Reading book outloud copyright? It could be if the reader is a computer

An executive director of the Author's guild, Paul Aiken, has spoken out about the use of text-to-speech software reading text from a book out loud. He claims that this is an infringement of copyright. If such a notion was somehow justifiable, how could they distinguish the reading of a book by computer software and the reading of a book by a human being? Would it be an infringement if a human being, who relied on an electronic or computer generated voice, read a book out loud?