Proteus: Incremental Memory Activation for Long-Context Sequence Modeling
Abstract: The quadratic cost of attention-based sequence models for long contexts has motivated a growing line of research on memory-based models that can compress context into a compact state. However, most existing memory models expose a static memory throughout the entire sequence. Because early tokens face no compression pressure, they occupy too many degrees of freedom and "pollute" the memory state, leaving little capacity for later context and increasing interference between what is stored and what arrives next. We study a new paradigm of incremental memory activation, where the effective capacity of memory is progressively expanded as the context grows. Imposing an early bottleneck forces the model to compress history more effectively, while unlocking fresh capacity over time reduces interference and improves retention of later context. We instantiate this paradigm in Proteus, a straightforward mechanism that can be incorporated into a broad class of neural memory architectures at no additional cost. We apply Proteus to state-of-the-art models, including SWLA, Comba, Titans, and Hope-Attention, and observe consistent improvements on standard language modeling and reasoning, as well as on long-context retrieval and understanding, with gains that grow at longer context lengths. Overall, our results show that static memory is suboptimal and that scheduling effective capacity is a simple and broadly applicable tool for sequence modeling.
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1. What is this paper about?
This paper introduces Proteus, a way to help AI models remember information from very long pieces of text.
Many LLMs, such as chatbots, need to read long conversations, books, or documents. The problem is that remembering everything can be expensive and difficult. Some models use a small, fixed-size memory to save computer power, but this memory can become crowded and forget important information.
Proteus tries to solve this by making the model’s memory available little by little instead of all at once.
2. What questions are the researchers asking?
The researchers focus on several main questions:
- Why do memory-based LLMs struggle with very long text?
- Does giving a model access to all of its memory from the beginning cause problems?
- Would it help to start with a small amount of memory and gradually activate more?
- Can this idea improve language understanding, reasoning, and information retrieval without adding extra parameters or computer memory?
The paper’s main idea is that memory should not always have a fixed amount of usable space. Instead, its usable capacity should change as more text arrives.
3. How does the method work?
The problem with regular memory
Imagine giving a student a large notebook at the beginning of a school year. If the student has plenty of empty pages, they might write down every small detail from the first few lessons.
Later, when the important lessons arrive, the notebook may be full. The student must erase or overwrite earlier notes to make room. This can cause confusion and loss of information.
Memory-based AI models can behave in a similar way:
- Early words can use too much memory because the memory is still empty.
- Later words have to compete for space.
- New information may overwrite or interfere with older information.
- The model may remember the beginning of a text better than the end.
Proteus’s solution
Proteus divides the model’s memory into several blocks, like dividing a notebook into sections.
At the beginning:
- Only a small number of blocks are active.
- The model must summarize the early text instead of storing every detail.
As the text continues:
- More blocks are unlocked.
- Later information gets fresh space.
- The model is less likely to overwrite what it already remembered.
The memory itself does not grow larger. The model simply decides which parts of its existing memory can be used at each point.
A simple example might look like this:
| Position in the text | Memory available |
|---|---|
| Beginning | 1 out of 16 blocks |
| Early-middle | 4 out of 16 blocks |
| Middle | 8 out of 16 blocks |
| Near the end | 12 out of 16 blocks |
| End of the training window | All 16 blocks |
The researchers call this incremental memory activation. “Incremental” means something happens gradually, step by step.
Proteus controls both:
- Writing: which memory blocks can store new information.
- Reading: which memory blocks the model can use when answering.
The method can be added to several different model designs, including SWLA, Comba, Titans, and Hope-Attention. It does not require extra model parameters or extra memory.
4. What experiments did the researchers perform?
The researchers tested models with and without Proteus.
They trained models on large amounts of Internet text using an 8,000-token context window. A token is a small piece of text, such as a word or part of a word.
They tested two model sizes:
- About 760 million parameters
- About 1.3 billion parameters
A parameter is a number inside an AI model that helps it learn patterns.
The tests measured several abilities:
- Language modeling: predicting the next word.
