The "Aha!" Response
An object that has bilateral symmetry can be divided into mirror images by drawing one vertical line through the center. In other words, if a vertical line were drawn dividing the object in half, the left and right sides would match each other. Most animals, and some plants, have bilateral symmetry. Animals with a bilaterally symmetrical nervous system are those in which the parts of the nervous system on the right and left sides of their bodies are mirror images of each other.
When confronted with alternatives, animals with bilaterally symmetrical nervous systems can learn to make consistent choices. Sometimes, learning is a response to a particular stimulus or to a reward. Other times, learning comes through force of habit, or trial and error, or insight.
In this project you will study the human ability to learn by trial and error as well as through insight. The ability of mice and insects to learn as a result of operant conditioning—that is, to learn as a result of receiving rewards for desired behavior—will be determined. You will also look at factors that may affect the retention and rate of learning, such as practice and distractions.
Purpose: To determine the time it takes for a person to trace the mirror image of a pattern.
- 20-by-24-by-36-inch (50-by- 61-by-90-cm) cardboard box
- box cutter
- 24-by-16-inch (60-by-40-cm) mirror
- duct tape
- felt-tip marking pen
- 10 copies of test sheet (Draw your own. See Figure 21.2)
- 10 test subjects
- Build a mirror test box (see Figure 21.1). Note: The size of the box and mirror are not critical. You want a box and mirror large enough to allow each test subject to see only the mirror image of the pattern and be able to insert his or her hand without restriction to trace the pattern. Here are the steps followed by the author in building a test box using the listed materials.
- In the front wall of the box, 4 inches (10 cm) down from the top, use the box cutter to cut a 20-inch (50-cm) slit across the center of the box.
- In the back wall of the box, 17 inches (43 cm) down from the top, cut a 20-inch (50-cm) slit across the center of the box.
- Insert the edges of the mirror (facedown) through the slits in the front and back walls of the box.
- Use duct tape to secure the edges of the mirror to the box.
- Cut a 16-by-16-inch (40-by-40-cm) square out of the front wall of the box. Make sure this hole is centered and its top edge is about 4 inches (10 cm) below the edge of the mirror (see A in Figure 21.1).
- Cut a 4-by-12-inch (10-by-30-cm) section from the bottom edge of the front wall of the box (see B in Figure 21.1.)
- To allow viewing light to enter, cut out one 12- inch (30-cm) square from each side of the box with the lower edge of the square about 4 inches (10 cm) from the bottom of the box (see C in Figure 21.1).
- Set the mirror test box on a table.
- Lay the marking pen and one copy of the test sheet inside the box. (see Figure 21.2).
- Have the test subject sit in a chair positioned in front of the test box.
- Read the following instructions to one test subject:
- Follow the instructions as I read them to you.
- Insert your hand through the opening at the bottom of the box.
- Look at the mirror through the opening in the center of the box.
- The objective is for you to use the pen to draw a line through the center of the path on the test sheet as fast as possible without crossing the printed lines of the pattern. When I say "Get ready … Start," you will begin and I will start the timer. When you finish, say "Stop" and the timer will be stopped.
- Place the tip of the pen on the word "Go" on the sheet.
- Get ready.
- Repeat the procedure for all of the test subjects.