Brainwaves are a measure of the electrical activity of our brains. Thinking occurs when the cells in our brains exchange electrical and chemical signals. Brainwave activity indicates what is going on in the brain. The following table shows the common frequencies that we experience daily.

Brainwave Frequency State of mind
State Range
Delta 0.5-4 Hz Deep sleep
Theta 4–8 Hz Drowsiness and first stage of sleep –
suggestible state ideal for hypnosis and mind programming
Alpha 8-14 Hz Relaxed but alert – good for meditation
Beta 14-30 Hz Highly alert and focused- good for learning
and IQ development
Just as brainwave patterns measure a person's mental state, so we can alter brainwave patterns and thus influence mental states.

The Theta frequency dominates when we are drowsy, so entrainment at the Theta frequency induces drowsiness. It is said that half an hour of Theta entrainment can substitute for four hours of sleep. Alpha and Theta entrainment can also be a shortcut to meditation and mind programming.
The Dutch scientist Christian Huygens is credited with discovering entrainment. While working on the design of a pendulum clock in 1665 Huygens found that when he placed two clocks near each other on a wall at first the pendulums swung at different rates, but eventually they ended up synchronized, swinging together. The synchronization was perfect.

It was as if the pendulums were connected physically.
To view the pendulums swinging in unison go to

Entrainment is not just a phenomenon associated with physics, it is a universal scientific principle found in chemistry, biology, psychology, medicine, sociology, astronomy and other scientific fields.

Brainwave entrainment depends on a frequency following response, a naturally occurring phenomenon where the human brain tends to change its dominant frequency towards the frequency of an external stimulus, just as one pendulum synchronizes with another.

The effect that causes brainwave entrainment is a pulse of sound. A drumbeat is a pulse of sound. Drums have been used by shamans and others for millennia to induce trance states and altered states of consciousness. Light as well as sound may also be used in brainwave entrainment, but light is difficult to incorporate in, for instance, study routines which require reading. We use only sound, which can be incorporated into anyone’s study routine.

Binaural beats

A pulse is a rhythmic tone that turns on and off at a certain frequency per second. In order to entrain brainwaves the technology we use generates pulses of either isochronic tones or binaural beats. Binuaral beats are produced in the brain whereas isochronic tones are produced externally, like drumbeats. Binaural beats require earphones whereas isochronic tones do not. You will see a lot about binaural beats on the Internet.

A beat is interference between two sounds of different but close frequencies. Thus if a sound of 100 Hz is played into the left ear and another sound of 109 Hz is played into the right ear the resulting beat frequency is 109 – 100 = 9 MHz, a frequency in the low alpha range of brainwaves. All we need to induce beats in the brain is an iPod or other MP3 player and stereo headphones for binaural beats, headphones are not needed for isochronic tones though they may be used.

You can read about binaural beats on websites devoted to brainwave entrainment. Binaural beats may be over-hyped on the Web; some research indicates that binaural beats, which are produced in the brain, are not as effective for entrainment as isochronic tones. Binaural beats are very quiet. On the other hand binaural beats have been used successfully.

With binaural beats you cannot target each brain hemisphere separately, making dissociation and complex sessions impossible. We mostly use isochronic tones, arguably the most effective form of rhythmic stimulus. An isochronic tone is an evenly spaced tone-based pulse that turns on and off abruptly. Because the tones turn on and off so quickly they produce the strongest possible responses in the brain.

Binaural beats produce sine waves, not the simple, abrupt pulses of isochronic tones; binaural beats lack the clear on/off definition of isochronic tones. Also isochronic tones are usually more audible that binaural beats. This is why research indicates that isochronic tones are the most effective stimulus for brainwave entrainment.

Altered States

Robert Monroe popularized the use of binaural beats. Monroe founded The Monroe Institute after he started having out of body experiences (OOBE). A person I trust described OOBE to me. He was a British Army officer, Major ‘Bunny’ Austin, who was my commanding officer in the British Army.

Major Austin told me that he experienced looking down on himself being flogged, almost to death, on a flogging frame in a military square by his Japanese captors in World War 2.

According to Wikipedia The Monroe Institute “runs a Gateway Voyage program, a training course that uses binaural soundtracks to facilitate exploration and replication of specific altered states of consciousness.” Certainly Out of Body Experiences are mentioned extensively in Buddhist discussions of meditation, many texts describe meditators being able to be in ‘two places at once’. I have never experienced OOBE through meditation but I accept that others have.

Those many people who have used cannabis and other psychoactive drugs will have experienced altered states, though as John Lennon said after attending the Maharishi’s Transcendental Meditation course, “meditation is better than drugs”.

The head of the Zen Buddhist temple in Vancouver British Columbia stated that "(Monroe Institute) Gateway students can reach meditation states in a week that took [me] years of sitting" (Wikipedia). Brainwave entrainment is widely used as a means to achieve the benefits of meditation in a very short period of time.

There is a certain amount of mysticism and sensationalism associated with the use of binaural beats. There have even been reports in the tabloid media that binaural beats are an ‘electronic drug’ that may be potentially harmful to children. This is pure journalistic sensationalism. Binaural beats are safe.

Binaural Myths

There is a common misconception that binaural beats are the only form of brainwave entrainment. This is not true, any evenly-spaced stimulus can produce brainwave entrainment, even a drum or a metronome, a light flashing off the spokes of a wheel or the flicker of an electronic game.

I saw the following statement on a doctor’s (MD) website: “humans do not have a sense of hearing acute enough to hear the low sounds necessary for brain stimulation”. Though that doctor (I won’t identify him here ) presents himself as an expert, he is clearly confused. There is in fact a lot of confusion about brainwave entrainment and many other things on the “cesspool of misinformation” that is the Internet.

The befuddled doctor and other websites sow confusion about the alleged need for binaural beats to present stimuli below 20 Hz. The range of human hearing is 20 – 20,000 Hz.

Confused people, like this doctor, who do not understand the product they are selling, are mixing up Hertz (Hz) or cycles per second, and the pitch or timbre or volume of a tone. Clearly we can hear drum beats or a clock ticking or hands clapping at far lower frequency than 20 times a second as long as they are pitched loud enough to hear.

Try it, clap your hands once a second, that is 1 Hz; you will hear them clapping. According to the confused doctor you would not hear your hands clapping because you are clapping less than 20 times a second; he confuses pitch with frequency.

Brainwave entrainment is not new; scientists have been studying it for more than 70 years. However, only in the last two decades has neural science reached the exciting frontier it occupies today, with the realization of neuroplasticity of the brain. And only recently has medical science developed the capability, with EEGs and the far more sophisticated but much more expensive MRI scanners, to look at what is actually happening in a living brain and to provide neurofeedback.

Today we can use brainwave entrainment to induce those dominant brainwave frequencies that help raise IQ or facilitate learning. Brainwave entrainment can also be used to enhance creativity; I sit with my headphones on and a creative track playing when I write. Brainwave entrainment has a proven research record in enhancing learning and raising IQ significantly. It can work for you.

Copyright (c) 2011 Michael Petty. All rights reserved.

Author's Bio: 

Dr. MICHAEL PETTY is an authority on accelerated learning, IQ, Neuro Science and brainwave entrainment. He has a BA from Durham UK, an MA from Calgary and a PhD from the University of Wisconsin at Madison. He was a Canada Council Doctoral Fellow and his 1980 research on change in IQ scores, published in the British Journal Educational Research is still cited in Psychological texts. His latest book is Michael Petty, IQ Unlimited, Amazon Kindle. Visit Dr Petty’s website at