall LLM-as-Judge score is only 0.5757, even though A-Mem reaches 0.6652 on Memory Recall alone.

This is surprising because many assume better retrieval solves memory, but H2HMem shows reasoning and conflict handling remain weak despite strong recall.

WHY IT MATTERS

What this unlocks for the field

H2HMem gives researchers a controlled way to stress-test multimodal, multi-party memory across recall, reasoning, and application with realistic human–human dialogues.

With H2HMem, builders can now benchmark observer-style agents for meetings, clinics, and chats under conditions that were previously unmeasured and easy to overestimate.

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