New research shows babies have a handle on the meaning of different dog barks - despite little or no previous exposure to dogs.
Infants just 6 months old can match the sounds of an angry snarl and a friendly yap to photos of dogs displaying threatening and welcoming body language.
The new findings come on the heels of a study from the same Brigham Young University lab showing that infants can detect mood swings in Beethoven's music.
Though the mix of dogs and babies sounds silly, experiments of this kind help us understand how babies learn so rapidly. Long before they master speech, babies recognize and respond to the tone of what's going on around them.
"Emotion is one of the first things babies pick up on in their social world," said BYU psychology professor Ross Flom, lead author of the study.
Flom and two BYU students report their latest "amazing baby" findings in the journal Developmental Psychology.
"We chose dogs because they are highly communicative creatures both in their posture and the nature of their bark," Flom said.
In the experiment, the babies first saw two different pictures of the same dog, one in an aggressive posture and the other in a friendly stance. Then the researchers played - in random order - sound clips of a friendly and an aggressive dog bark.
"They only had one trial because we didn't want them to learn it on the fly and figure it out," Flom said.
While the recordings played, the 6-month-old babies spent most of their time staring at the appropriate picture. Older babies usually made the connection instantly with their very first glance.
Study co-authors Dan Hyde and Heather Whipple Stephenson conducted the experiments as undergrads and don't recall any babies getting upset.
"Many of them enjoyed it," said Hyde. "Others just looked."
"Infants are pretty cooperative subjects," Stephenson added.
The mentored research experience helped Hyde and Stephenson secure spots at prestigious grad schools. Hyde is currently at Harvard working toward a Ph.D. in developmental psychology. Fellow co-author Heather Whipple Stephenson recently completed a master's degree in educational psychology at the University of Minnesota.
"With this study, my favorite part was watching a somewhat zany idea grow into a legitimate research project," Stephenson said.