With sophisticated techniques likes ERP, it is possible to correlate certain EEG activity with certain overt/covert actions.

What I'm wondering is: is there a risk for 2+ overt/covert actions producing identical EEG activity? Meaning:

  • Perhaps when I go to open/close my right hand, I produce certain neural activity (lets just summarize this as A1); where A1 is a specific set of wave signatures
  • Perhaps when I go to open/close my left hand, I produce neural activity A2 (a specific set of wave signatures that is distinctively/mathematically different than A1)
  • Perhaps there are 10,000 other movements I could make that produced their own distinct set of wave signatures (A3 - A10002), etc.
  • But perhaps when I think of sea turtles and pat my stomach at the same time, I produce the same set of waves as A2 (opening and closing my left hand)

My question is: is this a concern/possibility with EEG/ERP? In other words, can multiple overt/covert intents produce identical wave activity (hence, identical EEG readings)?

  • $\begingroup$ Why the downvote? This question is not a dupe, shows some basic research, is on topic, and is an SSCCE. $\endgroup$
    – smeeb
    Mar 18, 2016 at 6:50
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    $\begingroup$ EEG/ERP are methods applied with a goal in mind. Your question asks for a concern, without defining the purpose to measure EEG/ERPs in the first place. That makes the question open for interpretation, vaguely defined and hence making the answer pob. That may explain the downvote, but I can't really speak for others $\endgroup$
    – AliceD
    Mar 18, 2016 at 8:01
  • $\begingroup$ Thanks @Christiaan (+1) - but I (respectfully!) disagree, I don't think this is vague. All I'm asking is: is it possible for two distinct thoughts to produce the same electrical signature on an EEG? $\endgroup$
    – smeeb
    Mar 18, 2016 at 8:04
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    $\begingroup$ Also, don't worry too much about a downvote or two. It's all in the game. Upvotes give you more rep than downvotes take away anyway. $\endgroup$
    – AliceD
    Mar 18, 2016 at 8:20
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    $\begingroup$ I know! I've been on various StackExchange sites for many years now and know that - typically - one lone downvote/closevote can often trigger a "Mob Lemming Effect" and cascades into multiple users mindlessly repeating the down/closevote. And I've found that defending a question with my above boilerplate response usually helps prevent this Mob Lemming Effect from continuing any further :-) $\endgroup$
    – smeeb
    Mar 18, 2016 at 12:40

1 Answer 1


To curtly answer your question: given the sheer amount of different thoughts possible (billions I guess) and the limited spatial resolution of the standard EEG as well as the restricted number of characteristic parameters to describe EEGs (frequency, amplitude, latency) it is safe to say EEG is not suitable to characterize all of the brains processes. In fact, no state-of-the-art technique can do so, as far as I can see.

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    $\begingroup$ Thanks (as always) @Christiaan (+1) - however I feel like you might not be understanding my question. Let's take a concrete example: is it possible that blinking my left eye might show up (analytically-speaking) to have an identical "wave signature" as, say, wiggling my big toe? By "identical wave signature", what I really mean is "identical results/outputs on an EEG reading." Does that make more sense? Thanks again! $\endgroup$
    – smeeb
    Mar 18, 2016 at 11:32
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    $\begingroup$ What christiaans Answer means is: Yes it is possible that different intents show up with the same EEG signature. This is due to the fact that the resolution of an EEG is not large enough to distinguish all possible intents simply because the parameter space resolved by an EEG is much smaller than the space of all possible intents produced by the brain. $\endgroup$
    – Thawn
    Mar 23, 2016 at 10:10
  • $\begingroup$ Thanks for the clarification @Thawn (+1) - unfortunately since you are only leaving a comment I can't qualify you for the bounty, but your comment is immensely appreciated! $\endgroup$
    – smeeb
    Mar 25, 2016 at 15:03

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