Psychologists reported Wednesday in the journal Current Biology that dogs do pay attention to the meaning of words. And they process that information in a different part of the brain than where they process emotional cues in speech.
To figure all that out, graduate student Victoria Ratcliffe at the University of Sussex in England set up a clever experiment. She brought 250 dogs into the lab. And then for each one, Ratcliffe put a speaker on either side of the dog’s head. Then she played the command “to come” out of both speakers, at the same time. At first, the command sounded normal. It had both meaningful words and emotional cues in it. Then Ratcliffe started to manipulate the speech in the command. In some instances, she removed all the inflections in the speaker’s voice. In other instances, she kept the inflections in the speaker’s voice but removed the words (or replaced the words with gibberish). For each command, Ratcliffe recorded which way the dogs turned their heads — toward the left speaker or toward the right speaker. Even though both speakers were playing the same sounds, a clear pattern emerged.
When the dogs heard commands that still had meaningful words in them, about 80 percent of the animals turned to the right. When they heard commands, with just emotional cues in them, most dogs turned to the left. That result sounds simple. But Andics, who wasn’t involved in the study, says the findings show something surprising: “That dogs are able to differentiate between meaningful and meaningless sound sequences.”