In the future, we will be able to read each other's minds. It will be like making and receiving a phone call. At first, this technology will be very simple and only allow a limited vocabulary, and it requires no implants or surgery, just some electrodes placed on the head, perhaps in a hood or even a baseball cap, connected to a mobile phone. How will this come to be? Let's see.

An important introduction is to look at what is old, and already possible. People who are disabled and highly immobile have a few technological devices available to control computers in order for them to communicate. For example, measuring a persons eye movement or measuring the activity in nerve endings across a limb. The data is passed to a computer, so that the user can tell the computer what to do.

But neither of these are as nifty as the electroencephalnon graphs that doctors use. These are clunky, awkward headsets that are worn whilst neurologists examine brain wave activity. We can only 'see' general areas of excitement in the brain, and it is impossible to follow trains of thought, ideas, language or complex thoughts. We can only see, in general, what types of things are going on. We can tell if a person is asleep, thinking hard, or using various generic systems in the brain. This is because we can read neurons en masse.

But, using a much simpler technique with just a few electrodes, we will be able to develop technology that results, practically speaking, in telepathy.

“People have already learnt to control computers using their brain waves, read by electrodes on the scalp, or implanted electrodes into which neurones were encouraged to grow.” --New Scientist (1999)

Stage One - What Is Already Possible

A computer reads a particular part of the brain, and responds with either a "positive" or "negative". The person is shown a ball on a screen which he must move to the top of the screen. He learns how to communicate "positive" to the electrode to move it up, and "negative" to move it down. He learns to communicate with the computer to control the ball. They change the software so that he can select letters from the alphabet in order to write letters. The patient (this is a real experiment) writes a letter thanking the scientists and such for giving him an opportunity to "talk".

But such simplistic communication is no good, unless people are willing to send message to each other's computers painfully slowly. A company called Emotiv has produced an prototype EEG that has only 18 electrodes (as opposed to as many as 120 in medical EEGs), that requires no gel:

“Emotiv claims that its system can detect brain signals associated with facial expressions such as smiles and winks, different emotional states such as excitement and calmness, and even conscious thoughts such as the desire to move a particular object. [...] It seems to work well enough to make a virtual character in a game mimic a player's own facial expression, as well as permitting that player to move things around just by thinking about it.” -- The Economist, 2007 Mar 17, p112

Stage Two - Mobile Phones

At the moment, it seems we will surely develop thought-activated computer systems. Detectors that examine the Human eye to see where it is looking can easily be combined with small EEGs to allow control of games like first-person shooters where the computer wants to know which way you want to turn, and what you want to shoot at.

But instead of games, why not translate the activity into messages in a device like a mobile phone? The mobile could then send these digitized messages to another mobile, which could speak them, using a synthesizer, to the recipient? And, if we can ever reverse the system so that we can transmit magnetic fields through the electrodes and understand them with our minds? Such small electrodes cannot transmit more than a very small distance, so we would use mobile devices to do the transmitting for us, potentially even over existing mobile phone networks.

This method may even be pretty cheap to produce; especially if much of the code is written by the games industry. The only thing to retard progress will be the speed at which we can train our brains to output signals that are rapid. Medical experiments have not, so far, allowed anything but quite a slow rate of communication.

Stage Three - Radio Caps

If we can learn to communicate to an electrode in our heads, to a computer, which decodes our signals, translates them and sends them, and another person receives them and decodes them, something more amazing could happen. If two people learn to communicate with the same software, we could possibly remove the software and have two sets of EEG/Receivers simply broadcasting to each other, with no digitisation of the message. This would mean that two people could simply learn to communicate with each other (after having mastered the trick with a more simple computer).

All this technology could be hidden inside a baseball cap (although the method by which our brain reads the magenetic fields from the receiver in the cap may always require a strong magnetic field, and I'm not sure how small we can make these... without them, we'd still need a mobile device to speak the messages to us).

In the future, groups of people could sit in a room thinking to each other. We could never transmit our full thoughts, but only thoughts that we have learned to sent via the electrodes. We simply cannot send our thoughts en masse for the same reasons we cannot read them with a computer - everyone's brain layot is unique and the massive quantity of electrodes required would be completely impractical and rarely accurate.

Different groups of friends, cultures and races would all end up developing different languages over the telepathy net, and all communication could of course be stopped at any time by simply taking the cap off, as the magnetic fields from our brain activity only travel a tiny distance from our heads so that once the cap is removed, the electrode cannot read anything.

So there it is, gadgetry can lead to a form of aided telepathy that dispenses with the need to use the hands.

Natural Telepathy

In my original text (1999), I thought that the next development would be that one human brain would be able to react and communicate via magnetic fields with nearby people who have undergone similar training/learning. I wrote:

“This is the hardest part of the theory to imagine, the stage where people are emitting pulses in the same standard way, much like controlling an extra limb. People have in the process learnt to pickup the standard signals from each other. Creatures' brains are susceptible to electromagnetic fields, such as the way birds use the magnetic fields of the Earth to navigate. [...] The next step, one person being able to understand and pick up the signals from another's neurones is possible but I do not know enough, no-one can, to decide whether it is plausible or not.” --"The Future of Telepathy" (1999) by Vexen Crabtree (recanted)

I was wrong, we certainly know enough to state that this is impossible. Even if all the neurones in the brain fired at the same time, the magnetic influence would still travel only a fraction of a millimeter from the head. The general firings of single neurones are far too minute to be detectable - the best readings with on-the-scalp electrodes still require patients to sit in a room specially sealed from the Earth's level of natural magnetic noise. If we tried to 'listen' to the magnetic information around us from brains, we would always be completely overwhelmed by the random noise of the Earth. It is so loud, it would be impossible to hear anything else. It is not an issue of sensitivity training or skill, but of physics.

Because of this, only general activation of brain circuitry can be detected, and we would need detectors on the scalp (in a hood, as I've been saying) combined with a mobile transmitter, and a receiver to blast our brains with the magnetic fields relevent to the messages that others wish to send us.

With surgery, however, it would become much more effective and accurate, and sensors can be placed much closer to neurones, and even interface directly with them as is the case with the best prosthetics.

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