- Perplexity: how surprised the model is by the correct next word. Lower is better.
- Common-sense reasoning: answering questions about everyday situations.
- Needle-in-a-haystack retrieval: finding one important piece of information hidden inside a very long text.
- Long-context understanding: answering questions that require remembering information from long documents.
The researchers also tested texts up to 16,000 tokens long, which is longer than the 8,000-token length used during training.
5. What did they find?
Better general language performance
Adding Proteus generally improved the models’ language prediction and reasoning abilities.
For example, in the larger model experiments:
- Titans’ average reasoning score increased from 56.95 to 58.00.
- Its Wikitext perplexity improved from 15.36 to 14.94.
- Its LAMBADA perplexity improved from 13.18 to 13.03.
These changes may seem small, but they are meaningful because the models already performed well before Proteus was added.
Proteus improved all four main model families tested:
- Hope-Attention
- SWLA
- Comba
- Titans
Stronger long-context memory
The biggest improvements appeared when the text became longer.
For example, on a difficult needle-in-a-haystack task at 16,000 tokens:
- Titans improved from 21.4% to 29.8%.
- Comba improved from 13.4% to 21.2%.
This means Proteus helped the models find important information hidden deep inside long texts.
Proteus also improved performance on tasks involving:
- Multiple hidden facts
- Several questions about the same document
- Multiple pieces of information that had to be remembered together
More reliable performance beyond the training length
The models were trained with 8,000-token contexts but were tested with contexts up to 16,000 tokens.
Proteus often helped the models lose less accuracy as the text got longer. This suggests that the early memory bottleneck helped the model create a cleaner, more useful summary of the beginning of the text.
No extra memory or parameters
One especially important result is that Proteus improved performance without making the model larger.
It changes how the model uses its memory rather than simply giving it more memory. This could make it a practical improvement for existing AI systems.
6. Why are these results important?
Long-context understanding is important for many real-world uses, such as:
- Reading long research papers
- Summarizing books and reports
- Remembering earlier parts of a conversation
- Searching legal or medical documents
- Finding facts in large databases
- Analyzing long computer programs
A model that remembers only the beginning of a document may miss crucial information later. Proteus provides a simple way to make memory use more balanced.
The paper also challenges the idea that a model should use all of its memory equally from the start. The researchers argue that memory should be carefully scheduled:
- Less space early encourages useful summarizing.
- More space later protects new information from being overwritten.
7. What could this lead to?
Proteus could be added to many memory-based LLMs to improve their ability to handle long texts. Since it requires no additional parameters or memory, it may be cheaper than simply building a much larger model.
The idea might also be useful beyond text. Similar strategies could help AI systems process:
- Long videos
- Audio recordings
- Computer code
- Continuous streams of sensor data
However, the current method uses a fixed schedule based only on the position in the text. It does not decide based on how important or surprising each piece of information is.
Future versions might use adaptive activation, where the model opens more memory when it encounters especially important information. For now, the paper’s main lesson is simple:
A model may remember long contexts better if it starts with a small memory bottleneck and gradually unlocks more memory as the context grows.
Knowledge Gaps
Knowledge gaps, limitations, and open questions
- The paper does not provide a formal theoretical analysis showing when incremental activation should outperform static memory, or how the optimal schedule depends on sequence length, memory size, update rule, or data distribution.
- The claimed mechanisms—early compression, reduced interference, and improved retention of later context—are not directly measured using memory-state diagnostics, information-retention metrics, overwrite rates, or token-position-specific probing.
- The benefit of incremental activation is confounded with the use of a particular prefix-based, uniformly growing schedule; comparisons against constant-capacity, decreasing, nonlinear, randomized, and equal-average-capacity schedules are not reported in the provided text.
- The paper does not establish whether the gains arise from the early bottleneck, the later fresh capacity, or their combination; factorial ablations that independently remove or vary these two components are needed.
- Although the experiments state that the number of blocks is ablated, the ablation results are not included in the provided paper, leaving the sensitivity to block count unresolved.
