There is a theory that EVP can be explained by our own psychic impressions or thoughts. For example, if we ask a question during EVP work, it is possible we have already considered the potential answers. So, the theory is when we receive an EVP reply to a question, that maybe it isn't somebody else, but our own energy impressions from our minds. We are in effect, answering our own questions and thus supplying EVPs in response, subconsciously of course. So based on that theory I have thought of an experiment to try alone, and then with as many people as you can get to particpate.
To do this simple experiment, you will need:
(1) Voice Recorder
(12) Blank cards
On the twelve, blank cards, write one word on each side. Make this an object, or noun, so that it will instill a strong image when seen. So, rather than animals, write down "dog", and rather than furniture, write down "chair." Now you can also (if you wish) write numbers on the back as well.
Start your recorder and with each card you will only say out loud, the number, then read the object word on the card in your head and really concentrate on the word by saying it over and over in your mind. Give yourself 10-20 seconds per card (or longer if you need to concentrate) and keep in mind to only say the number, not the object written down.
You may discover results at first, if not, keep trying, and make sure you concentrate each time. It will help to do this experiment in an environment that is quiet and without any inside or outside noise. Keep doing this experiment and see if you can achieve results, or perhaps learn to harness the energy of your the mind.
I encourage you to try this with other people as well. You don't even have to tell them what they are doing; tell them they are doing a mind bender or mind teaser. Hold up each card to them and say the number out loud and tell them to never say the object out loud on the card, only think it and concentrate on it over and over again. Do it a few times if you like, and again, revisit this person later to see if they're results change.
We know the mind is still a scientific mystery and that energy is abound with all its activities, so if we could somehow tap in and record that energy, then this might be part of the reasoning behind EVPs. It is worth trying in any case to see if results can be found.