Mind machine

 ( Meditation ) 

The first scientific observations were made by William Charles Wells in the 1790s who described different effects of binocular vision. His results were later transferred to be applied in binaural beats. Visual experiments with flickering lights were conducted in the 1940s by William Grey Walter who used stroboscopic light flashes to measure their effects on brain activity, assessed with EEG. He reported effect not just on visual areas but on the whole cortex.

The development of alpha EEG feedback (see neurofeedback) is an important starting point for biofeedback and its explicit use for entering altered states of consciousness. Enterprises started to produce different types of mind machines and some scientists followed the line of research to explore if and how these devices elicit effects on brain processes.

In the late 1980s and early 1990s Farley initiated an investigation concerning medical claims made by some manufacturers and sellers. The FDA concluded that Light and Sound Machines were not medical devices and did not warrant regulation. Sellers and manufacturers were given guidelines for how they could advertise these devices, and were required to include a disclaimer and cautionary document with each machine. Nowadays, mind machines are rediscovered by some teenage cultures as so called "digital drugs", a legal way to enter altered states of consciousness.