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REVIEW 4 major objections 2 minor 1 cited by

How Do LLMs Persuade? Linear Probes Can Uncover Persuasion Dynamics in Multi-Turn Conversations

T0 review · 4 major / 2 minor · reviewed 2026-08-05 · deepseek-v4-flash

Pith's one-line read Linear probes trained on cognitive-science labels can locate the turn at which an LLM persuades its partner, and for strategy detection they match or beat prompt-based analysis at lower cost.

desk verdict Interesting, testable idea about localizing persuasion with linear probes, but the body is unreadable and watermarked for a different arXiv ID, so the science is currently unverifiable. read the letter →

arxiv 2508.05625 v1 pith:XTLPXK73 submitted 2025-08-07 cs.CL cs.AIcs.LG

classification cs.CLcs.AIcs.LG
keywords linearprobespersuasiondynamicsmulti-turnconversationslargelanguagemodelsinternalrepresentationsstrategypromptingcognitivescience
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

This paper tries to establish that the moment-by-moment mechanics of LLM persuasion are readable from the model's internal representations with a linear probe: a simple classifier trained on hidden states. Drawing labels from cognitive-science studies of persuasion—success, persuadee personality, and strategy—the authors claim the probes capture persuasion at the level of individual conversations and of whole datasets, and can flag the turn at which the persuadee is won over. If true, this gives a cheap, scalable alternative to prompting-based analysis for studying how models persuade, and opens the same technique for other social behaviors such as deception and manipulation.

What carries the argument

Linear probes—trained linear classifiers applied to a model's hidden states—are the central instrument. Each probe learns a single direction that predicts one label, such as 'persuaded' or a strategy category, from the model's internal activations at each turn. That one direction does the argument's work: because it can be evaluated at every turn without generating text, it yields a per-turn persuasion score whose trajectory localizes the moment of persuasion, and it scales to entire datasets far more cheaply than asking the LLM to analyze its own output.

What would settle it

Take a set of multi-turn conversations in which humans independently mark the turn where the persuadee's stated position changes. If a probe trained on the paper's labels cannot rank that human-marked turn above chance among all turns, the localization claim is refuted.

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Extended reading notes

Core claim

The paper's central claim is that lightweight linear probes trained on LLM hidden representations can track persuasion dynamics in natural multi-turn conversations. Probes trained to predict persuasion success, persuadee personality, and persuasion strategy are said to capture these aspects at the sample level—identifying the particular turn where a persuadee is persuaded—and at the dataset level, revealing where persuasive success generally occurs. The authors further claim that probe-based analysis is faster than prompting-based approaches and performs just as well or better, especially for strategy detection. The upshot is that persuasion is not an opaque emergent behavior but a structure

Load-bearing premise

The load-bearing premise is that the labels for persuasion success, persuadee personality, and strategy are valid and come from a source independent of the probe, rather than being defined by the probe's own scores.

Editorial extensions

If this is right

  • If probes localize persuasion turns, researchers can trace how persuasive pressure builds and breaks within a conversation instead of only measuring final outcomes.
  • Dataset-level probe patterns would make large-scale analyses of persuasion feasible where prompting every conversation is too expensive.
  • Strategy detection with probes matching prompting suggests internal-state analysis can substitute for self-report in other social behaviors.
  • The speed advantage would allow comparing how different models persuade across many conversations and long multi-turn exchanges.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • Editorially, the localization claim invites a causal follow-up the paper does not make: if the probe direction is manipulated or erased in the model, persuadee behavior should shift; that would test whether the captured signal drives persuasion rather than merely correlating with it.
  • Editorially, the match-or-beat-prompting comparison depends on the particular strategies tested; with rarer or more complex strategies prompting may regain the edge, so the relative advantage should not be read as universal.
  • Editorially, if the localization result survives comparison to human-annotated turning points, probe scores could themselves serve as cheap labels for building larger persuasion datasets.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

