krou writes: Writing in Acta Astronautica, Seti astronomer Seth Shostak argues that we should be looking for 'sentient machines' rather than biological life. In an interview with the BBC, he said, "If you look at the timescales for the development of technology, at some point you invent radio and then you go on the air and then we have a chance of finding you. But within a few hundred years of inventing radio — at least if we're any example — you invent thinking machines; we're probably going to do that in this century. So you've invented your successors and only for a few hundred years are you... a 'biological' intelligence." As a result, he says "we could spend at least a few percent of our time... looking in the directions that are maybe not the most attractive in terms of biological intelligence but maybe where sentient machines are hanging out."