PaLM 2
By Google
PaLM 2 was Google's second-generation Pathways Language Model, announced in May 2023, that powered products including Bard, Google Workspace's Duet AI features, and the Med-PaLM 2 medical model before being succeeded by the Gemini family.
Definition
PaLM 2 was Google's second-generation Pathways Language Model, announced in May 2023, that powered products including Bard, Google Workspace's Duet AI features, and the Med-PaLM 2 medical model before being succeeded by the Gemini family.
Overview
PaLM 2 followed the original 540-billion-parameter PaLM model and was designed to improve multilingual, reasoning, and coding capability while being more compute-efficient to train and serve. Google did not disclose PaLM 2's exact parameter count, but it was reported to be smaller than the original PaLM despite outperforming it on many benchmarks, reflecting an emphasis on "compute-optimal" scaling — training smaller models on proportionally more data, in the spirit of DeepMind's Chinchilla findings. Google released PaLM 2 in four sizes — Gecko, Otter, Bison, and Unicorn, from smallest to largest — available through Google Cloud's Vertex AI platform for enterprise customers, while a version of PaLM 2 powered the consumer-facing Bard chatbot starting in May 2023. Specialized variants were built on top of PaLM 2, including Med-PaLM 2 for medical question answering and Sec-PaLM for cybersecurity use cases, and Codey, a code-generation variant. PaLM 2 represented an important transitional model for Google: it was trained with improved multilingual data (reportedly supporting over 100 languages) and demonstrated stronger reasoning and coding performance than its predecessor. However, it was relatively short-lived as Google's flagship offering — by December 2023, Google introduced Gemini as its next-generation, natively multimodal model family, and Gemini progressively replaced PaLM 2 across Bard (renamed Gemini in 2024), Vertex AI, and Workspace products through 2024. PaLM 2 is now primarily of historical interest, marking the last of Google's PaLM lineage before the Gemini era.
Key Features
- Released in four sizes: Gecko, Otter, Bison, and Unicorn
- Compute-efficient training emphasizing data scaling over raw parameter count
- Strong multilingual support across 100+ languages
- Improved reasoning and coding performance over the original PaLM
- Powered Google Bard from May 2023 until the Gemini transition
- Available to enterprises via Google Cloud Vertex AI
- Basis for specialized variants: Med-PaLM 2, Sec-PaLM, and Codey