We can't help it -- we see an infant and all of a sudden we're speaking in high-pitched, sing-song tones, cooing and babbling to the little bundle of joy. Though this baby talk may get on the nerves of those around us, babies love it and will pay more attention if you use it.
A 2011 Harvard study showed that 5-month-old infants look at and pay more attention to adults who use baby talk when speaking to them. Even after the talking is done, the infants had learned to prefer those adults who used baby talk. Researchers believe that babies use baby talk as a social cue: "This cue allows infants to focus their attention on individuals who are more likely to talk to them, and attend to them, and thus provide optimal care and opportunity for learning," says Adena Schachner, a Harvard psychologist and lead author of the study.
Now, You're Speaking My Language
Another study from the Harvard baby lab by psychologist Elizabeth Spelke found that by 10 months old, infants learn to prefer the people and things discussed in their own language. When researchers had two adults introduce two different toys, one in the infants native tongue, another in a foreign language, the babies looked longer at the adult speaking their language. When given a choice of toys to play with, the babies also tended to play with the toy they had seen the native-speaking adult hold.
This study suggests how strong our natural tendency is to prefer our "in-group" – those individuals who share our language, culture and as some infant studies have found, our physical appearance and skin color. Researchers believe these tendencies manifest themselves again in how children learn how to fit in to their social group as they grow older. When a similar experiment was done with toddlers, the toddlers were more likely to give a toy to the adult who spoke their language when given the option to give a "gift" to one of the two adults in the videos.
Babies Appreciate an Emotive Tune
As early as 9 months, infants can tell the difference between a happy song and a sad song, according to a 2008 study from Brigham Young University. Before infants learn to understand language, they use tone and emotion in the voice to derive meaning. This sense seems to carry over into recognizing the tone of musical selections, according to this research.
Researchers played three excerpts of happy instrumental music to 9-months-olds, repeating the excerpts until the infants appeared bored and looked away. If the researchers then played new happy songs, the infants did not regain interest, but when sad instrumental excerpts were played, the infants perked up, recognizing that they these songs were novel and different from the past selections.
In a news statement at the time, Brigham Young music professor Susan Kenney weighed in on this finding: "The happy songs were all in major keys with fairly short phrases or motives that repeated. Four of the sad songs were in minor keys, and all had a slower beat and long melodic rhythms," she said.
That infants can notice those difference so early in life is "fascinating," she said.