The quick blurb I read said they gave Koko the kitten to test her maternal instincts.
the kitten was to big to be used as floss
God bless Koko but didn't she lie to her handlers about pulling a sink off the wall. She seemed to be as surprised as the handlers.
The word “seemed” is the big word.
There were cameras in the place so they knew of course, even without looking at the camera stuff that Koko did it.
But she lied....Koko seemed very human at the time!