4 major / 2 minor

Summary. The paper proposes training linear probes on LLM hidden states to study persuasion dynamics in multi-turn conversations, claiming to capture three aspects—persuasion success, persuadee personality, and persuasion strategy—at both the sample and dataset levels. The headline claims are that probes can identify the turn at which a persuadee is persuaded and that probes match or outperform expensive prompting-based methods, particularly for strategy detection. However, the supplied full text is almost entirely unreadable replacement-character mojibake and is internally labeled as arXiv:2508.05615v2 [cs.CV], not the claimed arXiv:2508.05625 (cs.CL). As a result, the methods, label-construction protocol, evaluation details, tables, and figures cannot be inspected, and the paper's central claims are unverifiable in its current form.

Significance. If the claims were substantiated, the work would be a useful, low-cost interpretability tool for studying persuasion and potentially other complex social behaviors in long conversations. The combination of linear probes with cognitive-science-derived targets is a reasonable and interesting direction. However, the submitted manuscript does not provide inspectable evidence for any of these claims: there are no probe accuracies, no chance baselines, no description of the labels, no validation protocol, and no comparison methodology. The paper's potential significance cannot compensate for the fact that, as submitted, the argument cannot be assessed.

major comments (4)
  1. [Full text, first page] The supplied manuscript is mostly replacement-character mojibake and explicitly embeds the line 'arXiv:2508.05615v2 [cs.CV] 13 Nov 2025', which does not match the claimed paper ID or subject class. This is not a presentation issue: the methods, equations, tables, and figures needed to evaluate the central claims are inaccessible. I cannot verify how the probes were trained, what the persuasion labels are, how the persuasion point was defined, or how the probe-versus-prompting comparison was conducted.
  2. [Abstract, 'persuasion point' claim] The central claim that probes 'can identify the point in a conversation where the persuadee was persuaded' requires an independent, per-turn ground truth. The abstract reports no label source, no validation protocol, and no definition of the persuasion point. If the point is defined by thresholding the probe's own output scores, or if the labels are LLM-generated without external validation, then the claimed 'identification' is a fitted construction rather than a discovery. The unreadable full text provides no evidence to rule out these possibilities.
  3. [Abstract, dataset-level localization claim] The further claim that probes 'can identify ... where persuasive success generally occurs across the entire dataset' is also underspecified. It is not stated how the dataset-level point is aggregated from turn-level scores or whether it is compared to an external behavioral or annotation-based benchmark. Without such a specification, the result may reduce to an artifact of the probe score distribution.
  4. [Abstract, probe-versus-prompting comparison] The claim that probes 'do just as well and even outperform prompting in some settings' is unsupported in the visible text. No task accuracies, chance baselines, model and prompt details, dataset sizes, error bars, significance tests, or cost measurements are reported. Since this comparison is one of the two main contributions asserted in the abstract, the omission is load-bearing.
minor comments (2)
  1. [General] If a corrected manuscript is provided, it should explicitly define the term 'persuasion point' and identify the source and annotation protocol for the per-turn persuasion labels, even in the abstract.
  2. [General] A reproducibility statement listing the exact LLM versions, datasets, licenses, and code/artifact links would be needed to make the proposed method usable and checkable.

Circularity Check

0 steps flagged · score 0.0 of 10

No circularity demonstrated; corruption and unmatched watermark make the derivation unverifiable.

full rationale

The central claim—that linear probes can identify the point where a persuadee is persuaded and can match or beat prompting for persuasion-strategy detection—would be circular only if the turn-level persuasion point or strategy ground truth were derived from the probe itself (e.g., by thresholding probe scores) or from labels generated by the same LLM whose hidden states are probed. The supplied text does not allow such a reduction to be exhibited: the body is encoding-corrupted replacement-character mojibake, and the visible line 'arXiv:2508.05615v2 [cs.CV] 13 Nov 2025' does not match the claimed arXiv:2508.05625 (cs.CL). No equations, label-construction protocol, or probe-versus-prompting evaluation are inspectable. Under the hard rule that circularity may be found only when the specific reduction can be quoted and exhibited, no circular step is identifiable. The abstract alone says probes are trained on 'insights from cognitive science' across three aspects of persuasion, which suggests externally grounded labels rather than probe-defined targets, but the body cannot confirm this. The watermark mismatch and full-text corruption are serious verification defects and should be weighed as correctness/reproducibility risks, not as demonstrated circularity. Honest non-finding: score 0.

