When Greta earned her Ph.D. 13 years ago, Jim was two and a half years old, and Nora was just 10 months old. Jim knew a few words, and Nora couldn't talk at all. You might think a baby as young as Nora wouldn't have an appreciation for music or dance. If you can't walk, what good is dancing?
But babies -- and Nora was no exception -- love to be bounced. Bouncing her on your knee would elicit peals of laughter. Is this love of rhythmic bouncing somehow related to an appreciation of music?
Jessica Phillips-Silver and Laurel Trainor developed an ingenious study to see if babies even younger than Nora in this picture could appreciate musical rhythm. Seven-month-old babies sat on experimenters' laps for two minutes while a simple rhythm was played:
Half the babies were bounced every other beat, and the rest of the babies were bounced on every third beat.
Then the babies were allowed to control the music themselves, based on where they looked. A light flashed, signaling the music was ready to start. The music started as soon as they looked at the light, and stopped when they looked away. Half the time the music was accented in the same pattern as the babies had been bounced earlier, so when the babies had been bounced every other beat it sounded something like this:
The other half the time it was accented every third beat:
So which music did the babies play longer? Here are the results:
The first two columns show the results of the initial experiment. Babies listened longer to the music that matched the bouncing pattern they had been exposed to previously. The experiment was repeated with the babies blindfolded during training, to make sure that it was the motion of the baby and not the visual stimulus of the "world" bouncing up and down that cause the effect. The results were the same. Finally, it was repeated once more when an experimenter bounced with the music as the baby watched. In this case babies expressed no preference.
Phillips-Silver and Trainor argue that this illustrates that there's a strong connection between body movement and rhythm even in babies as young as seven months old. So something like an appreciation for dance develops before babies can walk or talk!
Phill-Silver, J., & Trainor, L.J. (2005). Feeling the beat: Movement influences infant rhythm perception. Science, 308, 1430.
I wrote a critique of this experiment a year ago. In a nutshell, rhythm and meter have much more complexity than many psychologists think.
Interesting observations, Scott. It's interesting to me that the bouncing still results in an effect, despite the problems with the training stimulus. Do you think that this could mean infants might also detect a difference even in the "experimenter bounces" condition?
I think it is possible that a bigger affect could be found if they had better training stimuli. If it was clear that the bouncing didn't match the rhythmic patterns, then the babies might listen even less. So, yes it is possible that the experimenter bounce condition could have a significant difference.