  This work aims to build a text embedder that can capture characteristics of
texts specified by user instructions. Despite its tremendous potential to
deploy user-oriented embeddings, none of previous approaches provides a
concrete solution for it. This paper offers a new viewpoint, which treats the
instruction as a question about the input text and encodes the expected answers
to obtain the representation accordingly. Intuitively, texts with the same
(implicit) semantics would share similar answers following the instruction,
thus leading to more similar embeddings. Specifically, we propose InBedder that
instantiates this embed-via-answering idea by only fine-tuning language models
on abstractive question answering tasks. InBedder demonstrates significantly
improved instruction-following capabilities according to our proposed
instruction awareness tests and instruction robustness tests, when applied to
both large language models (LLMs) (e.g., llama-2-7b) and smaller encoder-based
LMs (e.g., roberta-large). Additionally, our qualitative analysis of clustering
outcomes, achieved by applying different instructions to the same corpus,
demonstrates a high degree of interpretability.
