• Earth, in the future, near 2060 or 2100
  • Technology: a bit more advanced than ours

Armies and police forces are already using systems for crowd control. Some devices can generate discomfort or pain using sound frequencies or electromagnetic radiation (microwaves).

Most of these devices are made to reduce violent behaviours but, could they have a wider range of uses? Could they also trigger other emotions and ultimately, could they be used as a mean to control the populations?

Speculations: I imagine that a state could deploy antennas across the land to send the frequencies. Maybe they could target specific area instead of a wide area. Maybe they could have these devices in all buildings and could monitor the people to influence their behaviour in real time.

Would that be possible with the right technology?

  • 4
    $\begingroup$ If you weren't wearing a tin foil hat when you typed it, then the government probably made you post it, in order to track down the people who might be on to them. But I've said too much... $\endgroup$ Commented Nov 2, 2014 at 0:59
  • $\begingroup$ More seriously, you mention monitoring in addition to controlling... Between cell phone tracking and video surveillance cameras, there are already some options here. $\endgroup$ Commented Nov 2, 2014 at 1:14
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    $\begingroup$ The NSA is watching us... $\endgroup$
    – Vincent
    Commented Nov 2, 2014 at 2:23
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    $\begingroup$ This is already happening. Some train stations play classical music to prevent people from committing violent crimes. Shops use upbeat music to get people in a mood to consume more. $\endgroup$
    – Philipp
    Commented Nov 3, 2014 at 0:35
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    $\begingroup$ Using frequencies of what? $\endgroup$ Commented Nov 11, 2014 at 16:12

3 Answers 3


Brain Stimulation

For brain research and treatment, there are many forms of electrical brain stimulation (EBS) including transcranial magnetic stimulation, and direct current stimulation. According to Wikipedia:

A comprehensive review of EBS research compiled a list of many different acute impacts of stimulation depending on the brain region targeted. Following are some examples of the effects documented:

  • Sensory: Feelings of body tingling, swaying, movement, suffocation, burning, shock, warmth, paresthesia, feeling of falling, oscillopsia, dysesthesia, levitation, sounds, phosphenes, hallucinations, micropsia, diplopia, etc.
  • Motor: Eye movements, locomotion, speech arrest, automatisms, laughter, palilalia, chewing, urge to move, crying without feeling sad, etc.
  • Autonomic: Blushing, mydriasis, change in blood pressure and breathing, apnea, nausea, tachycardia, sweating, etc.
  • Emotional: Anxiety, mirth, feeling of unreality, fear, happiness, anger, sadness, transient acute depression, hypomania, etc.
  • Cognitive: Acalculia, paraphasia, anomic aphasia, recalling memories, "going into a trance", "out of this world", conduction aphasia, hemispatial neglect, alexia, déjà vu, reliving past experiences, agraphia, apraxia, etc.

EBS in face-sensitive regions of the fusiform gyrus caused a patient to report that the faces of the people in the room with him had "metamorphosed" and became distorted: "Your nose got saggy, went to the left. [...] Only your face changed, everything else was the same."

Note that electrical brain stimulation relies on the patient wearing some type of device (electrodes, coils, a helmet, etc...) and then targeting very specific areas of the brain, sometimes through trial and error. I find it difficult to believe that any type of ranged transmitter device would have either the strength or the accuracy to consistently and accurately produce a specific effect.

Sensory Stimulation

In addition to directly stimulating the brain through electromagnetic means, there is also a more straightforward means of getting "frequencies" into the brain. The eyes detect light frequencies (within the visible range) and the ears detect auditory frequencies (in the audible range). This suggests that messages can be implanted via audio-visual means, which, of course, is the case. In fact, it is far more likely that these means would be used, as they provide a far richer palette of options. Indeed, advertisers, film-makers, and politicians already use much of this. I'm going to break this up into a couple of categories.

  • Linguistic: Control people's actions through words, either spoken or written. Includes rhetorical devices, used by politicians, and pretty much anyone that says (or writes) anything. Imagine giant billboards telling you to be a compliant citizen, or public speakers broadcasting pro-government messages. Could also be done through control of nes stations, social media, websites, educational system, rewriting history, controlling the "narrative", creating new derogatory words for one's opponents, etc...