- The effects of block granularity and partition structure are unexplored: contiguous prefix blocks may behave differently from interleaved, learned, row-wise, column-wise, or layer-specific partitions.
- The schedule is fixed using the 8K training length, but the paper does not systematically evaluate schedules calibrated to different training lengths or assess robustness when evaluation lengths are much shorter or longer than the schedule horizon.
- Beyond the training horizon, all memory blocks are active, so Proteus does not continue increasing effective capacity; its behavior at substantially longer contexts is therefore not a genuine test of indefinite incremental activation.
- The paper does not compare Proteus fairly against memory systems whose state size grows with context, such as expandable-memory or compressed-cache methods, despite identifying these as related alternatives.
- The claimed “no additional cost” is not fully substantiated for all supported architectures; masking, block management, optimizer-state handling, and implementation overhead may affect throughput, memory bandwidth, or parallel training efficiency.
- The interaction between gating and optimizer state is insufficiently examined, particularly for AdamW momentum, adaptive second moments, weight decay, and parameters that remain inactive for long periods before activation.
- It remains unclear how newly activated blocks are initialized, whether their initial values are zero or inherited, and whether initialization choices materially affect performance.
- The extension to Hope-Attention applies gating to model parameters during training, but the paper does not clarify the exact activation schedule, parameter grouping, update frequencies, or whether all MLP blocks follow the same schedule.
- The conceptual connection between recurrent memory activation and activation of trainable MLP parameters is asserted through the Nested Learning perspective but is not theoretically or experimentally validated as an equivalent mechanism.
- The experiments do not isolate whether Proteus improves generalization because it changes the optimization trajectory, acts as a form of regularization, or genuinely improves online memory allocation.
- No comparisons are provided with simpler regularization or scheduling baselines, such as learning-rate warm-up, weight decay changes, delayed parameter unfreezing, progressive layer growth, dropout, reduced initial memory size, or position-dependent step sizes.
- The reported improvements are generally modest on standard language modeling and commonsense benchmarks, and statistical significance, variance across random seeds, and confidence intervals are not reported.
- The evaluation uses only two model scales and a single FineWeb training corpus, leaving the scaling behavior across substantially smaller, larger, multilingual, domain-specific, and instruction-tuned models unresolved.
- The paper does not test whether Proteus remains effective under different data orders; because the mechanism is explicitly position-dependent, shuffled, curriculum-based, or nonstationary data streams may produce different outcomes.
- The long-context evaluation is concentrated on retrieval-heavy benchmarks, while performance on tasks requiring global synthesis, sustained multi-step reasoning, generation quality, planning, code, and dialogue continuity remains uncertain.
- The paper does not analyze how Proteus handles information that appears early but must be retrieved late, compared with information that arrives late and must be used immediately.
- The effects of multiple relevant facts being distributed across different activation stages are not systematically studied, especially when solving a task requires integrating early and late context.
- The evaluation does not test adversarial or pathological cases in which crucial information occurs during the early bottleneck, appears repeatedly, conflicts across positions, or requires precise memorization rather than compression.
- The paper does not determine whether incremental activation improves robustness to distractors, duplicated information, distribution shifts, or changing task relevance over the sequence.
- The relationship between context length and total memory capacity is not explored; it remains unknown whether the proposed schedule should activate capacity according to absolute position, relative position, estimated information content, or expected number of associations.
- The deterministic schedule cannot adapt to token predictability, semantic importance, or surprise, and the paper leaves open whether learned or data-dependent activation would outperform the fixed schedule.
- There is no analysis of whether prefix activation creates positional asymmetry or causes the earliest blocks to become disproportionately important, potentially reproducing the very interference or overuse problem the method is intended to solve.
- The paper does not report per-position retrieval accuracy or memory utilization, so it is unclear whether later blocks are actually used effectively after being unlocked.
- The robustness of Proteus to different memory update rules, retention mechanisms, momentum settings, and nonlinear memory architectures is asserted broadly but demonstrated only for a limited set of model families.
