|Style over substance|
Brainwave woo is pretty self-explanatory: It refers to any woo surrounding the manipulation of brainwaves. Brainwave woo is like the less appreciated younger brother of quantum woo in that both are commonly shoehorned into any old pseudoscience to give it a veneer of legitimacy. Brainwave woo is a favorite of dirty effin' hippies, quacks, Deepak Chopra (but I repeat myself), and potheads.
 What brain waves are
Brain waves, officially called neural oscillations[wp], are patterns of brain activity repeated several times per second, which can be detected from the outside by means of equipment such as an electroencephalograph. Their functional role is still not fully understood.
For those not in the know, here are the basic categories of brainwaves:
- Delta (up to 4 hz): Sleeping, some attention tasks.
- Theta (4-7 hz): Drowsiness, inaction, inhibition in response to stimuli.
- Alpha (8-13 hz): Inhibition, relaxation.
- Beta (14-30 hz): Alertness, normal concentration.
- Gamma (31-100+ hz): More extreme forms of sensory stimulation, heightened concentration.
It is important to note that these frequency ranges are merely detected in certain regions of the brain (and rarely occur in multiple regions at once), more often than not, when a given person is in these mental states. This does not at all mean that you can make somebody slip into one of these states by forcefully inducing brain waves at these frequencies.
 Brainwave manipulation for fun and profit
Brainwave woo is usually based on the notion that there is an "ideal" or "higher" state of consciousness that can be activated by manipulating brainwaves. Alpha and theta waves are common choices, as can be seen from the prevalence of ThetaHealing, which is brainwave woo in overdrive, and the various woo surrounding alpha waves.
Products or techniques sold based on this idea generally claim to "adjust" your brainwaves to their "natural" or "heightened" state. This is based on the scientific concept called brainwave entrainment, where a periodic stimulus is provided that aims to bring electroencephalograph (EEG) readings into line with the period of the stimulus. Entrainment, however, does not have any lasting effect once the stimulus is shut off. Products based on entrainment usually make two fallacies:
- There are no "ideal" brainwaves that will make you super-smart, diligent, etc. There is no "higher" state of consciousness that can only be accessed through adjustment of brainwaves. This notion is not even wrong.
- Brainwaves are not uniform across the entire brain. EEG readings will differ depending on the area of the brain and will have different meanings in different circumstances. In other words, physiology is not that simple.
One particularly silly set of claims surrounding brainwaves is that because young children's brains tend to produce more theta waves, using entrainment products to increase theta waves will help you "find your inner child" or similar nonsense. In reality, it'll probably just make you drowsy.
Products that use binaural beats like I-Doser often base their claims on brainwave woo. They can, in fact, have a placebo effect, but it's much cheaper, just as effective, and more enjoyable to just play music that you find relaxing, exciting, or whatever depending on what kind of mood you're aiming for. Brainwave woo is also commonly attached to hypnosis, quack mental therapy and alternative medicine, meditation and other religious or spiritual exercises (higher states of consciousness, maaaan), remote viewing or telepathy (the idea that certain brain waves can allow for ESP), and drugs.
 Brainwave manipulation for evil
Since extreme low frequency radio waves cover the same frequency range as brain waves, some conspiracy theorists believe that they can therefore induce brain waves. This makes about as much sense as the notion that low-frequency radio waves can induce waves on a lake (they can't). Sensibility never stood in the way of a good conspiracy theory, though, and so poor old HAARP -- which produces such extremely low frequency radio waves -- is claimed to be a mind control device.
 See also
- See Scholarpedia's EEG entry for more on the actual science of brainwaves.
- Steven Novella takes on brainwave woo: Brainwave entrainment and marketing pseudoscience, Brainwave entrainment, a response, Neurofeedback and the need for science-based medicine
- DC celebrates pseudoscience, Scientific Activist
- Synchronized Spiritual Woo and Brainwaves for You, Mind Tweaks