Raising a Small Language Model: From Imitation to Curiosity-Driven Learning in Dialogue Games

Varad Srivastava


Abstract
Children do not learn language from text corpora, rather they learn it in interaction by imitating competent speakers, receiving feedback, practicing, being corrected, and playing. The LM Playschool Challenge asks whether language models can profit from analogous regimes. We take the smallest recommended base model, Qwen3.5-2B (clemscore 13.63 in our evaluation environment), and traverse a sequence of five interaction-derived learning regimes that mirror a developmental progression: imitation of competent others (supervised fine-tuning on success-filtered transcripts), learning from outcome contrasts (direct preference optimisation), self-imitation (fine-tuning on the model’s own successes), corrective feedback (contrastive pairs from the model’s own failures against its own and expert successes), and intrinsically motivated trial-and-error (online GRPO with a novelty bonus). The offline regimes carry the model to 67.6 clemscore on our validation evaluation (+54.0 over the base model). On the organisers’ held-out evaluation, our two submitted checkpoints achieve the largest out-of-domain gains of any submission in the challenge (+11.9 and +10.8 clemscore, against a maximum of +6.5 for any other entry), with in-domain gains of +33.2 and +37.3 and static-benchmark performance unchanged. Online GRPO regresses from its initialisation (-5.0) unless augmented with a random-network-distillation novelty bonus, which fully recovers the loss (+5.0 over the plain-GRPO control), evidence that the bonus primarily counteracts the forgetting that narrow online training induces on untrained games.
Anthology ID:
2026.lmplayschool-1.13
Volume:
The Proceedings of Improving Language Models through Learning from Dialogue Game Interaction
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Alessandro Suglia, Mario Giulianelli, David Schlangen, Raffaella Bernardi, Raquel Fernández, Sherzod Hakimov, Sabrina McCallum, Davide Mazzaccara, Dieu-Thu Le, Oliver Lemon, Alexander Koller
Venues:
LM Playschool | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
148–159
Language:
URL:
https://aclanthology.org/2026.lmplayschool-1.13/
DOI:
Bibkey:
Cite (ACL):
Varad Srivastava. 2026. Raising a Small Language Model: From Imitation to Curiosity-Driven Learning in Dialogue Games. In The Proceedings of Improving Language Models through Learning from Dialogue Game Interaction, pages 148–159, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Raising a Small Language Model: From Imitation to Curiosity-Driven Learning in Dialogue Games (Srivastava, LM Playschool 2026)
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PDF:
https://aclanthology.org/2026.lmplayschool-1.13.pdf