- The paper does not investigate combinations with local attention, external retrieval, recurrent memory expansion, sparse memory routing, or learned token-level routing, despite identifying these as promising directions.
- Reproducibility is limited by missing implementation details, including exact block layouts, masking semantics for each architecture, optimizer-state treatment, training schedules for the Hope variant, random seeds, and computational-resource accounting.
- The provided paper text ends during the conclusion, so the final limitations, complete conclusions, and any additional experimental qualifications are unavailable for assessment.
Practical Applications
Immediate Applications
- Long-context language-model deployment (software/AI infrastructure): Integrate Proteus-style block gating into compatible recurrent or associative-memory architectures such as SWLA, Comba, Titans, or Hope-Attention. This can improve language modeling, commonsense reasoning, and retrieval at long context lengths without increasing parameter count or total memory.
- Actionable workflow: partition the memory state into blocks, apply a deterministic prefix mask that gradually unlocks blocks with token position, and use the same mask for both memory reads and writes.
- Potential products: lower-cost document assistants, code-completion systems, customer-support agents, and enterprise chatbots capable of processing long conversations or documents.
- Dependencies: the target architecture must expose a writable memory or parameter-update mechanism; performance must be validated on the target domain rather than assumed from the reported benchmarks.
- Long-document question answering and retrieval (enterprise search, legal, and research): Use Proteus-enabled sequence models for querying lengthy reports, contracts, scientific papers, technical manuals, and collections of related documents.
- The reported improvements on LongBench, SQuAD-style retrieval, multi-document reasoning, and needle-in-a-haystack tasks suggest improved retention of information appearing later in a long context.
- Potential workflow: stream a document through the model, maintain a fixed-size state, and answer questions without storing every token in a quadratic attention cache.
- Dependencies: retrieval accuracy remains imperfect, especially on difficult multi-key and multi-value tasks; high-stakes applications should retain source citations and use external verification.
- Long-context code assistance (software engineering): Apply the method to code models that must track large repositories, long files, build logs, or extended debugging sessions.
- Incremental activation may reduce interference between early project-level information and later function-level details while preserving linear or sub-quadratic processing costs.
- Potential tools: repository summarizers, issue-to-code assistants, code-review systems, and streaming static-analysis agents.
- Dependencies: the paper evaluates natural-language and reasoning benchmarks rather than repository-level software engineering tasks, so repository-scale effectiveness requires direct testing.
- Streaming and memory-constrained inference (edge computing and mobile systems): Deploy fixed-memory sequence models on devices where transformer key–value caches are too expensive, such as mobile phones, embedded processors, and small servers.
- Proteus preserves a fixed total memory state and does not add parameters or memory, making it suitable for streaming speech, text, sensor, or event data.
- Potential workflow: process inputs incrementally while maintaining only the gated associative state instead of a token-by-token cache.
- Dependencies: the implementation must preserve the claimed computational advantage; masking may introduce hardware inefficiencies if inactive blocks are not efficiently skipped.
- Streaming speech and transcription assistance (speech technology): Use Proteus-based recurrent models for long meetings, lectures, call-center recordings, and live captioning.
- The model’s improved retention over long contexts could support speaker- or topic-consistent transcription and downstream summarization.
- Dependencies: speech recognition introduces acoustic noise, timing constraints, and modality-specific representations not studied in the paper. Latency and word-error-rate evaluations are required.
- Long-session conversational agents (consumer applications): Use incremental memory activation to maintain useful summaries across extended conversations without retaining the entire dialogue in attention memory.
- The early bottleneck can encourage compact summaries of initial exchanges, while later unlocked blocks provide space for newer conversational facts.
- Dependencies: the fixed positional schedule is not explicitly content-aware. Important early facts may be compressed away, and privacy controls are required for persistent user memory.
- Academic research and model engineering (research tooling): Use Proteus as a low-cost ablation or plug-in baseline for studying memory allocation, online learning, associative memory, and long-context generalization.
