Just look at this ivory number, which dates to the middle of the 7th century BCE (meaning about 650 or so.) Recall the sphinx from the story of Oedipus the King. In that story, she is a horrifying and debilitating monster without redeeming qualities, devouring all passersby who cannot answer her stupid riddle, and so perched over a pile of rotting human bones. Yech.
But, look. This is the Sphinx? Well, she does combine the requisite features of human face, lion body, and wings of an eagle, so she fits the genus. (The Sphinx is originally Egyptian.) But that face is no longer dangerous, no longer terrifying, and not especially hungry. She's thinking. Maybe she is thinking it all over. Robin Osborne calls her an "entirely Greek Sphinx, referring to her "pensive human visage." "We have moved," he concludes, "from a world of fabulous beasts to one in which it is their wits that men and women pit against whatever the gods send" (51).
Something important is happening here. We are beginning to see artists engaged not only in reproducing or inventing characters and things, but expressing states of consciousness. You might at first think of her as inexpressive, but you can't look long at this piece without coming away with a sense that whatever she may be thinking about, she is at least rapt in thought. The exploration of consciousness will become a major theme of Greek art.