This article will discuss why dance has a rhythm and explores why so many scientists are able to describe it with such precision.

Dance requires rhythm and musicians must know it. In this video, get a sense of why musicians have a hard time describing what dance feels like.

Why does dance have a rhythm?

A human responds to visual cues about time and movement. A rhythm defines and guides the movements that dance requires. Without a rhythm, dance would just be an absence of movement.

The time scale is different from that of the brain. A traditional approach to studying the structure of the brain simply considers two scales: the timescale of the cell and the timescale of the brain.

The scientists involved in rhythm research, however, look at the roles of both scales.

The body and the brain are aware of time in different ways. The body moves at a faster rate when it is engaged in a rhythmic activity.

The brain lives at its own time scale, not the body's. On the other hand, the body moves at the same timescale as the brain, and this perception can be changed.

If the brain is stimulated with a special type of sound and subsequently the body, it can feel as if it moves faster than the body actually moves.

This is called phase tuning. The body changes its speed to the brain, but the brain does not change its time scale.

Lori Kegel-Rothschild and Jack Grossberg developed a model of rhythm that includes both the size and speed of the body and the time scales of the brain.

When the time scales differ, the body perceives itself as moving faster, with a faster beat. The higher the difference between the two time scales, the faster the beat.

The beat can be changing over the course of a song, as it transitions from one section to another.

The importance of creating a rhythmic structure:

According to their model, movement has a three-step process. First, the brain registers the visual cues. Second, the body then responds by adjusting its speed.

The final step involves movement. The body follows the original cues and then goes back to the original speed.

This process is known as rhythmical spacing, where the periods of the movement are in different ratios.

The timing and changes in the timing of the body's movement create the sensation of a beat. The brain combines these sensations to create the rhythm.

How to explain rhythm:

Sometimes, scientists combine the model of Kegel-Rothschild and Grossberg with research in biology. In this case, the two areas of science come together to explain how the heart beats and the air rushes out of the lungs.

The structure of the heart

A cardiac arrhythmia, or an irregular heartbeat, happens when the chambers of the heart do not have enough blood to properly beat.

The heart rhythm, which allows it to perform normal functions, is controlled by the brain. The structure of the heart regulates blood flow and allows the heart to beat, which contributes to a constant flow of blood through the body.

The gas exchange in the lungs

Both the number and the speed of the blood cells circulating in the blood—the oxygen-carrying red blood cells and the carbon dioxide-carrying white blood cells—are controlled by the body.

When the body needs to breathe in oxygen, the lungs expand, opening up the inside of the chest. When the body needs to breathe out carbon dioxide, the diaphragm and other muscles in the chest contract and the lungs deflate.

All of these changes occur in just 0.1 seconds. The heart beats twice per second to produce these changes.

In summary, the combination of the body and the brain creates a rhythmical structure of rhythmic space and time in the body, which we can study by using this model.

A model of rhythm that works!

The current rhythmical spacing model of Kegel-Rothschild and Grossberg uses the visual cues that we are all familiar with.

However, these cues can be altered by different timescales in the brain. If we put in an oscillator to produce these visual cues, we can change the perception of the beat.

In our review article, we included studies that show that many people believe that they can feel different types of music based on the space and time they believe that the rhythm is occurring.

If the time scale of a sound is more regular than our perception of time, we think that we are perceiving it as being "fast" or "slow," depending on how long the duration is.

These differences can result from the time scale of the brain, the time scale of the body, or the rhythms of the stimulus. The model of Kegel-Rothschild and Grossberg provides an explanation for all of these factors.

Based on this model, we can use the relationship between the different mechanisms in the brain to explain how music listeners can hear a beat in time to the music.

Take, for example, a study in which people were asked to listen to a "fast" and a "slow" beat in time with the music. One of these was 5.1 seconds, which is very irregular. The other was 4.95 seconds, which is slower.

Those who experienced the 5.1-second beat perceived it to be the faster of the two sounds. This suggests that it is not time, but the perception of time, that differentiates the perceived beat from the actual beat.

In this way, we can predict the possibility that two similar sounds, even if they are produced using different techniques, can still produce a beat that people perceive as different from a "fast" or "slow" sound.

Combining the model with music theory...

In recent years, scientists have made further advances in our understanding of how the brain processes music.

New technologies and approaches, such as magnetoencephalography and electroencephalography, allow for clearer recordings of the brain.

These techniques have revealed that the brain is capable of using a variety of mechanisms to form a beat, depending on the context.

As such, they are now useful tools to enhance understanding of music. Researchers are now able to use these techniques to understand the beat from different sources, such as a speaker, an electrical signal, or even the heart.

Therefore, music scientists are able to combine different physiological processes, such as movement and breathing, to study how the brain processes rhythm.