Blank Language Models
Table 3: Accuracy and BLEU scores for the Yelp sentiment transfer task. Accuracy measures the percentage of sentences labeled as the target sentiment by the classifier. BLEU is evaluated against human reference generations. For reference, we also report accuracy and BLEU scores of the canvas (i.e. the original masked sentence).
['[EMPTY]', 'ACC (%)', 'BLEU']
The Delete-And-Retrieve method with the frequency-ratio based masking strategy achieves high sentiment accuracy, but can only do so at the expense of content fidelity. By constraining BLM to fill in blanks in between content words, we ensure that the predictions will yield high content preservation, improving both BLEU score and sentiment accuracy over the original masked sentence.