Telepathy appears as a story element in many science fiction stories.  In most cases, it is depicted as a naturally-occurring sensory perception based on "physical laws yet to be discovered."  This left me unsatisfied, and I considered how telepathy might be implemented with current or forseeable technology.

In my story, Loyal Puppies (Fantasy & Science Fiction, March 2000), two teenagers communicate "telepathically" via implanted cellphone chips.  As depicted in the story, the chips are plugged into jacks with direct connections to the cranial nerves.  One set of chips is connected to the cochlear nerves that run to the ear.  Another chip is connected to the laryngeal nerve that runs to the vocal cords.

The advantage of connecting to the cranial nerves rather than to the brain itself is that the cranium would not have to be opened.  Each cranial nerve exits the skull through naturally occurring openings.  Connecting to them would only require minor surgery with a local anesthetic, and would be much less invasive to the patient than actually boring a hole in her skull!

In Loyal Puppies, the main characters, Denyssa and Gwen, are able to transmit their "inner speech" to each other.  Their telepathic abilities are restricted to the transmission of sounds.  It might be possible someday to transmit the images that cross the mind's eye, or tactile or olfactory sensations, but these seem more complicated to me, so for the purposes of my story, I restrict the telepathic communication only to the "mind's ear."

The receiving function of auditory telepathy could be implemented with current technology.  Traditional hearing-aids amplify ambient sound.  Sound, of course, is produced by air pressure; the ear is a bio-mechanical system for converting changes in pressure into electrical impulses.  When the bio-mechanical system of the ear is completely dysfunctional, simply turning up the volume won't help.  Cochlear implants pick up ambient sound and transmit it directly to the cochlear nerve.  Instead of picking up ambient sound, the technology could be easily adapted to pick up the frequencies in which wireless cell phone communication is sent.

If it could be done, then why hasn't it?  Because there is no market for such a device.  Without the ability to send messages, being able to receive is useless.

The ability to send thoughts telepathically is not yet feasible, but a solution may not be that far off.  Certainly, it would be possible today to create a device which one could whisper into.  Those whispers could be amplified and transmitted via cellphone transmission.  It would be cheating to call this telepathy, however.  In order to qualify as telepathy, the user must have the ability to think silently about something, and have a facsimile of those thoughts transmitted to someone else.

Such a device might evolve out of the artificial larynx, which provides victims of throat cancer with a replacement for the sounds produced by the vocal cords.  At present, the electrolarynx simply produces a basic tone, which fills the mouth cavity where it is modified by the normal tongue and lip movements that produce speech.  Typically, the tone is turned on and off through the patient pressing a neck-mounted switch.

Researchers at the Massachusetts Eye and Ear Infirmary, according to Technology Review (May/June 2000),  are developing an electrolarynx which could be turned on and off under direct neural control, allowing for hands-free operation.  Another goal is to eliminate the need for a battery by harnessing the body's own electrical potential.  There is a long road ahead before an artificial speech prosthesis can be developed that can actually decode the neural signals, and produced fully formed words, without the use of the mouth cavity.  If one could be developed, could it detect thoughts?

I first came across the notion of "inner speech detection" in Harvard University researcher Stephen Michael Kosslyn's Ghosts in the Mind's Machine (1983).  Kossyln argued for the reality of mental imagery and inner thought, in opposition to Behaviorist notions that such imagery was always the response to external stimuli.  John B. Watson, the founder of Behaviorism, even claimed that inner speech, the stream of consciousness, was produced by tiny movements of the larynx.  According to Watson, the physical movement of the larynx was the cause, and inner speech was the effect.

Watson cited the work of Edmund Jacobson, who first showed that inner thought is accompanied by muscular activity, in the larynx and in many other neuromuscular systems throughout the body.  Jacobson summarized the work of his long and productive career, which he began as a student of William James, in Biology of Emotions (1967).  In pioneering work using  the electromyograph (EMG) to measure nerve impulses in muscles, he demonstrated that imagery is accompanied by slight muscular stimulation.  When one pictures a landscape in the mind's eye, there are small contractions in the eye muscles.  When one imagines oneself running, there is a small increase in muscular tension in the leg muscles.  When one imagines oneself speaking ( i.e. hears one's own inner speech) there is tension in the laryngeal muscles.

Why does this occur?  It seems to me that imagery is used to "warm-up" the muscles, to prime them, so that when a decision is made to run, for instance, it can be done instantly.  Some movements require complex coordination of muscles, and a warm-up period may help with coordination.  The cerebellum is a part of the brain which maintains the coordination of body movements, partly by inhibiting muscular action until the appropriate time.

It therefore occurs to me that, once an artificial prosthesis is developed that can produce fully-formed speech,  it would be possible for it to detect inner speech by simply being sensitive to lower volumes.  When the user is merely thinking, these signals could still be picked up, and transmitted if the user so chose.  The user would want the ability to "mute" their thoughts, so that even in the middle of a telepathy conversation they could have a private moment.  In fact, I believe the mute option would be the default, with transmission only occurring when they user specifically wills it.

In my story, telepathic communication is directed to a specific receiver at a specific telephone number.  The telepathy as ESP commonly depicted, never explains how thoughts can be sent to specific receivers without being picked up by the wrong person.  Who would want their innermost thoughts leaking all over the place, being picked up by anyone with the equivalent of a police scanner?

If telepathy ever does come into being, assuring the privacy of communications is clearly the most important non-technical issue.  From the civil liberties point of view, preventing governments, large corporations, or any unauthorized users from "wiretapping" inner thoughts is surely critical.