Yes and yes.
Try this sometime - when you encounter someone and begin speaking to them, look them in the eye. Really look at them. Do this especially to those with whom you don't normally behave this way. See, if it doesn't change the dynamics of the meeting.

We always see the bike-auto encounter as only one sided, even adversarial... us against them. But we share the same road. Nearly all drivers I ask admit that. These drivers are also as concerned with you as you are with them.

Basically, they want to know you aren't going to do anything stupid, either.

If you try talking to drivers about cyclists, you'll hear them comment on two things very often,
1. Cyclists are a bother, taking up the road AND
2. They fear the cyclist will do something stupid (turn in front of them, for example).

So take advantage of that. Looking at them, or at least making them think you are, creates a "communication" between the cyclist and the motorist. In truth it already exists, although neither side sees it that way. So take the lane, and when a car approaches, turn your head and let them know you are aware of them. This places the same onus on them.