Aggiornamento: 28 mar 2021
Jump to navigationJump to search A light and sound machine with headphones and strobe light goggles. A mind machine (aka brain machine or light and sound machine) uses pulsing rhythmic sound, flashing light, electrical or magnetic fields, or a combination of these, to alter the frequency of the user's brainwaves. Mind machines can induce deep states of relaxation,concentration, and in some cases altered states of consciousness, which have been compared to those obtained from meditation and shamanic exploration Photic mind machines work with flickering lights embedded in sunglasses or a lamp that sits on a tripod above your head or facing you. You then "Watch" with your eyes closed. The process applied by some of these machines is said to induce brainwave synchronisation or entrainment.
Mind machines include flashing light devices, which are similar to the Brion Gysin dreamachine in that both produce a flickering visual field. Unlike flashing light devices, the dreamachine can be used by several people at once, but has few, if any, technical features.
A Brion Gysin Dreammachine.
Mind machines typically consist of a control unit, a pair of headphones and/or strobe light goggles. The unit controls the sessions and drives the LEDs in the goggles. Professionally, they are usually referred to as Auditory Visual Stimulation Devices (AVS devices). Also mind machines are offered that can connect to the Internet for updates download of new session material.
One session normally takes between 15 and 60 minutes. During a session the user should lie relaxed, and place the glasses on the eyes, which should remain closed during the whole session. Many machines have pre-programmed sessions which vary in parameters like light brightness, audio pitch or beat frequency but also give the opportunity for the user to create a custom session. Typically one session consists of a series of segments. Within one segment parameters change in a constant way. Mind machines are often used together with biofeedback or neurofeedback equipment in order to adjust the frequency on the fly, while proof for their effectiveness is lacking.
Description of altered states
Light & sound mind machines can have various effects on the user. Most users describe seeing a flashing light, others perceive swirling patterns that have been compared to psychedelic light shows or fractals. A few users report seeing detailed, virtual reality like scenes. But also tactile and emotional changes are reported after a 6 Hz photic stimulation, as well as auditory hallucinations like binaural beats.
Changes in brain activity
Sessions will typically aim to address the target frequencies which correspond to delta (1-3 hertz), theta (4–7 Hz), alpha (8–12 Hz) or beta brain waves (13–40 Hz). Those frequency bands can be adjusted by the user based on the desired effects.
For relaxation, often a reduction from beta waves to lower alpha or theta frequencies is observed. It is aimed to reach a level of “slow alpha” (8 Hz). Glickson (1986) states that an alpha frequency of 10 Hz is optimal for perceiving visual hallucinations. He assumes that it's the change in alpha activity and not the alpha activity itself that is facilitating an altered state of consciousness.
Even if research is not sufficient so far, Michael Hutchison and other scientists report strong tranquilizing effects that lasted up to 3 days. After several sessions it is observed that users can produce a desired brain state with the associated brainwaves easier and deliberately.
Clinical research has been done on the use of auditory and visual stimulation to improve cognitive abilities in learning-disabled children as well as in the treatment of autism and attention deficit hyperactivity disorder (ADHD). However, lacking enough evidence to conclude that these treatments show efficacy, several studies indicate the potential to increase effects on IQ and reading levels in primary students (cite Olmstead, 2005), but also improvements in inattention and impulsiveness in children with ADHD (cite Siever).
Rapidly flashing lights may be dangerous for people with photosensitive epilepsy or other nervous disorders. It is thought that one out of 10,000 adults will experience a seizure while viewing such a device; about twice as many children will have a similar ill effect.