RippleMem: From Isolated Retrieval to Associative Recollection for Long-Term Agent Memory

AuthorsJingbo Ji, Lingyi Li, Xilong Cheng et al.

arXiv 20262026

TL;DR

RippleMem uses cue-rich episodic memory units plus anchor-local associative recollection to reach 87.14% judge accuracy on LoCoMo, +3.31 points over RF-Mem.

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THE PROBLEM

Evidence is stored but not recollected together

RippleMem highlights that answer-critical evidence can be stored yet missed, as flat retrieval returns isolated records and undirected association surfaces non-supporting memories.

In long-horizon conversational agents, this causes queries that depend on distributed events, preferences, or constraints to be answered incorrectly despite the relevant history being present.

HOW IT WORKS

RippleMem: Event-Centric Memory with Associative Recollection

RippleMem’s core mechanism combines Cue-Rich Episodic Memory Construction, an Event-Centric Memory Graph, Adaptive Associative Recollection, and Evidence Assembly to turn dialogue into cue-rich event memories.

You can think of RippleMem like a hippocampus-backed card catalog: events are indexed by semantic vectors and episodic cues, then recalled and expanded from anchors when partial evidence is found.

This associative recollection lets RippleMem recover missing support across sessions and time, something a plain context window or one-shot RAG cannot reliably achieve.

DIAGRAM

RippleMem Query-Time Recollection Flow

This diagram shows how RippleMem processes a query through hybrid initial recall, anchor planning, graph expansion, and evidence assembly during inference.

DIAGRAM

RippleMem Evaluation and Ablation Pipeline

This diagram shows how RippleMem is evaluated on LoCoMo and LongMemEval-S, including baselines and ablation variants.

PROCESS

How RippleMem Handles a Long-Horizon Query

  1. 01

    Cue-Rich Episodic Memory Construction

    RippleMem processes dialogue windows into schema-guided memory units with restatements, dense vectors, and episodic cues Pi, Li, Ti, ensuring each event is independently retrievable.

  2. 02

    Event-Centric Memory Graph

    RippleMem links memory units into a sparse weighted event graph using semantic association ssem and structural association sstr over participants, locations, and temporal intervals.

  3. 03

    Adaptive Associative Recollection

    Given a query, RippleMem performs hybrid initial recall, then uses a recollection controller to select anchors Ar and missing-support target gr, expanding locally in the graph to recover support Sr.

  4. 04

    Evidence Assembly

    RippleMem consolidates provenance, scores memories with ρ(m) combining alignment and anchor status, selects top K units as EK, and passes them to the answer generator for grounded responses.

KEY CONTRIBUTIONS

Key Contributions

  • 01

    Evidence Recovery Formulation for Long-Term Memory

    RippleMem frames long-term memory as recovering an answerable evidence set from distributed traces, highlighting that one-shot query matching can miss stored support across interactions.

  • 02

    RippleMem Event-Centric Associative Recollection

    RippleMem combines Cue-Rich Episodic Memory Construction, an Event-Centric Memory Graph, and Adaptive Associative Recollection so recalled memories act as both context and cues for further support.

  • 03

    Benchmark Gains with 30× Cheaper Graph Construction

    RippleMem achieves 87.14% judge accuracy on LoCoMo and up to 86.60% on LongMemEval-S, while reducing graph construction time by about 30× compared with Zep on LoCoMo.

RESULTS

By the Numbers

LLM-as-a-Judge Accuracy

87.14%

+3.31 over RF-Mem on LoCoMo

F1

52.49

+1.01 over SimpleMem on LoCoMo

BLEU-1

44.05

+1.54 over SimpleMem on LoCoMo

LongMemEval-S Overall Accuracy

86.60%

+3.60 over EverMemOS in its evaluation setting

On LoCoMo, a long-term conversational memory benchmark, RippleMem’s 87.14% judge accuracy and 52.49 F1 show more complete evidence recovery than RF-Mem and SimpleMem. On LongMemEval-S, RippleMem’s 86.60% overall accuracy demonstrates strong multi-session reasoning and temporal tracking in full-history user agent interactions.

BENCHMARK

By the Numbers

On LoCoMo, a long-term conversational memory benchmark, RippleMem’s 87.14% judge accuracy and 52.49 F1 show more complete evidence recovery than RF-Mem and SimpleMem. On LongMemEval-S, RippleMem’s 86.60% overall accuracy demonstrates strong multi-session reasoning and temporal tracking in full-history user agent interactions.

BENCHMARK

LoCoMo Overall LLM-as-a-Judge Accuracy Comparison

LLM-as-a-Judge accuracy on LoCoMo across RippleMem and key baselines.

BENCHMARK

LongMemEval-S Overall Accuracy in EverMemOS Setting

Overall LLM-as-a-Judge accuracy on LongMemEval-S under the EverMemOS evaluation setting.

KEY INSIGHT

The Counterintuitive Finding

RippleMem cuts graph construction time on LoCoMo from 3532.03 seconds for Zep to 117.51 seconds, roughly a 30× reduction while increasing judge accuracy from 76.69 to 87.14.

This is counterintuitive because richer associative recollection and event graphs usually seem more expensive, yet RippleMem’s sparse, incremental design yields both higher accuracy and dramatically lower construction cost.

WHY IT MATTERS

What this unlocks for the field

RippleMem unlocks long-term agents that can treat initial recall as a starting point, using anchors and episodic cues to complete missing evidence across sessions and timelines.

Builders can now design memory systems where stored experience is organized into cue-rich events and recollection is guided by evidence needs, making reliable long-horizon reasoning practical without massive context windows.

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