Do people have almost same brain-waves (Waves that captured by EEG) while they are thinking the same thing (For example thinking about an Apple)?

To put it another way, are there patterns in measured brain activity that can reveal what someone is thinking about?

  • I've tidied up the language and tried to focus your claim a little. I hope I haven't misrepresented it.
    – matt_black
    Jan 18, 2014 at 13:46
  • Bill was thinking about an Apple IIe, Fred was thinking about the red apple he saw his manager eating on the job, Sue was thinking about Apple corporation's P/E ratio, Ted was thinking about an apple being made into apple sauce. Why would their brainwaves be the same?
    – Paul
    Jan 19, 2014 at 13:41
  • Yeah! That's one of things that concerns me! It's related to the picture that anyone has, from a specific thing in his mind. But I actually mean brainwaves of different people who are thinking to the same picture. This one makes sense! Isn't it!? Jan 19, 2014 at 14:33
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    Note that brain waves are the sum of the activity of thousands of neurons. They are quite a course measure of brain activity. Picking up something so subtle as distinguishing between, say, seeing an apple from seeing a pear (or an elephant for that matter) from an EEG is probably highly unlikely.
    – nico
    Jan 19, 2014 at 22:04
  • I talked to a neurology specialist about this, and he said : People's EEG signals are not the same while they're thinking to the same thing. But the point is, if they are, it would leads something like Hive Mind! Means if somebody who stands near you is angry, he's feeling will also affect you! Jan 30, 2014 at 16:18

1 Answer 1


No. EEGs can be used to monitor the general mental state of a person and to diagnose disease. The kind of resolution that EEGs have, that is very responsive but with a low spatial definition, lets us examine the kind of electrical wave patterns in the brain. For example, alpha waves indicate a person being relaxed (Ref.)

Some experiments have been performed to "read" people thoughts with another tool, fMRI. This is called "thought identification" and it is not at all controversial that it is being performed, as the page I linked shows with good references.

For example IBM patented a machine to retrieve images from scans and visual images have been reconstructed in an experiment.

Even then, fMRI is tricky to use correctly, as shown by recent results and meta-analyses (Scientific American, The Scientist). This doesn't mean that the results are bogus, but that results are way harder to achieve than "reading the brain waves".

  • I though a lot of fMRI results were statistically very dodgy? There are many interesting claims but also many other experts who dispute them.
    – matt_black
    Jan 18, 2014 at 14:25
  • I wonder if @matt is referring to stories like this: blogs.scientificamerican.com/scicurious-brain/2012/09/25/… (I am surprised by some of the claims here, but remain open minded because I haven't yet read the references.)
    – Oddthinking
    Jan 19, 2014 at 14:31
  • @Oddthinking Yes I was, though your reference may prove better than mine as an explanation. I was going to use, inter alia this link from The Scientist.
    – matt_black
    Jan 19, 2014 at 15:49
  • Thanks for your reply. So finally which type of brain waves/signals related to thinking ? (that should be actually related to neurons, I think) Jan 19, 2014 at 19:32
  • @HamedShams there are no waves related to thinking. They are more... states of consciousness. No specific thought can be retrieved with an EEG.
    – Sklivvz
    Jan 19, 2014 at 19:33

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