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Understanding How Encoder-Decoder Architectures Attend
Kyle Aitken · Vinay Ramasesh · Yuan Cao · Niru Maheswaranathan

Tue Dec 07 04:30 PM -- 06:00 PM (PST) @

Encoder-decoder networks with attention have proven to be a powerful way to solve many sequence-to-sequence tasks. In these networks, attention aligns encoder and decoder states and is often used for visualizing network behavior. However, the mechanisms used by networks to generate appropriate attention matrices are still mysterious. Moreover, how these mechanisms vary depending on the particular architecture used for the encoder and decoder (recurrent, feed-forward, etc.) are also not well understood. In this work, we investigate how encoder-decoder networks solve different sequence-to-sequence tasks. We introduce a way of decomposing hidden states over a sequence into temporal (independent of input) and input-driven (independent of sequence position) components. This reveals how attention matrices are formed: depending on the task requirements, networks rely more heavily on either the temporal or input-driven components. These findings hold across both recurrent and feed-forward architectures despite their differences in forming the temporal components. Overall, our results provide new insight into the inner workings of attention-based encoder-decoder networks.

Author Information

Kyle Aitken (Allen Institute)
Vinay Ramasesh (Google)
Yuan Cao (Google Brain)
Niru Maheswaranathan (Meta Platforms, Inc.)

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