[a] At first, Dr. de Mouzon and her team were worried that the cats weren't reacting at all. But then they studied film recordings of the encounters.
[b] Cats are often so stressed by being in a lab that meaningful behavioral observations become impossible. And forget about trying to get a cat to sit still for an M.R.I. scan to study its brain function.
[c] So the researchers for the latest study went to the cats' homes and played recordings of different types of speech and different speakers.