Explore or hide

In the absence of data I will just make up a blank sheet with half on one side and half on the other.

Since the process of evolution is so slow it is more likely that you would see worlds without any life and a vast number in the process of life. It would give a great advantage to the explorer, they would really be able to see the worlds develop in slow motion from their perspective. I think that eventually they would decide that waiting was wasting and plant something to form the way they chose. The exploration is critical to survival I would think. The more space that you could cover before there was a meeting. If there was a meeting in space, there would be a great chance that they were present long before us. If we are just learning how to travel and encounter someone who can travel as we do then they are more likely to be more advanced. Given this principle of exploration as an advantage over waiting for a kind stranger to give us advanced technology and power over them because we have shown ourselves to be a kind loving race. Waiting and hiding is not an option. ( Obviously the human race in general is violent, genocidal, xenophobic and weak. ) If I were an advanced society, I am not sure that I would give a second thought to simply cleaning this planet and establishing a base. If I had to judge the chances of this planet producing an effective presence in space in the next 4 million years, I would vote no on that because they would spend most of their time killing each other and that tends to make for awkward silences at the water cooler.