Or maybe the cats didn’t like the researchers. My cat does know his name and often will meow when called as a reply then come over to see what’s up.
When I was in high school we lived out in the country surrounded by an alfalfa field. I had a big grey cat named David. I could walk out on our back porch and call.....Daaaaaviiiiiddd a couple of times and you could hear him meowing every time I called him as he came toward me out of the alfalfa field.