Misty is 19 months old, we took her to puppy classes & training classes for almost a year where she was socialised with all manner of other breeds, including hoomans

.
Now the thing that has me puzzled is that apart from our Collie x and my parents' Border terrier, she shows no interest what so ever in other dogs unless they happen to be Cockers.
If we should chance to meet another Cocker whilst out & about then everything has to stop while Misty goes to chat/sniff/play and if the next dog that comes along is not of the Cocker persuasion she won't even check her pace.
Same thing goes for people, she's completely uninterested in them unless they happen to be owned by a Cocker, then they are worth an acknowledgement.
She's not the least bit aggressive or stand-offish and doesn't appear to be anxious around dogs or people. She does get uncomfortable in crowds but I guess being 14" tall can do that to you.
George, our Collie x is completely different, he's a dog's dog, any strangers, canine or human, have to be checked out.
So I am wondering if this is common behaviour for a Cocker.