- Researchers can vary the number of blocks , expansion schedule, block layout, and activation timing without changing the underlying memory objective or optimizer.
- Potential tools: open-source gating modules, benchmark harnesses, and diagnostic visualizations of memory-block usage.
- Dependencies: reported gains are generally modest on standard tasks and larger on long-context tasks; reproducibility requires matching the 8K training setup, model scale, data, and optimizer conditions.
- Training-time capacity control (machine-learning workflows): Apply gated parameter updates to MLP blocks or other online-updated parameters during training.
- This may reduce early overfitting or memorization by exposing only part of the model’s capacity to early training examples.
- Potential workflow: combine Proteus masks with AdamW or another optimizer while freezing inactive parameter gradients and optimizer states.
- Dependencies: the paper provides only a proof-of-concept extension to Hope-Attention. Effects on convergence speed, optimizer state, catastrophic forgetting, and downstream transfer need to be measured.
Long-Term Applications
- Adaptive, content-dependent memory allocation (general AI systems): Replace the fixed position-based schedule with a learned policy that unlocks capacity according to surprise, information density, predictability, or task relevance.
- A future model could allocate more memory to an unexpected medical finding, a new software dependency, or a changing financial event, while compressing repetitive material more aggressively.
- Potential products: adaptive document agents, event-driven monitoring systems, and personalized assistants with learned memory policies.
- Dependencies: learned routing must remain stable, interpretable, and resistant to adversarial or noisy inputs; training such policies may add computational and optimization complexity.
- Healthcare record and clinical-trial analysis (healthcare): Use Proteus-like models to process longitudinal electronic health records, medical histories, clinical notes, and trial documentation.
- Incremental memory could support efficient tracking of events over years while limiting interference between old and recent observations.
- Potential tools: patient-history summarizers, clinical-trial monitoring systems, and longitudinal decision-support interfaces.
- Dependencies: clinical validation, privacy protection, auditability, bias testing, and regulatory approval are essential. The reported benchmarks do not establish clinical reliability and cannot justify autonomous diagnosis or treatment.
- Financial surveillance and risk analysis (finance): Apply long-context memory models to transaction streams, earnings reports, regulatory filings, and market-event histories.
- Fixed-memory streaming inference could reduce infrastructure costs for continuous anomaly detection and risk summarization.
- Potential workflows: alert generation, portfolio-event summarization, fraud investigation, and compliance review.
- Dependencies: financial data are nonstationary and adversarial; false positives, concept drift, latency, and explainability must be evaluated before deployment in regulated settings.
- Robotics and autonomous systems (robotics): Use incrementally activated recurrent memory for long-horizon navigation, manipulation, and human–robot interaction.
- The model could compress early observations of an environment and preserve later task-relevant events without maintaining a complete sensory history.
- Potential tools: robot task memory, warehouse-navigation controllers, and household-robot dialogue systems.
- Dependencies: real-time guarantees, multimodal sensor integration, robustness to distribution shift, and safety-critical validation are unresolved. The paper evaluates text sequence models, not embodied agents.
- Industrial monitoring and predictive maintenance (manufacturing and energy): Process long streams of sensor readings, maintenance logs, and operating conditions using fixed-memory sequence models.
- Proteus could help preserve recent anomalies while summarizing older operating history, reducing interference in long-running monitoring processes.
- Potential products: turbine or machine-health monitors, grid-event analyzers, and industrial alerting systems.
- Dependencies: sensor irregularity, missing data, changing equipment regimes, and the need for calibrated alerts require domain-specific modeling and evaluation.
- Educational tutoring and learning analytics (education): Build tutors that track long student interactions, misconceptions, assignments, and progress over a course or school year.
- Incremental memory may enable efficient retention of recent instructional context while compressing earlier interactions into a compact state.
- Potential tools: personalized feedback systems, curriculum-planning assistants, and teacher dashboards.
