Introduction
Hemi-Sync is a patented(1) auditory-guidance system developed by Robert A. Monroe which provides access to beneficial states of consciousness. The trademarked term Hemi-Sync signifies a process, a procedure in which individuals willfully participate by listening to a combination of multiplexed audio binaural beats that are mixed with music, pink sound(2), and/or surf and by focusing attentional processes. In most cases the Hemi-Sync process also includes breathing exercises, guided relaxation, affirmation, and visualization. The binaural-beat element of the Hemi-Sync process appears to be associated with an electroencephalographic (EEG) frequency-following response in the brain(3). Many studies have demonstrated the presence of a frequency-following response to auditory stimuli, recorded at the vertex of the human brain (top of the head). This EEG activity was termed "frequency-following response" because its period corresponds to the fundamental frequency of the stimulus (Smith, Marsh, & Brown, 1975). Binaural-beat stimulation, coupled with the effects of the other procedures within the Hemi-Sync process, appears to encourage access to altered states of consciousness. The effectiveness of Hemi-Sync in engendering state changes is supported by the consistent reports of thousands of Hemi-Sync users, as well as the documentation of physiological changes associated with Hemi-Sync use.
The reported uses of Hemi-Sync range from relaxation, meditation, stress reduction, pain management, improved sleep quality, health care (Carter, 1993), and enriched learning environments to creativity, enhanced intuition, remote viewing(4) (McMoneagle, 1993), telepathy(5), and out-of-body experience(6). An understanding of the Hemi-Sync technology involves the well-known autonomic effects of controlled breathing and progressive relaxation and the psychology of affirmations and visualizations. This understanding also includes the physics of resonant entrainment, brain waves and their relationship to the behavioral psychology of consciousness, and the physiology of the brain. For the purposes of this paper, discussion is limited to the latter portions of this understanding as the former have been described elsewhere.
The Physics of Resonant Entrainment
Resonant entrainment of oscillating systems is a well-understood principle within the physical sciences. If a tuning fork designed to produce a frequency of 440 Hz is struck (causing it to oscillate) and then brought into the vicinity of another 440 Hz tuning fork, the second tuning fork will begin to oscillate. The first tuning fork is said to have entrained the second or caused it to resonate. The physics of entrainment apply to biosystems as well. Of interest here are the electromagnetic brain waves. The electrochemical activity of the brain results in the production of electromagnetic wave forms which can be objectively measured with sensitive equipment. Brain waves change frequencies based on neural activity within the brain. Because neural activity is electrochemical, brain function can be modified through the introduction of specific chemicals (drugs), by altering the brain's electromagnetic environment through induction(7), or through resonant entrainment techniques. Caffeine, nicotine, and alcohol are drugs. Heterodyning radio and microwave frequencies all around us and the binaural beats of the Hemi-Sync process are entrainment environments.
Hemi-Sync's Binaural Beats and The Physiology of the Brain
Binaural beats were discovered in 1839 by a German experimenter, H. W. Dove. The human ability to "hear" binaural beats appears to be the result of evolutionary adaptation. Many evolved species can detect binaural beats because of their brain structure. The frequencies at which binaural beats can be detected change depending upon the size of the species' cranium. In the human, binaural beats can be detected when carrier waves(8) are below approximately 1000 Hz (Oster, 1973). Below 1000 Hz the wave length of the signal is longer than the diameter of the human skull. Thus, signals below 1000 Hz curve around the skull by diffraction. The same effect can be observed with radio wave propagation. Lower-frequency (longer wave length) radio waves (such as AM radio) travel around the earth over and in between mountains and structures. Higher-frequency (shorter wave length) radio waves (such as FM radio, TV, and microwaves) travel in a straight line and can't curve around the earth. Mountains and structures block these high-frequency signals. Because frequencies below 1000 Hz curve around the skull, incoming signals below 1000 Hz are heard by both ears. But due to the distance between the ears, the brain "hears" the inputs from the ears as out of phase with each other. As the sound wave passes around the skull, each ear gets a different portion of the wave. It is this waveform phase difference that allows for accurate location of sounds below 1000 Hz(9). Audio direction finding at higher frequencies is less accurate than it is for frequencies below 1000 Hz. At 8000 Hz the pinna (external ear) becomes effective as an aid to localization. Virtually all animal sounds are below 1000 Hz. It is easy to imagine why animals developed the ability to accurately detect the location of each others' sounds(10). The relevant issue here, however, is that it is this innate ability of the brain to detect a waveform phase difference that enables it to perceive binaural beats.
