Discussion about Meter vs. Rhythm

In the study of musical time, London defined rhythm and meter as distinct but interacting dimensions of temporal experience. Rhythm involves patterns of duration that are phenomenally present in the music, determined by the interonset interval (IOI) between the attack points of successive events. By contrast, meter involves the initial perception and subsequent anticipation of a series of beats abstracted from that rhythmic surface as it unfolds in time.

The Psychological Distinction

The fundamental difference between the two is that rhythm involves the structure of the temporal stimulus, while meter involves the listener's perception and cognition of that stimulus. To categorize this relationship, London suggested that if meter is considered a "mode of attending," then rhythm is that to which the listener attends. While rhythm is physically present in the sound, meter is a perceptually emergent property that represents the listener's engagement with tones in time.

Meter as an Abstract Framework

Unlike rhythmic patterns, which consist of durations and "groups," the beats of a meter are idealized mental points in time that have no duration themselves. Meter serves as a temporal ground or a "self-generated" grid against which rhythmic figures are measured and understood. Key aspects of this abstracted framework include:

• Anticipatory Schemata: Meter is an entrainment behavior—a synchronization of biological activity with recurring environmental events that allows a listener to predict the timing of future events.
• Metric Malleability: Because meter is an abstracted construct, many rhythmic patterns are metrically malleable, meaning the same series of notes can be heard in different meters (such as $4/4$ vs. $6/8$) depending on the listener’s mental framework.
• Hierarchical Depth: While rhythm involves the "chunking" of events into motives and phrases, meter is hierarchical, organizing pulses into levels such as the tactus (beat), subdivisions, and measures.
  Interaction and Synchronization
  Meter and rhythm interact to create the "groove" or "feel" of a piece. Meter guides the motor behaviors of a performer, helping them play rhythms with the correct proportions and expressive timing. When a listener is entrained, their attention "moves with the music", allowing them to synchronize their cognitive processes with the physical rhythmic surface. London noted that while rhythmic patterns evoke metric responses, the abstracted meter also gives shape to the resulting rhythm through internal entrainment or externalized behaviors like foot-tapping.
  Ultimately, London argued that meter is not fundamentally musical in origin but is a peculiar instance of a general human ability to extract temporal invariants from the environment to organize sensory input.

Rhythm as the Temporal Stimulus

Rhythm is characterized by the patterns of duration that are phenomenally present in a musical sequence. These patterns are not determined by the literal duration of a sound (whether it is played short or long), but by the interonset interval (IOI)—the time span between the attack points of successive musical events.

Key aspects of rhythm as a stimulus include:

• Phenomenal Presence: Unlike meter, which is an abstracted framework, rhythm consists of the actual sound patterns occurring in time.
• Virtual Motion: Although musical tones do not physically move, rhythm acts as a stimulus that signifies virtual motion within "acousmatic space". This perception of movement is parasitic on our nonmusical engagement with sounds, where temporal regularities indicate motion in the environment.

• Density and Determination: A rhythmic surface can be categorized based on how much information it provides to the listener. A stimulus is metrically overdetermined if there are "too many notes" to correspond to every beat, requiring the listener to filter the information. Conversely, it is underdetermined if there are more beats in the meter than there are actual articulations in the rhythmic stimulus.

  “rhythmic surface” 用来描述音乐中实际发生的、感官可直接听到的节奏活动。具体而言，指的是“real-world timing of musical events”，由IOI构成。应该根据具体情境翻译成“节奏表层 / 音乐表层”，或者“感官节奏层”。与节拍进行对比的话，节拍是抽象的，节奏是具体的；节拍是“心理建构”，节奏是外部刺激。节奏表层具有主观上的可塑性，同一个表层（一串音符）可以根据听者的心理建构，被感知为不同的节拍。如果表层音符极其密集（音符数量远多于节拍点），听者需要“过滤”很多多余的信息去定位节拍，因此感知负担加重，这种情况就是“这个节奏表层具有metrically overdetermined”。与之相对的，表层音符太稀疏，听者必须自己在脑中进行“interpolate”，插值补全拍子，这种情况就是metrically underdetermined.

The Stimulus-Cognition Relationship (Meter vs. Rhythm)

London suggests that the relationship between rhythm and meter is one of stimulus and response. While the rhythmic stimulus provides the "invariants" (regularities), meter is the result of the listener's ability to entrain or synchronize their internal biological activity with those recurring environmental events.

Chapter 2&3 offer several insights into this interaction:

• Metric Malleability: Because rhythm is a stimulus and meter is a cognitive construal, many rhythmic patterns are metrically malleable. This means the same series of notes can be perceived in different metric contexts depending on how the listener chooses to organize the stimulus.
• Subjective Metricization: Human listeners often project order onto a stimulus even when it is neutral, such as hearing a series of identical clicks as being grouped in twos or threes; this is known as subjective rhythmization (or "subjective metricization").
• Metric Flux: The rhythmic stimulus can change over time—by adding or removing levels of subdivision—forcing the listener's metric engagement to be fluid rather than static.
• Ground vs. Figure: In the broader perceptual context, meter serves as the "ground" or stable framework, while the rhythmic stimulus serves as the "figure" that is understood against that ground.

Ultimately, while rhythm provides the physical data (the stimulus), the meter allows the listener to synchronize their perception with those rhythms as they occur in time, turning a series of tones into a structured musical experience.