Effective Pretraining Objectives for Transformer-based Autoencoders

In this paper, we study trade-offs between efficiency, cost and accuracy when pretraining Transformer encoders with different pre-training objectives. For this purpose, we analyze features of common objectives and combine them to create new effective pretraining approaches. Specifically, we designed light token generators based on a straightforward statistical approach, which can replace ELECTRA computationally heavy generators, thus highly reducing cost. Our experiments also show that (i) there are more efficient alternatives to BERT's MLM, and (ii) it is possible to efficiently pre-train Transformer-based models using lighter generators without a significant drop in performance.