When signals of two different frequencies are presented, one to each ear, the brain detects phase differences between these signals. "Under natural circumstances a detected phase difference would provide directional information. The brain processes this anomalous information differently when these phase differences are heard with stereo headphones or speakers. A perceptual integration of the two signals takes place, producing the sensation of a third "beat" frequency. The difference between the signals waxes and wanes as the two different input frequencies mesh in and out of phase. As a result of these constantly increasing and decreasing differences, an amplitude-modulated standing wave -the binaural beat- is heard. The binaural beat is perceived as a fluctuating rhythm at the frequency of the difference between the two auditory inputs. Evidence suggests that the binaural beats are generated in the brainstem's superior olivary nucleus, the first site of contralateral integration in the auditory system (Oster, 1973). Studies also suggest that the frequency-following response originates from the inferior colliculus (Smith, Marsh, & Brown, 1975)" (Owens & Atwater, 1995). This activity is conducted to the cortex where it can be recorded by scalp electrodes.
Binaural beats can easily be heard at the low frequencies (< 30 Hz) that are characteristic of the EEG spectrum (Oster, 1973). This perceptual phenomenon of binaural beating and the objective measurement of the frequency-following response (Hink, Kodera, Yamada, Kaga, & Suzuki, 1980) suggest conditions which facilitate entrainment of brain waves and states of consciousness. There have been numerous anecdotal reports and a growing number of research efforts reporting changes in consciousness associated with binaural-beats. "The subjective effect of listening to binaural beats may be relaxing or stimulating, depending on the frequency of the binaural-beat stimulation" (Owens & Atwater, 1995). Binaural beats in the delta (1 to 4 Hz) and theta (4 to 8 Hz) ranges have been associated with reports of relaxed, meditative, and creative states (Hiew, 1995), and used as an aid to falling asleep. Binaural beats in the alpha frequencies (8 to 12 Hz) have increased alpha brain waves (Foster, 1990) and binaural beats in the beta frequencies (typically 16 to 24 Hz) have been associated with reports of increased concentration or alertness (Monroe, 1985) and improved memory (Kennerly, 1994).
Passively listening to binaural beats may not spontaneously propel you into an altered state of consciousness. Remember, the Hemi-Sync process includes a number of procedures; binaural beats are only one element. We all maintain a psychophysiological momentum, a homeostasis which resists the influence of the binaural beats. These homeostatic environments are generally controlled by life situations as well as by acts of will, both conscious and subconscious, and must be overcome to experience shifts in consciousness. One's subjective experience in response to binaural-beat stimulation may also be influenced by a number of mediating factors. For example, the willingness and ability of the listener to relax and focus attention may contribute to binaural-beat effectiveness in inducing state changes. "Ultradian rhythms in the nervous system are characterized by periodic changes in arousal and states of consciousness (Rossi, 1986; Shannahoff-Khalsa, 1991; Webb & Dube, 1981). These naturally occurring shifts may underlie the anecdotal reports of fluctuations in the effectiveness of binaural beats. External factors are also thought to play roles in mediating the effects of binaural beats" (Owens & Atwater, 1995). The perception of a binaural beat is, for example, said to be heightened by the addition of white noise to the carrier signal (Oster, 1973), so white noise is often used as background. "Music, relaxation exercises, guided imagery, and verbal suggestion have all been used to enhance the state-changing effects of the binaural beat" (Owens & Atwater, 1995). Other practices such as humming, toning, breathing exercises, autogenic training, and/or biofeedback can also be used to interrupt the homeostasis of resistant subjects (Tart, 1975).
Brain Waves and Consciousness
Controversies concerning the brain, mind, and consciousness have existed since the early Greek philosophers argued about the nature of the mind-body relationship, and none of these disputes has been resolved. Modern neurologists have located the mind in the brain and have said that consciousness is the result of electrochemical neurological activity. There are, however, growing observations to the contrary. There is no neurophysiological research which conclusively shows that the higher levels of mind (intuition, insight, creativity, imagination, understanding, thought, reasoning, intent, decision, knowing, will, spirit, or soul) are located in brain tissue (Hunt, 1995). A resolution to the controversies surrounding the higher mind and consciousness and the mind-body problem in general may need to involve an epistemological shift to include extra-rational ways of knowing (de Quincey, 1994) and cannot be comprehended by neurochemical brain studies alone. We are in the midst of a revolution focusing on the study of consciousness (Owens, 1995). Penfield, an eminent contemporary neurophysiologist, found that the human mind continued to work in spite of the brain's reduced activity under anesthesia. Brain waves were nearly absent while the mind was just as active as in the waking state. The only difference was in the content of the conscious experience. Following Penfield's work, other researchers have reported awareness in comatose patients (Hunt, 1995) and there is a growing body of evidence which suggests that reduced cortical arousal while maintaining conscious awareness is possible (Fischer, 1971; West 1980; Delmonte, 1984; Goleman 1988; Jevning, Wallace, & Beidenbach, 1992; Wallace, 1986; Mavromatis, 1991). These states are variously referred to as medi- tative, trance, altered, hypnagogic, hypnotic, and twilight-learning states (Budzynski, 1986). Broadly defined, the various forms of altered states rest on the maintenance of conscious awareness in a physiologically reduced state of arousal marked by parasympathetic dominance (Mavromatis, 1991). Recent physiological studies of highly hypnotizable subjects and adept meditators indicate that maintaining awareness with reduced cortical arousal is indeed possible in selected individuals as a natural ability or as an acquired skill (Sabourin, Cutcomb, Crawford, & Pribram, 1993). More and more scientists are expressing doubts about the neurologists' brain-mind model because it fails to answer so many questions about our ordinary experiences, as well as evading our mystical and spiritual ones. The scientific evidence supporting the phenomenon of remote viewing alone is sufficient to show that mind-consciousness is not a local phenomenon (McMoneagle, 1993).
