# Improved Language Modeling by Decoding the Past

arXiv: https://arxiv.org/abs/1808.05908 · HTML: https://mlsanity.com/paper/1808.05908/

## Key facts

- Cited by 2 papers in the map (data through 14 Oct 2026).
- First posted on arXiv 14 Aug 2018.

## Built on by (most cited first, 2 of 2)

- [Cached Transformers: Improving Transformers with Differentiable Memory Cache](https://mlsanity.com/paper/2312.12742/) (2023)
- [The Importance of the Current Input in Sequence Modeling](https://mlsanity.com/paper/2112.11776/) (2021)

## Abstract (arXiv)

Highly regularized LSTMs achieve impressive results on several benchmark datasets in language modeling. We propose a new regularization method based on decoding the last token in the context using the predicted distribution of the next token. This biases the model towards retaining more contextual information, in turn improving its ability to predict the next token. With negligible overhead in the number of parameters and training time, our Past Decode Regularization (PDR) method achieves a word level perplexity of 55.6 on the Penn Treebank and 63.5 on the WikiText-2 datasets using a single softmax. We also show gains by using PDR in combination with a mixture-of-softmaxes, achieving a word level perplexity of 53.8 and 60.5 on these datasets. In addition, our method achieves 1.169 bits-per-character on the Penn Treebank Character dataset for character level language modeling. These results constitute a new state-of-the-art in their respective settings.