Neurons and Attention Heads that Look for Sentence Structure in GPT2

GPT2 has great capabilities with respect to punctuation, grammar and sentence structure. We set out to specifically investigate how GPT2 accomplishes accurate capitalization of words after full stops, question marks and exclamation points. This was accomplished by analyzing both neurons and attention heads for a wide variety of inputs and a couple of models. We were able to narrow down to 2 attention heads of interest, including one that specifically focuses on punctuation marks that would have to be followed by capitalized letters.