There are lots of people who, with training, can identify musical notes when they know the starting point — when they hear a song starting with “C,” they can name the rest of the notes in the song. But much rarer is the ability to identify musical notes without any context. This is what people are talking about when they talk about “perfect pitch” or “absolute pitch.”
Let’s do a quick test to get a rough sense of how many CogDaily readers have absolute pitch. Listen to this note:
Now, what note is it?
Obviously these results won’t be perfect, but they should give us a general idea. I’ll give the answer below so you can see how many people got it right.
But what is the nature of absolute pitch? Do people with “absolute pitch” ever make mistakes? Does the ability change as we age? A team led by E. Alexandra Athos recently published the results of the largest-ever study of absolute pitch. They collected data from over 2,000 individuals, 981 of whom were defined as having absolute pitch. They’re still collecting data online, and you can participate — even if you don’t have perfect pitch. So what did they find?
First of all, there was a dramatic difference in ability between people who have absolute pitch and those who don’t. People were asked to name 36 random notes generated by a computer (the “pure tone”), and 36 random piano notes. This graph shows their scoring:
You might expect scores on piano tones to be the same as pure tones. In fact people tended to score better on piano, which is why most of the points on this plot appear above the diagonal line which represents equal scores on both tests. The gray box in the lower left represents where you’d expect 95 percent of the scores would fall if the results were purely due to chance — and there’s a large group of people scoring in this range. The other large group is in the upper right — indicating nearly perfect scores on both tests. For the purposes of this study, anyone scoring to the right of the gray vertical line representing a score of 24.5 on the pure tone test was counted as having absolute pitch.
But with so many people participating in the test, the researchers could also see how scores corresponded to age. This graph shows the average scores for each age range among those passing the test:
The scores declined with age. Note too that 60- to 70-year-olds didn’t even average 24 correct. Wasn’t 24 supposed to be the cutoff for “Absolute Pitch”? Actually the researchers gave credit of 0.75 points for an answer that was one semitone (a sharp or a flat) off. This allowance helped them make an additional observation: when these answers were scored slightly differently (-0.5 for an answer one semitone flat [low], +0.5 for an answer one semitone sharp [high]), a pattern emerged:
Rarely were mistakes made in the flat direction, and responses became progressively biased towards “sharp” as respondents got older.
What’s more, there was a pattern involving which specific notes were incorrectly identified. Take a look at this graph of deviation from correct responses in pure tones:
G# was the note most often misidentified as sharper. A# was the only note misidentified as flatter. The note that’s one semitone sharper than G# is A. The note that’s one semitone flatter than A# is also A. Since respondents with Absolute Pitch are rarely off by more than a semitone, this means that A is guessed more often than any other note.
A also happens to be the note that orchestras use to tune before concerts. But not every orchestra uses the same value of A — some are slightly off of the standard value of 440 Hz for tuning a piano. Some ancient music orchestras tune A at 415 Hz — equal to the standard piano value for G#.
Athos’ team speculates that people with absolute pitch have accommodated to a wide variety of A-values as a result. Over time, this has led to a perceptual magnet effect — the same effect we discussed a few days ago on Cognitive Daily. The perceptual magnet causes people with Absolute Pitch begin to accept G# values as equivalent to A, just like it causes people to hear the Swedish “y” sound as an English “ee”.
But the perceptual magnet doesn’t explain the gradual increase in “sharp” responses over time. The authors believe that this change may be due to a physical problem with the ear over time. It’s likely that everyone’s ears start sensing pitches as “sharper” over time — they just don’t notice it because they don’t have Absolute Pitch.
So, how did you do on our little one-note test? The note in the recording is a G-sharp (we did an initial survey where the note was an E. Now we’re collecting more data).
Athos, E.A., Levinson, B., Kistler, A., Zemansky, J., Bostrom, A., Freimer, N., & Gitschier, J. (2007). Dichotomy and perceptual distortions in absolute pitch ability. PNAS, 104(37), 14795-14800.