Now You See It, Now You Don't! Test Your Peripheral Vision
David Whyte, PhD, Science Buddies
AbstractPeripheral vision is important in our everyday lives because it allows us to gather a visual sense of our surroundings—without it, we would see the world through "tunnel vision." The survival of our ancient ancestors depended on their ability to use peripheral vision to find prey and to avoid predators. Almost everything we do—from riding a bike, to dribbling a basketball, to reading a book—depends on peripheral vision. In this human biology science fair project, you will test the limits of peripheral vision and learn how to understand your results based on the anatomy of the human eye.
The objective of this human biology science fair project is to explore how the perception of objects, using peripheral vision, is influenced by the objects' shapes and colors.
Peripheral vision, or side vision, is the part of your vision that detects objects outside the direct line of vision. When you look at something, you use central vision to focus on the details, and peripheral vision to gather information about the surroundings. For example, your peripheral vision tells you where to look if someone enters the room, or if a car is approaching from the side. And as you read these words, you are using central vision to focus on a word or a few words, and peripheral vision to see where the words are within the sentence, the paragraph, and the page.
The light-sensitive lining at the back of your eye, called your retina, has light-receiving cells, called cones and rods. Only the cones are sensitive to color. Cone cells are most abundant in the central region of the retina, called the fovea. This region gives you the sharpest view of an object.
Rod cells are better at sensing objects in dim light than cone cells are, but they are not sensitive to color. Rod cells are also very sensitive to motion, and are responsible for your ability to detect things moving toward you before you can focus on them. This characteristic probably had strong adaptive value during the early stages of human evolution.
In this human biology science fair project, you will investigate the range of your peripheral vision, and determine how this range is affected by color, shape, ambient (meaning surrounding) light, and motion.
Terms and Concepts
- Peripheral vision
- Central vision
- Cone cells
- Rod cells
- What types of cells are responsible for peripheral vision, and how are they distributed in the retina?
- Why does an object need to come close to the center of your vision before you see its color and shape? (Hint: What part of your retina is receiving light from an object as it moves across your field of vision?)
- Why does it usually seem that our surroundings are clear and in focus, when in reality, only a small region of our visual field is in focus?
- How many rod and cone cells are there in the average human eye? How many of each cell type are there per square millimeter?
Materials and Equipment
- Elmer's® foam board, or other stiff material like poster board or cardboard (a 1.5 x 2-foot piece)
- Pushpin (1); the kind that sticks out, so you can tie a piece of string around it
- Scissors or X-ACTO® knife
- String (2 pieces: A 1 ½-foot piece and a 1-foot piece)
- Clear tape
- Small disposable paper or plastic cup
- Elmer's® glue
- Colored markers, several different colors
- Paper (5 sheets)
- Popsicle® sticks (about 12)
- Lab notebook
- To start this science fair project, you will first build a vision protractor. Place the foam board in front of you on a flat surface, with the long side closest to you.
- Stick the pushpin into the foam board, near the long edge and halfway along the 2-foot edge of the foam board. Be sure there is nothing underneath that will get harmed by the pushpin.
- Tie the 1 ½-foot piece of string to one end of the pencil, and tie the other end of the string around the pushpin.
- Now draw a half-circle with a 1-foot radius. Use your ruler to be sure your piece of string is 1 foot in length after you've tied the ends and before you begin drawing. Now shorten the string by tying more of the string around either the pencil or the pushpin, and draw another, smaller half-circle, with a ½-inch radius. Again, use your ruler to make sure the piece of string is ½ an inch long before you draw.
- Cut the half circles out of the foam board, as in Figure 1. The small circle should be just big enough for your nose.
- Place the protractor at the center of the small half circle. Tape the 1-foot-long piece of string at the 10° angle mark and extend the angle from the left side first. See Figure 1. Mark the edge of the foam board at the 10° mark. Repeat for angles from 10° to 90° for both left and right sides.
Figure 1. Vision protractor with plastic cup handle. Look at the focus point as a volunteer moves the colored object toward the center of your vision. Record the angle at which the object was first observed.
