(Note: a lot of the research with infants I’ve been writing about has been done with normally-hearing infants. Although there’s a lot of great research on children with Cochlear Implants, I’m finding that there’s less research on children with mild hearing losses, especially for infants and in interesting areas like music. So, I end up writing about studies that have been done with normally-hearing infants, and I’m really not sure how they translate!)
It’s been clear since T was just a few weeks old that he loved hearing me sing (this was a surprise to me, since pretty much no one else enjoys hearing me sing :)). Since then, I’ve sang to him A LOT – I sing when I play with him, when he’s cranky in the stroller or carrier, lullabies at bedtime, etc. I started wondering what research has been done on singing to babies, so I did a little searching.
One interesting question is whether/how we change how we sing when we sing to a baby compared to singing to an adult or to no one. It’s pretty obvious that people talk to babies differently than they talk to adults – the typical “baby-speak” is called “infant-directed speech” and it has a lot of potential benefits for babies to acquire language. Infant-directed speech is usually characterized by slower speech, repetitiveness (e.g., “look at the doggie! the doggie says woof! hi, doggie!”), higher pitch, and more pitch variation (i.e., MUCH less monotone than when talking to adults). This probably helps babies learn new words and understand the structure of language (e.g., the concept of phrases and sentences) by helping them focus their attention on particular words or groups of words by repeating and emphasizing them.
But do adults sing differently to babies than they do in their absence (even when singing the same song)? This is an especially interesting question, because many of the ways we change our speaking when it’s directed to a baby aren’t easily done in singing – for example, a particular song has constraints on pitch (based on the tune of the song) and rhythm, so it’s harder to vary pitch and rhythm when we sing and still maintain the song. But,it turns out that, similar to infant-directed speech, adults sing differently when the singing is directed to a baby! Studies ( and ) have shown that when we sing to babies (rather than singing the same song in their absence), we sing with a higher pitch (just like in infant-directed speech) and with a slower tempo (also like in infant-directed speech). And, even though mothers tend to sing more to their babies than fathers, fathers show the same pattern of singing in a higher pitch and with a slower tempo, so there may be something intrinsic about the characteristics of infant-directed singing. (See )
And, it turns out that the way we change our singing when it’s directed to a real, live baby and not just an empty room is pretty robust – adults listeners are really good at identifying instances in which another adult was singing to a baby rather than to an empty room – that is, which songs were “infant-directed.” (See ). The adult listeners tended to say that the “infant-directed songs” were sung with a “more loving tone of voice.” ().
I tried to think of whether I sing differently when I’m singing to T than when I’m singing by myself, and it’s hard to say, mostly because I rarely sing if it’s not to T 🙂 But, I wouldn’t be surprised if I sound more loving when I’m singing to T than when I’m singing by myself!
On a totally unrelated topic, another interesting study that I came across looked at the effects of moms singing on their babies’ arousal levels as measured with cortisol in saliva (). They found that babies (averaging 6 months in age) who had relatively low cortisol levels initially (for example, if they weren’t paying attention to anything in particular and were sort of just chilling) had an increase in cortisol after their mom sang to them for 10 minutes – that is, they were more aroused after hearing their mom sing and more in a “playtime” state. Conversely, babies who had higher initial cortisol levels had a decrease in cortisol after their mom sang to them for 10 minutes – that is, they went from a more aroused state to a more chilled out state after their mom sang to them.
This was interesting to read, because I’ve definitely found that my singing to T can have totally different effects on him, even singing the same song! Sometimes, he’ll get really excited and wound up and ready to play, and other times, he’ll totally relax and often, will get kind of drowsy.
 Trainor, L.J., “Infant Preferences for Infant-Directed Versus Noninfant-Directed Playsongs and Lullabies.” Infant Behavior and Development. (19) 83-92 (1996). (full text here)
 Trehub, S.E. et al. “Mothers’ and Fathers’ Singing to Infants.” Developmental Psychology. Vol. 33, No. 3. 500-507 (1997). (full text here)
 Shenfield, T. et al. “Maternal Singing Modulates Infant Arousal.” Psychology of Music. Vol. 31, No. 4. 365-375. (2003). (full text here)