How did he read my mind?

How did my friends do this mind read magic trick?

• Here is how the trick works. 1. The mind reader leaves the room 2. I choose an object, say "tree" and I tell it to the mind reader's "assistant" 3. The mind reader comes back in, and tells me to name categories similar to the object. 4. I say nature, industrial area, ocean, and space 4. The mind reader is able to guess that my object lies within the nature category 5. The mind reader then says I was thinking about a tree. My question is, how do they do that trick? It doesn't matter what object I choose he will always get ir right. How does his assistant give him the answer without speaking it or writing it I think? Also, I'm pretty sure they didn't have microphones because I very quitely whisper it to his ear, and I can also write down what I'm thinking, I don't have to say it to the assistant. Thank you in advance for answers.

• Answer:

  Why does a mind reader need an assistant if they are mind readers?? Can your simple brain realize the answer? Why else, but to find out the answer and signal the mind reader because he is a phony mind reader! Next time tell the mind reader he doesn't have to leave the room - you will leave the room and chose the object in private and write it down on a piece of paper. See how successful his reading will be then!