Mental Imagery That Matters: Curing Latent Collapse in Multimodal Reasoning

Mi Luo1, Rohan Dugad1, Zihui Xue1, Alex Dimakis2,3, Kristen Grauman1

1UT Austin2UC Berkeley3Bespoke Labs

NeurIPS 2026


A robot reasons with text and visual latents. Drop, Cross and Shuffle perturbations hurt far less on the visual blocks than on the text blocks across four models.

TL;DR: Latent-reasoning MLLMs often ignore their own visual latents. We call this Mental Simulation Collapse. AnchorSim trains models to use them, and improves visual reasoning on 9 benchmarks.

Mental Simulation Collapse

Models can now think in continuous visual latents between text steps. But does the answer depend on them?

We perturb a model's own latents and re-score its answer. Corrupting the visual latents barely moves the answer, while the same perturbations on text are usually far more damaging.

Alignment is not useMatching helper-image embeddings shapes how latents look, not whether the decoder relies on them.
Text-only loss cannot tellA decoder can reach nearly the same likelihood while ignoring the latents.

AnchorSim

Two training signals make generated latents consequential. The extra branches are dropped at inference.

AnchorSim framework: a visual-blind student, a student, and an EMA teacher conditioned on the answer.
Contrastive latent anchoringPush predictions away from a visual-blind branch, so ignoring the latents is penalized.
Anchored reasoning distillationMatch an EMA teacher that also sees the answer, so the latents are used well.

Results

ModelBLINK JigsawBLINK AvgV*MMVPEMMAVisuLogic
GPT-4o*-60.066.070.7--
Claude-4-Sonnet*-39.615.2---
Vision-R1*27.351.080.172.624.315.2
PixelReasoner*52.7-80.6-23.523.4
LVR*52.752.581.772.0--
CoVT62.756.078.077.322.724.6
SkiLa45.353.084.375.321.524.1
Qwen2.5-VL-7B61.355.577.574.024.325.6
Qwen2.5-VL-7B (interleaved)64.7 (+3.4)58.0 (+2.5)79.1 (+1.6)75.7 (+1.7)25.5 (+1.2)25.8 (+0.2)
AnchorSim-7B (Ours)66.0 (+4.7)59.4 (+3.9)82.7 (+5.2)78.3 (+4.3)26.0 (+1.7)27.5 (+1.9)
ModelCV-Bench 2DCV-Bench 3DSAT-RVSPCoMTAvg
Vision-R1*8.037.6----
CoVT76.084.764.76.027.848.6
SkiLa76.774.456.74.332.347.5
Qwen2.5-VL-7B76.673.359.79.339.548.9
Qwen2.5-VL-7B (interleaved)76.7 (+0.1)77.3 (+4.0)65.3 (+5.6)74.8 (+65.5)56.3 (+16.8)59.7 (+10.8)
AnchorSim-7B (Ours)80.4 (+3.8)86.4 (+13.1)68.7 (+9.0)78.0 (+68.7)58.0 (+18.5)62.4 (+13.5)

Table 1. Comparison across 9 visual reasoning benchmarks. Best in bold underline, second-best in bold. Numbers in parentheses are gains over Qwen2.5-VL-7B. Avg uses BLINK Avg and the CV-Bench mean. *Results are reported from prior work.

AnchorSim-7B has the best average and ranks first on 7 of the 9 benchmarks and second on BLINK and V*.

Example

AnchorSim-7B and SkiLa-7B on a SAT-R spatial reasoning question.
Qualitative example on SAT-R. Blue squares denote visual latent tokens, which are not decoded into images.

BibTeX

@inproceedings{luo2026anchorsim,
  title={Mental Imagery That Matters: Curing Latent Collapse in Multimodal Reasoning},
  author={Luo, Mi and Dugad, Rohan and Xue, Zihui and Dimakis, Alex and Grauman, Kristen},
  booktitle={Advances in Neural Information Processing Systems},
  year={2026}
}