That is indeed the question. In my research there is little direct
evidence for the effectiveness of Sound & Light entrainment devices, but
quite a bit of evidence for the effectiveness of Neurofeedback devices.
For example, see the collection of papers & abstracts at:
http://192.147.157.51:8000/galaxy/Medicine/Therapeutics/Alternative-Medi
cine/Biofeedback.html
and:
http://192.147.157.51:8000/galaxy/Medicine/Therapeutics/Alternative-Medi
cine/Biofeedback/Neurofeedback.html
or do a Medline search on "Neurofeedback".
These studies collectively show a number of correlations between certain
observed brainwave states (via EEG) and certain observed
behavioral/physiological states. Further they show that with training
subjects can learn to directly modulate their own brainwave activity,
and that this can have benefits in directing attention, augmenting
visual ideation, controlling pain, eliminating stress, dealing with
addiction, etc..
Sadly studies to date have been focussed on eliminating "pathologies"
such as Attention Deficit Disorder or addictive behavior and relatively
little experimental work has been done on the potential of this
technology for augmenting human capabilities beyond societal norms.
However if I'm allowed to step into the realm of anecdotal evidence, er,
I mean postulated models of attentional processing :), then I'd add the
following points:
* EEG measurements of those with a fair bit of training in Neurofeedback
or a fair bit of experience with Mind Machines look quite similar to
those of extremely experienced meditators, either in the Vipassana
(insight) style of meditation, or the more-scientifically-studied
tranquility meditations, such as Transcendental Meditation.
* Some studies (I wish I could vouch for their accuracy - any comments
from the peanut gallery?) have found an extremely large IQ boost in
twice-daily practitioners of TM. 20 points on average if memory serves.
* Among ADD sufferers, studies of neurofeedback protocols routinely show
a 20-30 point IQ boost over a period of several months.
I would hesitate to take any one of the studies that show such drastic
benefits at face value, but similar results have been replicated by
numerous researchers. It's my hope that in the next few years we'll see
more research focussed on using these technologies to augment "healthy"
individuals rather than merely as corrective tools.
Finally, to come back around to Mind Machines (Sound & Light Entrainment
Devices), I should say that while there is little in the way of
published studies of their effectiveness, there apparently /is/ a
well-documented entrainment effect where brainwave activity falls into
cadence with rhythmic visual & auditory stimuli. The similarity between
the effects & observed EEGs of Neurofeedback subjects and meditators
suggests that a third entrypoint to the same EEG state (such as a Mind
Machine) would produce similar effects.
While not all of us can afford an EEG at home, most of us can afford a
small Mind Machine. Net, I'd advise you to try one out, perhaps
borrowing one before you buy, and experience for yourself how it affects
you.
mez