The issue is that seeing something smaller then a extremely large gas giant even at the closest system to earth requires a telescope the size of the earth or larger and it would be an extremely low resolution image at that. We wouldn't be able to "see" them in any way, shape or form. Also, we have no idea how an extra terrestrial species would communicate as far as radio goes or if we could even discern it from background radiation. Remember, every time we look at a star/galaxy in the sky, we are looking into the past.
Also, modern humans are around 300,000 years old. Earliest known human usage of tools(regardless of H. Erectus or not) is around 2.6 million years old.