lost in the middle
/ˌlɒst ɪn ðə ˈmɪdl/
the tendency to miss information buried midway through a long context
lost in the middle in a sentence
“The clause was in the brief verbatim, but lost in the middle, the model never cited it.”
Origin of lost in the middle
named in position-bias studies of long contexts (Liu et al., 2023)
Related Words
refusal
a model declining a request, sometimes wrongly, when it misreads intent as harmful
data contamination
test material leaking into training data, inflating benchmark scores
prompt leakage
a model revealing its hidden system prompt when coaxed
hallucination
generating plausible-sounding but factually incorrect or fabricated information
sycophancy
over-agreeing with users and telling them what they want to hear rather than the truth
confabulation
filling gaps in knowledge with plausible but invented details