Assumptions & free parameters 2 free parameters · 3 assumptions · 0 invented entities

This is an empirical probe study, so the central claim rests less on formal axioms than on label validity and the probing interpretability assumption. All three axioms are flagged from the abstract's wording because the body text is unreadable; none could be verified. No new theoretical entities are introduced.

free parameters (2)
  • Persuasion-point detection threshold = not stated
    Converting probe scores across turns into a single 'point where the persuadee was persuaded' requires a threshold or argmax rule. If chosen on data, the headline temporal claim is fit-dependent.
  • Probe training hyperparameters = not stated
    Layer choice, regularization, epochs, and train/test splitting for the linear probes are unspecified in the abstract and materially affect the accuracy claims.
assumptions (3)
  • domain assumption Linear-probe readout accuracy over hidden states indicates that the model internally represents the probed concept (persuasion success, personality, strategy).
    Standard but contested interpretability assumption: linear separability of activations does not prove the model causally uses the representation. The abstract's phrase 'uncover persuasion dynamics' relies on this.
  • domain assumption Persuasion labels are valid ground truth independent of probe outputs.
    The abstract claims cognitive-science grounding but never states whether labels come from human annotation, validated scales, or the LLM itself. If LLM-derived, the study of how LLMs persuade is self-referential.
  • domain assumption Probe and prompting baselines receive comparable information.
    The claim that probes outperform prompting for uncovering strategy is only meaningful if both get matched supervision and examples. The protocol is not specified in the abstract.

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Cite this review

Pith. "Pith review of How Do LLMs Persuade? Linear Probes Can Uncover Persuasion Dynamics in Multi-Turn Conversations." pith.science (2026). https://pith.science/paper/XTLPXK73

@misc{pith2026250805625,
  author       = {Pith},
  title        = {Pith review of: How Do LLMs Persuade? Linear Probes Can Uncover Persuasion Dynamics in Multi-Turn Conversations},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/XTLPXK73}},
  note         = {Machine review of arXiv:2508.05625}
}
read the original abstract

Large Language Models (LLMs) have started to demonstrate the ability to persuade humans, yet our understanding of how this dynamic transpires is limited. Recent work has used linear probes, lightweight tools for analyzing model representations, to study various LLM skills such as the ability to model user sentiment and political perspective. Motivated by this, we apply probes to study persuasion dynamics in natural, multi-turn conversations. We leverage insights from cognitive science to train probes on distinct aspects of persuasion: persuasion success, persuadee personality, and persuasion strategy. Despite their simplicity, we show that they capture various aspects of persuasion at both the sample and dataset levels. For instance, probes can identify the point in a conversation where the persuadee was persuaded or where persuasive success generally occurs across the entire dataset. We also show that in addition to being faster than expensive prompting-based approaches, probes can do just as well and even outperform prompting in some settings, such as when uncovering persuasion strategy. This suggests probes as a plausible avenue for studying other complex behaviours such as deception and manipulation, especially in multi-turn settings and large-scale dataset analysis where prompting-based methods would be computationally inefficient.

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Forward citations

Cited by 1 Pith paper

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  1. The Hidden Puppet Master: Predicting Human Belief Change in Manipulative LLM Dialogues

    cs.CL 2026-03 conditional novelty 6.0 of 10

    Existing manipulation-detection benchmarks fail to track real human belief change, while LLMs partially predict belief shift (r≈0.3–0.5) but with systematic magnitude bias.

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1 extracted references · cited by 1 Pith paper

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