  • Symbolic: Control people's actions more subtly through non-linguistic cues, such as colors, shapes, sound palettes, etc... It may sound silly, but how many little boys in a toy store would dare to go down the "pink aisle"? Advertisers realize that we never grow out of this, and package similar products separately for men and women, allowing them to perform "gendered pricing". This would also include playing soothing music at train stops, which one of the commenter suggested. Or composing the soundtrack, and adjusting the composition and color balance of films. There's a lot audio-visual meaning that can be conveyed without language. Even gestures and facial expressions could fall into this category.

  • Subliminal Effects: This can be done either linguistically or symbolically, but it involves sending messages that are below the threshold of conscious detection, so that the target is unaware of them. This could also include more traditional hypnotic suggestions.

  • Physiological Effects: This could include things like bright flashing lights, or loud noises, being used to daze and confuse an individual (like a flash bang grenade). In some cases, this may also cause seizures.

  • $\begingroup$ Well, a sufficiently dystopian government could find opportunities to accurately map the brain of every citizen. Have your surveillance cameras identify the citizen through a biometric database, access his brain scan, use image recognition to analyze the current position and rotation of his skull, and then you just have to focus the beam accurately enough, which is just an engineering problem. $\endgroup$
    – Philipp
    Commented Nov 3, 2014 at 0:23
  • $\begingroup$ It would probably be easier to implant electrodes directly in the skull, though that involves a whole different set of engineering problems. $\endgroup$ Commented Nov 3, 2014 at 2:39
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    $\begingroup$ I want to add this: google.com/patents/US6506148 "Nervous system manipulation by electromagnetic fields from monitors." Fortunately we mostly have flatscreens these days. And reality TV puts me on edge anyway. $\endgroup$ Commented Nov 14, 2015 at 5:18

"Frequencies" is a bad way of looking at this. Both sound and EMR involve some sort of oscillation which we can measure the frequency of. They have about as much relationship to one another as the wheel base of a car and the orbital radius of the Earth.

The way crowd control devices like that work is by imparting energy to the senses (the skin, eye, ear) in a way that produces an intense sensation, swamping other sensations and causing discomfort, not by directly affecting the brain to produce an emotion. So no, you can't induce arbitrary emotions through the use of radiation at some particular frequency.

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    $\begingroup$ This doesn't really answer the question -- it's really more of a comment. $\endgroup$
    – Shokhet
    Commented Nov 11, 2014 at 22:22

It really depends on how fine a control you are referring to. As you pointed out there are frequencies they can use for crowd control. There are frequencies below human hearing with longer exposure, (even just the length of a song) can cause many different negative emotions including fear. So yes, I think there could be a bit of control with frequencies especially negative emotions, however, I don't think it would reach to being able to control your individual thoughts, at least not en mass.

  • $\begingroup$ Can't control populations even with conditioning ?: en.wikipedia.org/wiki/Classical_conditioning $\endgroup$
    – Vincent
    Commented Nov 2, 2014 at 15:44
  • $\begingroup$ Really that is controlling responses, not thoughts. $\endgroup$
    – bowlturner
    Commented Nov 3, 2014 at 13:31
  • $\begingroup$ yes but it's the same results in the end $\endgroup$
    – Vincent
    Commented Nov 3, 2014 at 15:31
  • $\begingroup$ @Vincent Not really. You can always override learned responses when you can think, granted the vast majority of people don't think but that is something else. Controlling thoughts prevents you from thinking or acting any other way. $\endgroup$
    – bowlturner
    Commented Nov 3, 2014 at 15:39
  • $\begingroup$ @bowlturner That assumes that you notice there's something to think about. It's well established in psychology that people will reconsider (or even react against) manipulations that they know are happening. But if they don't know that something external is acting on them, they're likely to take their emotions and feelings as a "gut sense" and treat it as reliable -- even coming up with intellectual justifications for it after the fact. $\endgroup$
    – octern
    Commented Nov 3, 2014 at 16:55

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