Animals talking to people? That’s been a long-cherished fantasy for millennia.

Only now the question is seriously being asked as PBS’s Wednesday NOVA special “Can Dogs Talk” examines the scientific evidence by exploring the viral social media  phenomenon of “button dogs” who appear to use recorded sound buttons to communicate.

We see scientists – in Budapest, Cambridge, San Diego and Des Moines – try to find the answer whether “talking” dogs are actually communicating their thoughts and desires with us.

“As soon as I heard about it, I thought it’s a fantastic film to make,” director Olly Bootle said in a joint virtual interview with producer Kirstie McLure. “Because everyone loves and wants to watch stuff about dogs – and this subject has already gone viral on the internet.

“That’s where this documentary comes in: To look at what is true, what is actually real. Or is it just nonsense? Just people wanting a big following on social media manipulating clips to make some money?”

As to how they ended up with this “Dogs” list, “Hungary was easy,” Bootle said, “because Budapest is one of the world’s leading canine cognitive research centers. That was a no-brainer.

“San Diego, of course, Dr. Federico (Rossano of UC-SD) is based there, the lead researcher on the study we were looking at. And Cambridge is close to where I’m based in the UK.

“Then we went in the States where the ‘star dogs’ are. These dogs are doing things with buttons that make you go ‘Wow! I want to know more about them and about what’s really going on.’ We were led by where the interesting scientists and the interesting dogs were.

As for choosing which dogs, they had to able to offer insight into the science.

“In terms of the millions of dogs, some of them don’t even get off the starting blocks. I mean,” McLure said, “some dogs just go nowhere.”

The prime researcher Dr. Rossano “has got thousands of dogs he is gathering data on. But as he’ll explain and what you can see is if, for instance, a dog has 10 buttons and it presses each of those 10 buttons exactly the same number of times, you know that that dog is likely just pressing the buttons randomly.

“It tends to be when they skew towards preferential buttons that you know they’re actually choosing certain buttons over others.

“So Federico helped narrow down slightly the field, because then we know which dogs are potentially doing something more interesting than just randomly hitting buttons.

“He’s able to see those patterns of which dogs are not just spamming buttons but which are using them meaningfully and was able to point us to those dogs.

“And the experiments we showed were all verified.”

NOVA’s “Can Dogs Talk” airs on GBH Wednesday at 9 p.m.