It has determined a number of faces (as you would expect from any facial recognition software) but it has also figured out the names, despite me never having entered any
1Spooky. Maybe from Contacts, if they have photos attached. I can't test as I've had faces set up for a long time - since before it could be tied to Contacts– TetsujinMay 3, 2015 at 10:20
How did you get photos into the Photos app? Was it from iOS? Do you have faces in your contacts app on OS X? It's hard to guess from the scant details you've included.– bmike ♦May 3, 2015 at 18:21
photos are just from photostreams that have been created from iOS sources i.e. iphone, ipad. It's not possible that some of the faces exist as contacts as they are too young and thus have no phone/mail/other contact point, I have even checked the contacts app on the imac and they do not exist there– adolf garlicMay 7, 2015 at 19:36
It has access to the face data in your contacts, such as from syncing with Facebook. So, it's found similarities to those pictures.
I'm not on facebook and some of them are people too young to be online May 3, 2015 at 16:55