If mind-consciousness is not the brain, why then does science relate states of consciousness and mental functioning to brain-wave frequencies? And why does the Hemi-Sync process include a binaural-beat technology which has the potential to alter brain waves? The first question can be answered in terms of instrumentation. There is no objective way to measure mind or consciousness with an instrument. Mind-consciousness appears to be a field phenomenon which interfaces with the body and the neurological structures of the brain (Hunt, 1995). One cannot measure this field directly with current instrumentation. On the other hand, the electrical potentials of brain waves can be measured and easily quantified. Contemporary science likes things that can be measured and quantified. The problem here lies in oversimplification of the observations. EEG patterns measured on the cortex are the result of electroneurological activity of the brain. But the brain's electroneurological activity is not mind-consciousness. EEG measurements then are only an indirect means of assessing the mind-consciousness interface with the neurological structures of the brain. As crude as this may seem, the EEG has been a reliable way for researchers to estimate states of consciousness based on the relative proportions of EEG frequencies. Stated another way, certain EEG patterns have been historically associated with specific states of consciousness. It is reasonable to assume, given the current EEG literature, that if a specific EEG pattern emerges it is probably accompanied by a particular state of consciousness. The second question raised in the above paragraph requires a more complex explanation. The Hemi-Sync process includes the powerful binaural-beat technology because altering the electrochemical environment of the brain allows mind-consciousness to have different experiences. When the brain is entrained to lower frequencies and awareness is maintained, a unique state of consciousness emerges. Practitioners of the Hemi-Sync process call this state of hypnagogia "mind awake/body asleep." Slightly higher-frequency entrainment can lead to hyper suggestive states of consciousness. Still higher-frequency EEG states are associated with alert and focused mental activity needed for the optimal performance of many tasks. Perceived reality changes depending on the state of consciousness of the perceiver (Tart, 1975). Some states of consciousness provide limited views of reality, while others provide an expanded awareness of reality. For the most part, states of consciousness change in response to the ever-changing internal environment and surrounding stimulation. For example, states of consciousness are subject to influences like drugs and circadian and ultradian rhythms (Rossi, 1986; Shannahoff-Khalsa, 1991; Webb & Dube, 1981). Specific states of consciousness can also be learned as adaptive behaviors to demanding circumstances (Green and Green, 1986). The Hemi-Sync process offers access to a wide variety of altered-state experiences.
Beyond the Basics
The term Hemi-Sync was chosen because many of the states of consciousness available through this technology have been identified as presenting unique hemispherically-synchronized brain-wave frequencies. Although synchronized brain waves have long been associated with meditative and hypnagogic states, the Hemi-Sync process may be unique in its ability to induce and improve such states of consciousness. The reason for this is physiological. Each ear is "hardwired" (so to speak) to both hemispheres of the brain (Rosenzweig, 1961). Each hemisphere has its own olivary nucleus (sound-processing center) which receives signals from each ear. In keeping with this physiological structure, when a binaural beat is perceived there are actually two standing waves of equal amplitude and frequency present, one in each hemisphere. So, there are two separate standing waves entraining portions of each hemisphere to the same frequency. The unique binaural beats of the Hemi-Sync process appear to contribute to the hemispheric synchronization evidenced in meditative and hypnagogic states of consciousness. Hemi-Sync's binaural beats can also enhance brain function by enabling the user to mediate cross-collosal connectivity at designated brain-wave frequencies.
