Entrainment : The universal law of harmony
As
discussed in the last chapter on
Brainwaves Frequencies, in
order to understand how Brainwaves are altered, we need to answer
following two
questions :
(1) How any external sound can alter our brain wave frequency? We listen
so many sound everyday. All of them must have an effect on our
brainwave. Then how come a particular sound of a particular frequency
will bring change in our brainwave's frequency?
(2) The frequency of
alpha, theta and delta are in the range of 1 to 13 Hz whereas human ears
are capable of listening to sounds only within the frequency range from
20 to 20,000Hz . So how can we listen an external sound that produce an
effect within 1 to 13 Hz to attain alpha, theta or delta level of
conscious?
Let us discuss these
questions one by one.
First of all, we
need to understand how an external sound can alter our brainwave's
frequency.
An external sound
alter our brainwave's frequency with the help of a simple natural
phenomena known as 'Entrainment'.
Please notice the spelling: It is
NOT
: Entertainment
It is
'Entrainment'
Entrainment is
defined as “a synchronization of two or more rhythmic cycles”
When two closely
related rhythmic cycles interacts with each other, they synchronize with
each other resulting in the conservation of energy. This is known as
Entrainment.
It is actually a
very common phenomena. Let us understand it with some real life
examples.
Entrainment was
first of all discovered by a Dutch scientist Christian Huygens in 1665
(it is that old !). One of the experiments that led to this discovery
was when Huygens set up a room full of pendulum clocks and got them all
started one at a time. He found that when he came back to the room a day
later, the sway of their pendulums had all synchronized. From this, he
extrapolated that entrainment represented the phenomena of
synchronization of closely related rhythmic cycles on their interaction
with each other to conserve energy.
So the principal
behind entrainment is very simple and has universal appeal :
"Any two vibrating
bodies will entrain if exposed to each other for long enough"
i.e. they will
synchronize if exposed to each other for long enough".
It’s true of clocks
and electric driers sitting in close proximity to each other; it also
describes the way musicians manage to play in time together in groups,
the way women’s menstrual cycles fall into synch when they live with one
another, and the way our body systems interact.
Within our bodies,
our various rhythmic systems never fight each other—they always fall
into synchronized rhythms—and a lack of synchronization, like in the
case of a bad heart valve that is not quite timed to the flow of blood,
leads to sickness. It also seems to be the case that these body systems
entrain, become synchronized, to the environment, to its oscillating
features. There is overwhelming evidence that circadian rhythms (our
biological clock) keep us entrained to the rhythms of the earth relative
to the sun, and that various systems within our bodies entrain to
repetitive stimulation. Other examples are the way that two people
walking next to one another will fall into step with each other, or the
way that people clapping in a full room will synchronize their claps
given enough time.
Entrainment and Brainwaves
So what actually
happen in the case of brainwave is that an external audio stimuli
(specialized sound with a particular frequency) is repeatedly played
which result in the entrainment of that brainwave with the external
sound. As this process is continued for sometime, the brainwave is tuned
to the frequency of external sound and thus achieve the particular
frequency level of that sound (alpha, theta or delta). This is known as
brainwave entrainment.
This
entrainment of
brainwaves is also called as Frequency Following Response
(FFR) in
many literature.
So the methodology
of brainwave entrainment is very simple. Just listen to the sound of
your desired frequency using headphones and soon that sound will entrain
your brainwaves to its own frequency level. For example, if a person is
in beta stage (highly alert) and a stimulus of 10Hz is applied to
his/her brain for some time, the brain frequency is likely to change
towards the applied stimulus. The effect will be relaxing to the person.
This is what we call called the frequency following response.
When the brain's
state is close to the applied stimulus, entrainment works more
efficiently. Thus, when doing a sweep from one frequency to another, the
starting frequency should be as close to your current brain state as
possible. The sweep speed should be such that your brain's state changes
steadily with it, so that the difference never gets very large. In
practice, it is difficult to determine your brain state without extra
equipment (like EEG devices). However, you can quite safely assume that
during the day your brain is in the beta stage (about 20Hz) and you can
start the sweep from there. If you are already somewhat relaxed, you can
use a start frequency of 15Hz or a few Hz lower.
So this is all you
need to know about brainwave entrainment, the method of altering your
brainwave frequencies.
However, we still
need to answer another important question.
From where are we
going to produce these specialized sounds with a frequency range of 1-20 Hz and
how we can make them hearable to human ears when it can only listen the
sounds of the frequency between 20-20,000 Hz ?
The answer to this
question lies in a specialized sound known as Binaural beats.
Binaural Beats
