Absolutely not absolute pitch perception: but even people without perfect pitch can hear off notes

Cassie Jacobs. Most of us can’t tell one musical note from another – but is it because we can’t really hear the difference, or because our knowledge of musical structure is implicit? Recent evidence suggests that we can take advantage of a lifetime of experience with musical categories to identify whether a musical note sounds wrong.

Being hard of hearing and having given up the violin at the end of sixth grade, I have a hard time making and perceiving tones. It turns out that I’m not alone – many Westerners find that they fail to name the category a tone belongs to, either while learning foreign languages like Chinese, in which differentiation between tones is crucial to comprehension, or musical instruments later in life. To illustrate, you can revisit this earlier post here, which illustrates the tonal nature of Chinese.

Many skills are thought to be crystalized beyond a certain age, like language learning. Anyone who has started learning a language in high school can say how hard it is to get the sounds right, or learn that different words can change based on where they occur in a sentence. Tone perception in language processing is also a skill that seems to be best acquired early. Many languages like Chinese, Yoruba, or Cherokee use tones to distinguish words, and most learners of these languages who grew up speaking English find it hard to acquire them. Not only do English speakers find it hard to hear the distinctions, they also often fail to produce them as well.

The same thing applies to music. When we listen to a familiar song at a concert, we may know whether a note was played wrong, but may not be able to identify what was wrong with it. Because the song is familiar, we come to expect certain sounds at particular times and at particular notes, even if we could never play the song ourselves.

It is thought that only one in ten thousand people can recreate or name the musical notes played to them – those people are thought to have “perfect pitch”. Also known as absolute pitch, this ability is thought to be acquired only early in life.

Even listeners with perfect pitch show sensitivity to the listening environment—if they listen to distorted music, they are less able to identify out of tune notes than in a normal listening environment. It is reasonable that those of us who don’t have absolute pitch might also use the context when listening to music, and that we might also have something like absolute pitch.

More recently, researchers Steven Van Hedger and colleagues at the University of Chicago challenged this assumption that only a select few have the ability to categorize in-tune and out-of-tune musical notes. Their study, just out in the Psychonomic Bulletin and Review, tested whether people after a lifetime of experience with music have implicit, rather than explicit, knowledge of pitch. That is, even if we cannot name a tone spontaneously, maybe we still know something about it in a more tacit manner?

Some earlier studies had found that most people can identify whether a note is in tune or out of tune, at least when listening to songs they already know. There are rules and strong patterns that govern where notes go in Western music. For example, most music has a reference point of 440 Hz in what is known as “canonical tuning.”  Such a note sounds like this:

Van Hedger and colleagues conducted two experiments in the lab and on Amazon Mechanical Turk. The latter platform allows researchers and other groups to gather more data using many more participants than a typical study in the lab. Since undergraduate students are considered “weird” by most statistical standards, studying musical cognition outside the lab is especially useful.

In the first experiment, Van Hedger and colleagues recruited 102 participants from Mechanical Turk, of which nearly half (48) were self-identified musicians, and 101 undergraduates from the University of Chicago, of which 92 had musical training. Participants heard examples of notes that were “in tune”, which lined up with standard tuning practices, and “out of tune”, which had been shifted away from the standard to be between two standard notes. Participants then categorized 48 notes into these two categories. Participants in both in the online and laboratory experiments were able to distinguish in-tune and out-of-tune notes, with musicians being much better at discriminating the two categories than non-musicians, presumably because more practice with music and tuning enhances categories for what in-tune notes should sound like.

Experiment 2 looked at timbre—the quality of the sound that distinguishes different sources, like choirs from guitars, even when the notes are identical. Since we do not hear the full range of timbres in the world, hearing a tone from an unfamiliar instrument could hamper our ability to make musical judgments. Violins and pianos have familiar timbres, so participants in Experiment 1 may have relied on what they know about in-tune sounds for those instruments.

If perfect pitch does not depend on this information, but instead the actual tone, then participants should still be able to know what in-tune means, showing that this tone perception generalizes across categories of instruments. When participants in Experiment 2 listened to tones generated by a computer rather than real-world instruments, even musicians did not reliably distinguish in-tune and out-of-tune musical notes above chance. The unfamiliarity of the timbre or the tone’s source obliterated the distinction between in-tune and out-of-tune notes. So, when listening to an unfamiliar instrument, anything might count as in-tune until we experience that instrument playing songs. Once we have learned more about these categories, we can demonstrate something much more like absolute pitch than previously believed possible.

Our experience with the particulars of Western music seems to determine what we hear. Just like what happens with language, we find it harder to distinguish in-key and out-of-key tones when we don’t have explicit category labels. At the same time, this novel study shows that even people without perfect pitch have rich representations of musical notes that they have experienced throughout their lives.

Article highlighted in this post:

Van Hedger, S.C., Heald, S.L.M., Huang, A. (2016). Telling in-tune from out-of-tune: widespread evidence for implicit absolute intonation. Psychonomic Bulletin and Review, DOI: 10.3758/s13423-016-1099-1.

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