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How far is next-token prediction from answering a person?

Separate three questions: how an input becomes a representation, how training changes a network and how a capable text predictor becomes an assistant. An explanation at one level does not settle the others.

Questions in this reading · 7
  1. What is geometric about a word embedding?
  2. What does attention add to layered activations?
  3. How does a network change after a wrong answer?
  4. What does dropout do inside a GPT training loop?
  5. How can many subnetworks share one set of weights?
  6. From predicting a token to using a language model
  7. When does a text predictor become an assistant?

What is geometric about a word embedding?

Coordinates describe a vector relative to a basis. Embeddings use learned vectors whose directions can capture relationships among words.

Compare original passages and timestamps · 2
the ability to translate back and forth between them
Vectors | Chapter 1, Essence of linear algebra · ▶ 8:45–8:49
directions in the space have a kind of semantic meaning
Transformers, the tech behind LLMs | Deep Learning Chapter 5 · ▶ 14:28–14:34

What does attention add to layered activations?

A feedforward network propagates activations through its layers. Causal attention lets each position combine information from earlier tokens.

Compare original passages and timestamps · 2
the heart of the network as an information processing mechanism
But what is a neural network? | Deep learning chapter 1 · ▶ 4:39–4:43
you can do weighted aggregations of your past Elements
Let's build GPT: from scratch, in code, spelled out. · ▶ 57:59–58:14

How does a network change after a wrong answer?

Forward propagation computes a prediction. In micrograd, a loss and its gradients connect that prediction to the next parameter update.

Compare original passages and timestamps · 2
the entire network is just a function
But what is a neural network? | Deep learning chapter 1 · ▶ 15:39–15:43
efficiently evaluate the gradient of some kind of a loss function
The spelled-out intro to neural networks and backpropagation: building micrograd · ▶ 0:55–1:07

What does dropout do inside a GPT training loop?

The subnetworks interpretation explains why units are omitted during training. The implementation shows where the random masking happens in an actual model.

Compare original passages and timestamps · 2
all of these architectures are sharing the same weights, which is regularizing them a lot.
Brains, Sex, and Machine Learning · ▶ 17:13–17:20
training an ensemble of sub networks and then at test time everything is fully enabled
Let's build GPT: from scratch, in code, spelled out. · ▶ 99:07–99:16

How can many subnetworks share one set of weights?

Dropping units during training can be viewed as training different subnetworks with shared parameters. The test-time prediction is not necessarily their exact arithmetic mean.

Compare original passages and timestamps · 2
all of these architectures are sharing the same weights, which is regularizing them a lot.
Brains, Sex, and Machine Learning · ▶ 17:13–17:20
training an ensemble of sub networks and then at test time everything is fully enabled
Let's build GPT: from scratch, in code, spelled out. · ▶ 99:07–99:16

From predicting a token to using a language model

Building a predictor makes its training target concrete. Using a trained model shows how context and instructions put that predictor to work.

Compare original passages and timestamps · 2
give it the start of a sequence and it completes the sequence
Let's build GPT: from scratch, in code, spelled out. · ▶ 1:50–2:05
knows how to predict the next word
A Hackers' Guide to Language Models · ▶ 1:33–1:43

When does a text predictor become an assistant?

Next-token prediction teaches continuation. Compare how later training shapes responses to a user; the distinction does not prescribe a single post-training algorithm.

Compare original passages and timestamps · 2
it takes the model from being a document completer to a question answerer
Let's build GPT: from scratch, in code, spelled out. · ▶ 114:09–114:19
we swap out the data set now and we train on these Q&A documents
[1hr Talk] Intro to Large Language Models · ▶ 16:26–16:38

Try it on your own example

When an answer improves, does the evidence identify the representation, training objective or post-training as the cause?