Yes that cat did notice the owner left, it looked right at the owner as she walked out the door and walked around the other person. The cat was also out of sight when owner came back and did look at owner, but felt comfortable enough to continue playing.the baby and dog both used their mom/owner as a point of reference. they know where they are the entire time. when the dog owners leaves, the dog eventually notices and runs to the door. the cat doesnt use the owner as a point of reference so therefore doesnt realize the owner left and didnt even realize the owner came back. the cat wasnt playing with the toy when the owner came in. it just didnt care. i dont own a cat so i cant comment on how it is in real life. i do find the study a little bias but interesting non the less. whether its true or not can be debated.
That experiment wasn't very good, they did not produce the same conditions for the dog versus the cat so you can't extrapolate from it. The 'stranger' played with the cat the whole time the owner was gone, while the dog was ignored by the stranger after the owner left. Also one cat and one dog is not conclusive of anything.
Since dogs are pack animals you would expect them to want to stick closer to their owners whereas cats have a much looser social structure so they may be more likely to range further and be less dependent on their owners. Cats also tend to be much more reserved so you can't necessarily expect a doglike reaction from a cat. Additionally many cats do not get out of the house with their owners very much, and placing them in a strange environment may have a different effect on them than it would on a dog as dogs are more likely to regularly be taken out to various places. This also means cats are also likely to react differently to their owners leaving them, since they generally are left at home whereas dogs may expect/want to go along.
Considering how differently my cats act with me and with other people, even people in my household and people who they know well and who also feed them (like my family, my petsitter and a friend who's known them since kittens and also sometimes petsits) I would say they are definitely attached and care if I'm there versus other people. They also greet me at the door when I come home. They don't greet my family members, even those who also feed them. Whenever I come back for a trip one of my cats is extra clingy for days after- he'll sit on my chest almost any time I'm sitting down, and put his front legs around my neck and cling on to me.
One of my cats is living with my brother now (because his cat and mine grew up together and Church was happier with Roxy than with my other cats) and he definitely knows me. Even though I only visit twice a year, he always greets me when I come from the airport and licks me, and he cuddles with me while I'm visiting which he doesn't do with my brother's friends who see him much more often than I do and feed/care for him regularly (when my brother is away for work which is fairly often). He will play with them and let them pet him but he acts differently with me. His friend even commented that he could tell Church was my cat because of how he behaved with me.