Before the demonstration, discuss
science as a key element in psychology. Ask students to explain what differentiates
"science" from other studies. This, by the way, is quite interesting. Though
students frequently use the word "science" they have rarely considered
what makes science "science" and why, say English, is NOT science. This
makes a good foray into the history of psychology, encouraging a clear
distinction between psychology and other disciplines such as philosophy,
religion, or history.
The day before the demonstration ask a
discrete student to participate in the classroom hoax. During the demonstration,
this student must act surprised, pretending you have read his/her mind.
Inform the class that you can read minds.
Pass out the envelopes and the paper. Ask the students to write a sentence
on the paper, then insert the paper into the envelope. Do not let the students
seal the envelopes. Randomly collect the envelopes using all the drama
you can produce. As you collect the envelopes, make certain to put your
student collaborator's envelope at the bottom of the pile. This must be
the last one you try to read.
Hold the first envelope to your head, like
Johnny Carson did as Karnak the Great. Close your eyes, and recite a sentence
that your student-collaborator might write. The student collaborator then
shouts out, "That's mine!!!! How did you know that?" The student should
act astonished.
As the student claims to have written the
sentence, open the envelope, pretending to check your answer. Silently
read what another student actually wrote. Throw the paper away, hold the
next envelope to your head an recite what you read on the previous paper.
This time another student will, genuinely astonished, say that the sentence
is his/hers. Open the envelope and read the next sentence. The key is to
stay one envelope ahead.
After about four or five envelopes, stop
and help the students establish possible explanations -- (a) You can read
minds, or (b) there is some trick. Recast the word trick to explain there
is an element they are not considering, a variable, that explains your
ability to read minds. Without discussion, have the students brainstorm
variables that might explain how you are doing this.
Select one or two variables from the student
list and control for those. For example, a student claims "You can see
through the envelope!" So, next time hold the envelope under a chair as
you "read" the sentence inside. Slowly eliminate variables, until the students
figure it out. Discuss the idea variables, controlling for variables, and
a systematic method of problem-solving.