OBJECTIVE
These activities will offer:

• a hands-on experience during which you'll try to tickle yourselves
• experiences that test how spoken and tactile directions may interfere with the tickle sensation

A Ticklish Subject

MATERIALS

• Makeup pencil
• Makeup remover
• Paper and marker
• Paper and pencil (to record your observations)

PROCEDURE

Part 1 - Tickling - Out of Control

1. Work with a partner - one person is the "researcher" and the other is the "subject".
2. As the researcher, ask your subject to remove his/her sock and shoe from one foot.
3. Ask the subject to try to tickle himself or herself by gently brushing fingers over the exposed arch in a manner that would elicit a tickling response in others.
4. Next, explore the tickling response by gently brushing your fingers over the subject's exposed arch.
5. Using a ruler as a guide, draws a 3" by 3" grid on a sheet of paper. Each grid line should have a separation distance of 1 inch = producing 9 equal sized squares. Over the top row, identify each column as A, B, and C. Along the left margin, identify each row as 1, 2, and 3.
6. Note how each box can be identified by a letter and number combination. A1 is the top left box. The center box is B2.
7. Uses a makeup pencil to reproduce a copy of this box on the exposed arch of your subject. The box drawn upon the skin must be created at the same size as this paper version.
8. Ignoring the line pattern, the researcher brushes a random pattern across the grid. REMEMBER: The random brush strokes cannot extend beyond the center of the outlying boxes as illustrated - the "area of allowable tickling."
9. Your subject should rate the ticklish stimulation on a scale of 1 to 10 and record it in their journal.
10. Place a finger at the center of any one of the boxes. Steadily, brush your finger against the skin in a controlled manned, from to the center of one adjoining box to the next. Again, your subject should rates this more controlled brush on a scale of 1 to 10.
11. Now move your finger around the grid more randomly, without moving box to adjoining box, but always remain within the "allowable area of tickling." Ask your subject should compares and contrasts the intensity of the tickle and record this in their laboratory journal.
12. Exchange roles with the subject and repeat the activity.

PART 2 - TICKLING - Audio Directed Paths

PROCEDURE

1. Ask your subject to hold the grid made in the previous activity and call out the identity of one of the squares. Lightly presses a finger in the center of that square.
2. The subject should identify a neighboring square. In response gently brush a straight line to the center of this square. Ask the subject to compare and contrast this self-directed movement to the random movement produced in the previous activity. The subject should rate the tickle stimuli on a scale of 1 to 10.
3. Ask the subject to call out a succession of box destinations, given just as the finger reaches the center of its intended box. This will create a continual and slow movement from box to box. Afterwards, ask the subject to compare the ticklish stimulus of this subject-directed movement to the researchers random movement from box center to box center, on a scale of 1 to 10.
4. Exchange roles and repeat the activity.

PART 3 - TICKLING - Tactile Directed Paths

1. Ask your subject should hold the grid paper in one hand so that both of you can see this grid. Ask the subject to use his/her other hand to point to a grid location and maintain continual contact between the fingertip and the paper.
2. As the subject points to the paper grid position, place a finger on the arch grid at that same location.
3. Keeping contact with the paper, the subject should slowly draw a path from box to box. Simultaneously, brush the same pattern onto the arch grid. Ask the subject to compare, contrast, and rate this tactile directed stimulation with the previous tickling methods.
4. Exchange roles and repeat the activity.

QUESTIONS

1. Was self-tickling experienced?
2. Why was the random tickling movements restricted to a certain area that was one half inch within the outer perimeter of the grid?
3. How did directing the tickle movement by spoken locations affect the tickle?
4. How did directing the tickle movement by drawing out movements by the subject's finger affect the tickle? Why?

CRITICAL ANALYSIS OF YOUR MODEL

Why does directing your own tickle movements reduce the tickling sensation? Did you and your partner have the same responses? Compare and contrast these trials performed by other classmates? Are some people more ticklish than others are? Can you uncover and personality or biological features that may influence a person's response to tickling?

EXTENSIONS

Can preoccupation with another thought affect your ability to be tickled? Think about it. Suppose you were in the midst of mathematical calculations. Would this thinking interfere with your brain's response to the potentially tickling stimuli? Design an experiment that would explore how preoccupation with other thoughts affects one's ability to be tickled. With your instructor's approval, perform the inquiry and share your results with the class.

TICKLED WITH YOUR OWN FINGER

Here's a challenge. Do you think that you can be tickled with your own finger if someone else controls its movements? To check this out, you'll need to relax enough so that your partner moves your finger without any resistance. First, remove your shoe and sock. Cross your legs so that your left foot extends horizontally across your right thigh. Have your partner sit on your right side. Let them take your right hand and hold it so that your index finger extends outward. Relax and give up control of your right arm, finger, and hand. Challenge your partner to tickle your exposed arch using your index finger. Can it be done? Even though you are not in control of the movements, does your body have automatic feedback that tells you where and what your body parts are doing?

WEB CONNECTION

Journal American Scientist
An excerpt from an article entitled The Mystery of Ticklish Laughter

Self-tickling
This article explains the role of the cerebellum in preventing self-tickling

Nature News Service
Describes experiments on self-tickling

The activities in this guide were contributed by Michael DiSpezio, a Massachusetts-based science writer and author of "Critical Thinking Puzzles" and "Awesome Experiments in Light & Sound" (Sterling Publishing Co., NY).

Academic Advisors for this guide
Corrine Lowen, Science Department, Wayland High School, Wayland, MA
Suzanne Panico, Science Department, Fenway High School, Boston, MA

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