Why is GPT generally better than BERT for generating long answers?
PICTURE THIS: A SENTENCE BECOMES TOKENS
The model does not read letters like humans. It reads these pieces, then predicts the next one.
Simple meaning
GPT is trained as a language model that writes the next token, so generation is its native task.
WHY — GPT vs BERT instead of guessing?
Why interviewers care about GPT vs BERT:
on GPT vs BERT.
the situation, the default choice, and one exception - that reads as experience.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens with tokens?
Before the model can read a sentence, it goes through these steps:
- 1GPT is trained as
a language model that writes the next token, so generation is its native task.
- 2BERT is trained to
reconstruct masked tokens, not to continue a story.
- 3You can force BERT-like
models to generate, but decoder-only LLMs are the production default for chat.
- 4Context mix
Attention looks at nearby tokens together.
- 5Next token
The model scores what should come next.
- 6Decode
IDs turn back into readable text.
EXAMPLE — See it in action
Let's see how a real sentence is tokenized (tokens may vary by model):
Note: Actual tokens and IDs depend on the tokenizer (e.g., GPT, Llama, etc.).
Key takeaway
GPT is trained as a language model that writes the next token, so generation is its native task. BERT is trained to reconstruct masked tokens, not to continue a story.