I think watching her clips has improved my observation of Penny's behaviors. Yesterday I posted about her walk with a young puppy, and the owners of the puppy sent me the following clip. (I'm sorry it's so small, but I don't know how to make it larger. If you click on the square in the bottom right corner to make it full-screen it's a little easier to see.)
When I look at what Penny did after the pup dropped onto her stomach nearby, I see:
Penny looked at the puppy.
She looked away.
She looked back at the puppy.
She looked at the pup again.
The humans attracted the pup's attention with a twig and then both dogs came back to us.
I thought perhaps the looking away told the pup Penny was higher in status and didn't want to be bothered by a 'little kid'. The yawn might have been an indication that she wasn't going to attack the pup. I found this paragraph on About.com Dogs
Yawning is a type of appeasement gesture, something also referred to as a calming signal. Dogs yawn to deflect a threat. If a person or another animals approaches a dog, that dog may avert his gaze and yawn. It's a dog's way of saying that he feels threatened or anxious, but that he is not going to attack. Dogs use this type of body language to avoid conflict.
That implies that Penny might have felt uncomfortable with the puppy nearby, but I don't believe this was the case.
On the other hand...
three humans were staring at the two dogs, all three humans frozen in place with their mobile phones (cellphones) held high. Who wouldn't be a bit uncomfortable with the paparazzi crowding around?
I'm looking forward to our next outing together. Puppies change so quickly at this age that we'll probably have quite a different interaction.