Judy
Plantinga
Ph.D.
candidate, Department of Psychology, Neuroscience &
Behaviour
McMaster
University
1280 Main St. W.
Hamilton, Ontario
L8S 4K1
(905) 525-9140 ext 27114
plantija@mcmaster.ca
My Research
Are infants absolute or relative pitch processors?
As a graduate student in the Auditory Development Lab, I am interested
in the development of pitch perception in infants. One
of my studies, published in the journal Cognition,
looked at whether infants process melodies in terms of
relative pitch and/or absolute pitch. As adults, we
primarily use relative pitch information when processing
melodies. We easily recognize a song such as "Happy
Birthday" as the same song each time we hear it, even if
it is not sung in the same key. However, we do not
usually use the absolute pitch information. That is, we
are not very good at determining if a familiar song is
sung in the same key each time we hear it. Our studies
have shown that 6-month-old infants process pitch in a
similar way to adults. After listening to a melody for 7
days so that it becomes familiar, 6-month-olds prefer to
listen to a new song over the familiar song, even if the
key of the familiar song is different, demonstrating
they are using relative pitch information. The absolute
pitch information does not seem to be salient for
infants, as they do not prefer to listen to the familar
song in a new key, over the familiar song in the same
key. I am now interested in understanding pitch
perception in 2-month-old infants. My study with
2-month-olds was the first to show that 2-month-old
infants can remember a song they just heard. I am now
looking at whether 2 month olds use relative or absolute
pitch information to process music. Below is an example
of a 2-month-old being tested.
Infants' memory for single notes
Most adults cannot remember the pitch of a single tone for very long, and the presence of interference reduces performance in pitch matching tasks. I conducted a study using a conditioned head-turn procedure in which infants were rewarded for responding to a change in the pitch of a repeating tone to determine if infants memory for pitch is similar to adults. I found that 6-month-old infants can remember the pitch of a tone for at least 2.5 s but that, like adults, their memory is disrupted by the presence of tones interpolated between repetitions of the tone-to-be-remembered. As well, as the number of interference tones increases (0, 3, 5, 15) infants' performance decreased with their performance at chance with 15 interference tones. This suggests that for 6-month-old infants, memory for the absolute pitch of isolated tones fades rapidly, as it does for most adults. Below are examples of the stimuli we used.
3 interference
15 interference