The two cerebral hemispheres of the brain are like two separate information processing modules. Both are complex cognitive systems; both process information independently and in parallel; and their interaction is neither arbitrary nor continuous (Zaidel, 1985). Because of this, states of consciousness (mind-consciousness interfacing with the brain) can be defined not only in terms of brain-wave frequency ratios, but also in terms of hemispheric specialization and/or interaction. Some desired states of consciousness may require facile inter-hemispheric integration, while others may call for a unique hemispheric processing style. An individual's cognitive repertoire and, therefore, his ability to perceive reality and deal with the everyday world, is subject to his ability to experience various states of consciousness. The Hemi-Sync process provides the tools for individuals to expand their ability to experience a wide range of mind-consciousness states.
Each state of consciousness is not represented by one simple brain wave. Each state of consciousness involves a milieu of inner-mixing wave forms. The reason for this lies in the structure of the brain itself. Not only is the brain divided horizontally into hemispheres, it is also divided vertically into the cerebellum, the thalamus, the limbic system, and the cerebral cortex. The cerebral cortex is further divided into such functional areas as the frontal lobes, the parietal lobes, the temporal lobes, and the occipital lobes. There are, of course, many other subdivisions of the brain which have not been mentioned. The critical point is that for each discrete state of consciousness, mind-consciousness interfaces with each area of the brain and each area resonates at a specific brain-wave frequency unique to that interface because it performs a localized function (Luria, 1970).
The Monroe Institute has been studying altered states of consciousness and developing Hemi-Sync binaural beats for more than thirty years. The process of developing effective stimuli relied initially on the feedback of those experiencing altered states associated with listening to binaural beats, and more recently with the aid of EEG technology. Originally, Robert Monroe tested many subjects under laboratory conditions for their responses to binaural-beat stimuli. Records were kept as to the effect each binaural-beat frequency had on these subjects. Then binaural beats were mixed and records were again kept on the subjects' responses. After months (in some cases, years), test results began to show population-wide similar responses to specific mixes of binaural beats. Certain combinations of binaural beats were reported more effective than other combinations, and more effective than binaural beats of single frequencies.
Given the complexity of brain function and the likelihood that the mixture of EEG frequencies results from different generators localized in different regions of the brain, it was theorized that to entrain a particular state of consciousness one must identify these complex wave forms and mimic them through the use of a number of multiplexed carrier signals generating heterodyned binaural beats. It may be the complexity of the stimuli that makes the binaural beats of the Hemi-Sync process so effective. Theoretically, the heterodyned binaural beats within these unique mixes entrain separate areas of the brain to different frequencies, reliably producing altered states with similar characteristics.
It is tempting to speculate about a neurophysiological model underlying the state of consciousness labeled Focus 10 (mind awake/body asleep). In Focus 10 a greater proportion of lower frequency brain waves (theta and delta) have been recorded in the EEG. The "body asleep" part of Focus 10 may be tied to the increase in delta waves associated with hyperpolarization of thalamocortical cells (Steriade, McCormick, & Sejnowski, 1993). The "mind awake" part of Focus 10 may be achieved by entraining a portion of the hippocampus to a theta frequency. The subject's exposure to these individual binaural beats is timed, introducing the delta signals first and later mixing in theta signals. This allows for a dissolution of the psychophysiological homeostasis and for changes in consciousness. This Focus 10 Hemi-Sync binaural-beat signal seems to have a soothing entrainment effect on the limbic system (the brain's emotional center) as evidenced by the many participants who report that Focus 10 is a very pleasant experience. Participants are said to have achieved Focus 10 mind-consciousness when a new condition of hypnagogic homeostasis is established and they become oblivious to the location of body extremities (hands, feet, etc.), still without losing consciousness (falling asleep). During this state, participants are usually focused on internal processes (imagery, etc.). Participants return easily to full physical-waking consciousness when the Focus 10 binaural-beat signal is turned off.
Summary
The Hemi-Sync auditory-guidance process provides access to many beneficial mind-consciousness states. This process is a unique combination of well-understood inductive techniques with the addition of a refined binaural-beat technology which appears to have a brain-wave entrainment effect. The Hemi-Sync process is safe and effective and has a wide variety of applications which include, but are not limited to: relaxation, meditation, intuition development, enriched learning, improved sleep, wellness, and the exploration of expanded mind-consciousness states(11).
Footnotes
References
About the Author
F. Holmes (Skip) Atwater works in the lab at The Monroe Institute. He is an experienced mind-consciousness voyager and has contributed to the evolution of the Hemi-Sync process and the Institute since 1977. In September 1988, he initiated the now ongoing psychophysiological research at the Institute. Skip also monitors personalized mind-consciousness excursion sessions (voyages into the realms of consciousness using Hemi-Sync technology) conducted in the lab's isolation booth. Skip, a retired military officer, has been a college instructor, author, scientific investigator, and human behavioral engineer specializing in the design and application of techniques for cultivating propitious states of consciousness for more than two decades.
Hemi-Sync is a registered trademark of The Monroe Institute
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