In-Context Learning: A Case Study of Simple Function Classes

Gregory Valiant (Stanford University)
simons.berkele...
Large Language Models and Transformers
In-context learning refers to the ability of a model to learn new tasks from a sequence of input-output pairs given in a prompt. Crucially, this learning happens at inference time without any parameter updates to the model. I will discuss our empirical efforts that shed light on some basic aspects of in-context learning: To what extent can Transformers, or other models such as LSTMs be efficiently trained to in-context learn fundamental function classes, such as linear models, sparse linear models, and small decision trees? How can one evaluate in-context learning algorithms? And what are the qualitative differences between these architectures with respect to their ability to be trained to perform in-context learning? I will also discuss subsequent work of other researchers which illuminates connections between language modeling and learning: must a good language model be able to perform in-context learning? Do large language models know how to perform regression? And are such primitives useful for language-centric tasks? This talk will be mostly based on joint work with Shivam Garg, Dimitris Tsipras, and Percy Liang.

[@henrylouis5143]

49:11 I think this is the most striking part of this talk: LSTM doesn't show numerical unstablity, meaning it never learns to "find the inverse matrix" as OLS does. But Transformer does learn it... Attention is all you need!

[@franky07724]

My tests on ChatGPT, Bing Chat, and Bard cannot get "4 - 1= 5" due to different reasons. Does it mean that they cannot perform in-context learning or contexts cannot overwrite weights?

[@prescod]

What's the Abraham Lincoln joke?

[@mshonle]

Abraham Lincoln said “if you call a ‘tail’ a ‘leg,’ a dog still has four legs”… in context, even if you call slavery by a different name it’s still slavery.