This activity page will offer:

• Insight into echolocation
• Hands-on/minds-on activity in reflected sound waves
• Experience in calculating distance based upon detection of reflected sound waves

Mind Over Reality?
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 reality.

Materials

• Printout of hand

• Digital Camera (optional)

Steps (For the set-up)

1. Work with a partner. Chose one person to be the subject and one person to be the tester
2. 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.
   
   
3. Sit on the right side of your subject. Both you and your subject should face the same direction.
4. Have your subject turn over her or his right hand so that the palm faces upwards.
5. 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.
6. 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.
   
   
7. 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.
8. After about 15 seconds, your subject may experience sensations arising from your contact with the picture.
   

Questions

1. Describe the subject's experience?
   
2. Did the illusion of misplaced sensation occur immediately? Explain.
   
3. Why was it important to conceal the movements of the researcher's hand that was in contact with the subject's real hand?
   

Stretching the Point
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.

Acupuncture
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.

A Placebo Switch
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?

Web Connection

The Placebo's Effect on the Brain
http://www.placebo.ucla.edu/news/PDF/dallasmn020121.pdf
A popular press article that explores the placebo effect on treating depression.

New Placebo Acupuncture Needle
http://www.acupuncturetoday.com/archives2002/
apr/04needle.html
Study that explores the credibility of a placebo acupuncture needle.

Acupuncture - A Skeptic's View
http://www.theness.com/encyc/acupuncture-encyc.html
A skeptical introduction to acupuncture.

Academic Advisors for this Guide:
Suzanne Panico, Science Teacher Mentor, Cambridge Public Schools, Cambridge, MA
Anne E. Jones, Science Department, Wayland Middle School, Wayland, MA
Gary Pinkall, Middle School Science Teacher, Great Bend Public Schools, Great Bend, KS