This activity page will offer:
Insight into echolocation
activity in reflected sound waves
in calculating distance based upon detection of reflected sound
In this activity, you'll explore another aspect of brain trickery.
This time the brain will get fooled into thinking that an image
of a body part is actually detecting "touch" and sending signals
to the brain. As you'll see, it is a bizarre illusion that thoroughly
confuses your brain, resulting in the construction of an erroneous
(For the set-up)
- Work with a partner. Chose one person to be the subject and
one person to be the tester
- Print this image of a hand. The printout should display a near
life-size image of the body part.
NOTE: If you have access to a digital camera, ask your teacher
if you can capture and use your own hand's image.
- Sit on the right side of your subject. Both you and your subject
should face the same direction.
- Have your subject turn over her or his right hand so that the
palm faces upwards.
- Place the print out of the hand over the subject's own hand.
Have the subject hold the picture with their left hand and position
it so that the picture aligns above the subject's real hand.
- With your right hand, gently touch the center of the image hand.
At the exact same time, with your left hand touch the center of
your subject's hidden hand.
NOTE: It is essential that the subject does not see you touching
their real hand. They will be aware of it, but should not see
it. The subject's observation should be limited to seeing you
touch the image of the hand.
- While keeping in constant contact, slowly move the position
of your finger. Try short and long brush-like strokes. Circle
your finger. It is important that the movement performed on the
image is duplicated on the subject's hand.
- After about 15 seconds, your subject may experience sensations
arising from your contact with the picture.
- Describe the subject's experience?
- Did the illusion of misplaced sensation occur immediately? Explain.
- Why was it important to conceal the movements of the researcher's
hand that was in contact with the subject's real hand?
In this activity, you explored how the brain might integrate a picture
of a matching hand into its dynamic concept of body image. But how
far could you push this connection? Would the subject feel the same
connection if a picture of a left hand covered the right hand? Suppose
a picture of a foot was placed over the subject's right hand? What
would happen then? Suppose a blank sheet of paper covered the hand.
Would the subject assign the sensation of detection to the paper?
Make a guess and with your instructor's approval try these simple
changes to your experimental design.
What do you know about acupuncture? What is its ancient and recent
history? Is it real or is it a sham? Use print and online resources
to learn more about acupuncture. Then, write the radio script for
a "public radio" show that explores acupuncture as both a valid
alternative medicine that produces self-healing and a pseudoscience.
Suppose you were in charge of introducing the placebo effect to
a group of traditional acupuncturists. What sort of challenges would
you face? Do you think that established acupuncturists would support
the effectiveness of acupuncture as a placebo? Why or why not? What
strategies would you use to best insure that your audience understood
and appreciated the implication of the research finds?
Placebo's Effect on the Brain
A popular press article that explores the placebo effect on treating
Placebo Acupuncture Needle
Study that explores the credibility of a placebo acupuncture needle.
- A Skeptic's View
A skeptical introduction to acupuncture.
Advisors for this Guide:
Suzanne Panico, Science Teacher Mentor, Cambridge Public Schools,
Anne E. Jones, Science Department, Wayland Middle School, Wayland,
Gary Pinkall, Middle School Science Teacher, Great Bend Public Schools,
Great Bend, KS