attention not only to the left but also to the right to everything right so why do these other model whether for example the opening I transformer only look to the left that's because somehow you need a task to train on right and most of the time if you especially if you want unsupervised training you going to do something like language modeling and language modeling what you have is a sentence ABCD and you're asking what comes next here alright so by by the definition of the task you can only look to the left