- Dependencies: pedagogical effectiveness is not demonstrated by commonsense benchmarks. Systems must address student privacy, age-appropriate safeguards, fairness, and teacher oversight.
- Hybrid memory architectures for extreme context lengths (AI infrastructure): Combine Proteus with external retrieval, sliding-window attention, or genuinely growing memory systems.
- A hybrid workflow could use Proteus for compact recurrent state, external storage for exact source retrieval, and full attention only for a small locally relevant window.
- Potential benefit: improved scalability beyond the 8K training window while retaining exact access to critical information.
- Dependencies: interfaces between compressed memory and external retrieval must prevent duplicated, stale, or contradictory information. The paper explicitly leaves combinations with growing-memory methods for future work.
- Dynamic capacity scheduling beyond sequence position (theoretical and applied ML): Generalize the principle from memory blocks to layers, experts, optimizer states, or model parameters.
- Models could progressively activate capacity across training stages, tasks, users, or environmental regimes rather than using a single static architecture.
- Potential tools: continual-learning systems, task-adaptive neural networks, and parameter-efficient personalization methods.
- Dependencies: the relationship between activation schedules and generalization is not yet theoretically characterized. It is necessary to determine when early compression improves robustness and when it causes irreversible information loss.
- Policy and public-sector information systems: Deploy efficient long-context models for legislation analysis, public-record search, emergency-response logs, and administrative case management.
- Fixed-memory processing could reduce the cost of handling large document streams and support more responsive public-information services.
- Dependencies: government use requires transparency, records retention, reproducibility, accessibility, and human review. Compression-based memory must not obscure legally relevant passages or prevent auditability.
Glossary
- Adaptive computation: Dynamically allocating different amounts of computation to different inputs or processing steps. “A parallel line of work reduces cost by allocating computation non-uniformly rather than spending full capacity on every input.”
- Associative memory: A memory mechanism that learns mappings between keys and values so that values can be retrieved from related queries. “an associative memory is an operator , parameterized by a set of memory parameters, that maps the keys to values in .”
- Backpropagation: The procedure for computing gradients through a neural network so its parameters can be updated. “each layer, updated by backpropagation, learns to map its input to the local error signal it receives.”
- Bottleneck: A deliberately restricted information or parameter capacity that forces compression. “an early capacity bottleneck that encourages compression of the initial context”
- Capacity-scheduled associative memory: An associative memory whose active parameters vary according to a schedule over the input sequence. “A capacity-scheduled associative memory updates online as”
- Conditional computation: A neural-network strategy in which only selected components are executed for a particular input. “This idea has a long history, from conditional computation”
- Cosine annealing: A learning-rate schedule that gradually decreases the learning rate according to a cosine-shaped function. “a cosine annealing schedule”
- Delta rule: An associative-memory update that removes an existing association before writing a new value. “yields a delta-rule update that first erases the current value along before writing ”
- Degrees of freedom: Independent parameters or representational dimensions available for storing or modeling information. “they occupy too many degrees of freedom and ``pollute'' the memory state”
- Dense associative memory: A high-capacity associative-memory model that uses distributed representations and nonlinear interactions to store patterns. “modern continuous variants have addressed these bottlenecks through dense associative memories and exponential kernels”
- Early exiting: Terminating computation before all network layers have been processed when the input is sufficiently easy. “to early-exiting methods that halt processing for easy inputs”
- Effective capacity: The number of memory parameters that are currently available for reading and updating. “We refer to the effective capacity of the memory at step as the number of memory parameters that are active”
- Empirical risk minimization: Training a model by minimizing its average loss over a finite training dataset. “high-capacity models trained by empirical risk minimization tend to memorize atypical examples”
- Exponential kernel: A similarity function that applies an exponential transformation to interactions between representations. “modern continuous variants have addressed these bottlenecks through dense associative memories and exponential kernels”
