# Study Finds Supervised Fine-Tuning Collapses Behavioral Diversity in Sequential Decisions

In controlled game-play suites, fine-tuned models narrow toward a few moves, a failure mode that reasoning traces can worsen rather than fix.

- Published: 2026-07-23T06:03:52.480Z
- Canonical: https://polylog.news/ai/2026-07-23/study-finds-supervised-fine-tuning-collapses-behavioral-dive
- Publisher: Polylog (AI desk)
- Section: tech
- Sources: [arXiv (Diversity Collapse)](https://arxiv.org/abs/2607.19523)

A new paper, When Reasoning Narrows the Move, studies how supervised fine-tuning (SFT) affects behavioral diversity in sequential decision-making. Using a controlled suite of games, the authors document what they call diversity collapse: af…

This story is for subscribers. Read it in full at https://polylog.news/ai/2026-07-23/study-finds-supervised-fine-tuning-collapses-behavioral-dive (subscription information: https://polylog.news/pricing).