[edzillion]

There has been some fascinating work on human canine coevolution over the past years - I read a paper (sorry can't locate it now) that claimed that humans developed such distinct pupils due to it being so useful to survival for dogs to be able to see which direction a human is looking, for example in a hunting context. That one blew my mind.

[bitwize]

I heard that was so that other humans could see what we were looking at (though dogs may also benefit).

What I did notice was that dog sclerae are more visible than wolf sclerae, and I believe that to be for similar reasons, so a human can read where exactly the dog is looking.

What really blew my mind was learning that the "puppy dog eyes" look was due to extra orbital muscles that dogs have and wolves lack. Dog faces evolved to respond to human sensitivity to facial expressions.