Recognition: unknown
Beyond Decodability: Reconstructing Language Model Representations with an Encoding Probe
Pith reviewed 2026-05-09 19:29 UTC · model grok-4.3
The pith
An encoding probe reconstructs language model representations from interpretable features, revealing independent contributions from syntax and lexicon while speaker effects vary by training.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
By reversing the direction of analysis, the encoding probe reconstructs model representations from interpretable feature sets. Evaluation on transformer models indicates that speaker-related effects vary strongly across different training objectives and datasets, while syntactic and lexical features contribute independently to reconstruction.
What carries the argument
The Encoding Probe, which takes interpretable features as input to reconstruct the model's internal representations and measures how well different feature groups explain the representation.
If this is right
- Speaker-related features influence representations differently based on training objectives and datasets.
- Syntactic and lexical features provide non-overlapping contributions to model representations.
- Contributions of various features can be compared directly without correlation bias.
- The probe works for both text and speech transformer models.
Where Pith is reading between the lines
- Researchers could use this to identify minimal feature sets needed for certain model capabilities.
- It might help explain performance differences between models trained on different data.
- The method could extend to analyzing other types of neural networks beyond language models.
Load-bearing premise
That the chosen feature sets are complete and free of unaccounted correlations, allowing differences in reconstruction to be attributed to the features themselves.
What would settle it
Observing no difference in reconstruction when using combined versus separate syntactic and lexical features, or consistent speaker effects across all models, would challenge the claims of independence and variation.
Figures
read the original abstract
Probing is widely used to study which features can be decoded from language model representations. However, the common decoding probe approach has two limitations that we aim to solve with our new encoding probe approach: contributions of different features to model representations cannot be directly compared, and feature correlations can affect probing results. We present an Encoding Probe that reverses this direction and reconstructs internal representations of models using interpretable features. We evaluate this method on text and speech transformer models, using feature sets spanning acoustics, phonetics, syntax, lexicon, and speaker identity. Our results suggest that speaker-related effects vary strongly across different training objectives and datasets, while syntactic and lexical features contribute independently to reconstruction. These results show that the Encoding Probe provides a complementary perspective on interpreting model representations beyond decodability.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper introduces an Encoding Probe that reverses the typical probing direction by reconstructing language model representations from sets of interpretable features (acoustics, phonetics, syntax, lexicon, speaker identity). It argues this addresses two limitations of decoding probes: inability to directly compare feature contributions and confounding by feature correlations. Evaluation on text and speech transformers yields the claims that speaker-related effects vary strongly across training objectives and datasets while syntactic and lexical features contribute independently to reconstruction.
Significance. If the reconstruction results can be shown to be robust to feature correlations and omissions, the Encoding Probe would supply a useful quantitative complement to decodability-based interpretability methods, allowing direct assessment of how much variance in model activations is explained by specific linguistic properties. The approach is particularly relevant for comparing representations across training regimes in both NLP and speech models.
major comments (2)
- [Abstract] The central claim that syntactic and lexical features 'contribute independently' (Abstract) rests on the assumption that the chosen feature sets are mutually non-redundant and exhaustive. The manuscript provides no indication that multicollinearity was diagnosed, features were orthogonalized, or residual variance was examined for systematic structure after fitting, which is required to attribute reconstruction-error differences cleanly to the named categories rather than to unmeasured correlations.
- [Abstract] The abstract reports evaluation on text and speech models with multiple feature sets yet supplies no quantitative reconstruction metrics, error bars, confidence intervals, or controls for feature correlations. Without these, the strength of the reported variation in speaker effects and the independence of syntactic/lexical contributions cannot be assessed.
minor comments (2)
- [Abstract] The abstract does not name the specific models, datasets, or training objectives used in the evaluation, which would help readers contextualize the claimed variation across objectives.
- Consider including a table or figure that reports per-feature-set reconstruction performance (e.g., R² or MSE) across models to make the independent-contribution claim visually verifiable.
Simulated Author's Rebuttal
We thank the referee for the constructive comments, which help clarify how to strengthen the presentation of the Encoding Probe's claims. We address each major comment below and will revise the manuscript accordingly.
read point-by-point responses
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Referee: [Abstract] The central claim that syntactic and lexical features 'contribute independently' (Abstract) rests on the assumption that the chosen feature sets are mutually non-redundant and exhaustive. The manuscript provides no indication that multicollinearity was diagnosed, features were orthogonalized, or residual variance was examined for systematic structure after fitting, which is required to attribute reconstruction-error differences cleanly to the named categories rather than to unmeasured correlations.
Authors: We agree that explicit checks for multicollinearity and residual structure are necessary to support clean attribution of independent contributions. In the revised manuscript we will add a dedicated diagnostics subsection that reports variance inflation factors across all feature sets, incremental reconstruction performance when features are added sequentially, and an analysis of residuals after the full model fit to identify any remaining systematic variance. These additions will directly address the concern while preserving the core argument that the encoding direction reduces certain confounding issues relative to decoding probes. revision: yes
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Referee: [Abstract] The abstract reports evaluation on text and speech models with multiple feature sets yet supplies no quantitative reconstruction metrics, error bars, confidence intervals, or controls for feature correlations. Without these, the strength of the reported variation in speaker effects and the independence of syntactic/lexical contributions cannot be assessed.
Authors: We accept that the current abstract lacks the quantitative anchors needed for readers to evaluate the reported effects. We will revise the abstract to include representative reconstruction metrics (e.g., mean R² values for syntactic-plus-lexical versus full feature sets) together with standard errors or confidence intervals, and we will note that correlation diagnostics and controls are now detailed in the main text. This change will make the strength of the speaker-effect variation and feature-independence claims directly assessable from the abstract. revision: yes
Circularity Check
No circularity: empirical reconstruction via standard regression on independent feature sets
full rationale
The paper defines an encoding probe as a regression that reconstructs model hidden states from a fixed set of external, human-interpretable features (acoustics, phonetics, syntax, lexicon, speaker). Reconstruction quality is measured by held-out error or correlation; differences across feature groups are reported directly from these fits. No equation equates a target quantity to a parameter fitted from the same quantity, no prediction is a renamed fit, and no load-bearing premise reduces to a self-citation chain. The central claims about independent contributions and speaker variation follow from comparing reconstruction metrics across disjoint feature subsets; these metrics are computed from the data and are not definitionally forced by the probe formulation itself. The approach is therefore self-contained against external benchmarks.
Axiom & Free-Parameter Ledger
Reference graph
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