Dog identification process

This is my very smart baby sister naming all of us! Of couse, although she's smart, she still needed some prompting sometimes.




I think my baby sister can sorta recognise my big brother herbie sometimes. Sometimes when she sees his photo, she will go 'Er-Bie!' but sometimes she just says dog. My M have been trying to tape her saying 'Herbie' but she's not always so cooperative. I wonder how she knows which is my big brother herbie since my M only showed her a few pictures of herbie.