- Now stick the pushpin in at the edge of the half-circle, directly across from the nose hole. This will be your focus point. See Figure 1. Again, be sure it is not poking anything important underneath. You might want to use a piece of clear tape over top of it to secure it to the foam board so it does not fall out.
- Use glue to attach the plastic cup to the bottom of the foam board. The cup will serve as a handle, so should be glued somewhere near the center of the foam board. Now that you have made the vision protractor, it is time to make some colored objects to test your peripheral vision.
- Use colored markers to draw simple shapes, such as rectangles, squares, circles, and triangles, on the paper. You might start with objects about 1 square inch in area.
- Color the shapes in. Each shape should only be one color. Try red, green, and yellow. Alternatively, you can cut the shapes out of colored paper.
- Note the size and color of the shapes in your lab notebook. Create a data table, like the one below, in your lab notebook to plan your experiment before you begin. Write down the date and time, what objects you will be using, etc.
- Cut the colored shapes out. Attach the shapes to the Popsicle sticks with the clear tape.
- Now you are ready to start the experiments. Using the cup as a handle, hold the foam board base up to your face and put your nose in the center hole.
- Have your volunteer hold the popsicle stick with the attached shape so that it is perpendicular against the curved side of the base, starting at 0°.
Figure 2. Person looking at the focus point of a vision protractor while a volunteer moves an object slowly along the edge.
- Have your partner move the object slowly and evenly from the edge toward the middle while you keep your eyes on the focus point.
- Have your volunteer stop moving the object when you can first detect it, but both of you should stay where you are. Be sure to note the angle at which you first detected the object.
- It might be helpful to have a second volunteer write the angles down so that you don't have to stop the experiment to make notes in your lab notebook.
- Now have your volunteer keep moving the object toward the center of the foam board.
- This time, have your volunteer stop moving the object when you can first detect the color of the object. Again, note the angle at which you first detect the color of the object in your lab notebook.
- Have your volunteer continue moving the object and note the angle at which you first can make out the shape of the object.
- Repeat steps 14-22 two more times with the first object. Then repeat steps 14-22 three times for each additional object. You should end up with at least three readings for each trial.
Here are some questions you might want to focus on:
- What color does your peripheral vision respond to best? (What color did you expect to be the easiest to detect?)
- What color was the hardest to see using peripheral vision?
|Date and Time:|
|Participants: Who is moving the object, who is observing, etc.|
|Goal of This Experiment: For example, to test different colored objects, etc.|
|Notes: Add notes about the procedure. Remember to record your data and observations so that someone else could reproduce your results.
(shape, color, etc.)
|Angle First Observed||Comments |
(For example: "Aunt Bessie was the test subject for this set of experiments"; "The light was turned down in this set of experiments"; "This is the second trial of three total for this object."
|Red triangle, 1 inch||22 degrees||Trial 1:|
|Red triangle, 1 inch||23 degrees||Trial 2:|
|Red triangle, 1 inch||21 degrees||Trial 3:|
|Red triangle, 1 inch||22 degrees||Average for Red triangle, 1 inch:|
|Blue circle, 2 inches|
Table 1. Use a data table similar to this one to record your observations. Use the data table to plan your experiments before you start. Make separate data tables for different experiments if that helps you organize your data.
Ask an Expert
- Repeat the experiment with different-sized objects. Graph the size vs. the angle at which each one was first detected by your eye.
- Try this experiment in light that is either dimmer or brighter than the lighting for the first experiment. Use a light meter to quantify the level of light. Make a graph of light level vs. angle of first observation.
- Try running the experiment with the volunteer gently shaking each object as he or she moves it along the foam board. How does this affect your angles of first observation?
- Test the peripheral vision of a number of people to determine the influence of age, gender, eye color, color blindness, etc. on peripheral vision. Check with your science teacher to see if you are required to obtain written consent prior to recruiting people for your experiments, and read over the helpful notes in Projects Involving Human Subjects on the Science Buddies website.
If you like this project, you might enjoy exploring these related careers:
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