- Fast weight programmer: An architecture in which a slower network generates rapidly changing weights for a faster network. “The related paradigm of treating linear layers as dynamic, writable memory was formalized in fast weight programmers”
- Forget gate: A mechanism that controls how much previously stored state is retained or discarded. “Titans augments the update with momentum and an adaptive forget gate”
- Gradient descent: An optimization algorithm that updates parameters in the direction opposite to the gradient of a loss. “A common instantiation optimizes the internal objective by gradient descent”
- Hebbian learning: A learning rule that strengthens associations between simultaneously active representations. “Two learning rules dominate this setting, Hebbian learning and the delta rule”
- Hidden state: The fixed-size internal representation maintained by a recurrent neural network across time steps. “modern RNNs employ a fixed-size memory (a.k.a. a hidden state) to compress the context”
- Length extrapolation: The ability of a model to generalize to sequence lengths longer than those used during training. “their ability to generalize to sequence lengths beyond those seen in training”
- Linear attention: An attention formulation whose computation and memory requirements scale linearly rather than quadratically with sequence length. “Taking a dot-product objective and optimizing by gradient descent with a decay term recovers linear attention”
- Long-context understanding: A model’s ability to retrieve and reason over information distributed across very long input sequences. “We now evaluate Proteus on long-context understanding”
- Mask: A binary tensor that selects which parameters or representations participate in an operation. “for Proteus, this mask enables exactly the parameters belonging to the currently active blocks”
- Meta-learning: Learning procedures or initializations that enable a model to adapt efficiently to new data or tasks. “A substantial body of work has sought to close this gap through (meta-learning) memory initialization”
- Momentum: An optimization technique that accumulates information from previous gradients to influence future parameter updates. “where carries a running memory of past surprise (momentum)”
- Needle-in-a-haystack retrieval: A long-context evaluation in which a small target item must be found among many irrelevant tokens. “We evaluate long-context retrieval on Needle-in-a-Haystack (NIAH)”
- Nested Learning: A framework that interprets multiple levels of learning updates, including parameter updates, as forms of associative memory. “a recent perspective---Nested Learning---extends the same lens to a model's parameters”
- Non-parametric: Describing a method whose representational capacity is not fixed by a finite parameterized model and can grow with stored data. “softmax attention can be cast as the non-parametric solution to an regression objective”
- Online optimization: Updating a model incrementally as each new data point or token becomes available. “The memory in \cref{def:associative-memory} is learned online, one token at a time”
- Over-parameterized: Having substantially more model parameters than are apparently necessary to fit the training data. “an over-parameterized MLP early in training has ample capacity to fit its first samples”
- Perplexity: An exponential measure of a LLM’s average negative log-likelihood; lower values indicate better predictive performance. “We report perplexity on Wikitext and LAMBADA”
- Positional activation schedule: A rule that determines which parameters are active based on the current input position. “incremental activation restricts both the write and the read to the active subset”
- Retrieval: The process of producing stored information in response to a query or related representation. “While this makes attention well suited to retrieval”
- Sequence extrapolation: The ability to operate effectively on sequences longer than the model’s training sequences. “their ability to generalize to sequence lengths beyond those seen in training”
- Sliding-window attention: An attention mechanism that restricts each token’s attention to a local region of the sequence. “restricting that objective to a local window recovers sliding-window attention”
- Softmax attention: An attention mechanism that converts query–key similarities into normalized weights using the softmax function. “Softmax attention, the backbone of Transformers and the component mainly responsible for sequence mixing”
- State saturation: A condition in which a fixed-size memory has little unused capacity for incorporating new information. “later inputs interfere with an already-saturated state”
- Structural capacity control: Regulating a model’s effective complexity to influence generalization. “Classical capacity control restricts a model's degrees of freedom globally”
- Surprise signal: A gradient-based indication of how different a new association is from what the memory already represents. “The gradient acts as a surprise signal”
- Weight decay: A regularization method that penalizes large parameter values, commonly by shrinking weights during optimization. “weight decay of $0.1$”
- Zero-shot evaluation: Evaluating a model on a task without task-specific training examples or fine-tuning. “Downstream, we evaluate zero-shot on Wikitext”



