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The Brains Behind 'Where's Waldo?'

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Abstract

What makes you notice someone in a crowd? Why do some things stand out, while others melt into the background? In this science project you can investigate the psychology of how things get noticed, by studying how our brains perform a visual search.

Summary

Areas of Science
Difficulty
 
Time Required
Very Short (≤ 1 day)
Prerequisites
None
Material Availability
Readily available
Cost
Very Low (under $20)
Safety
No issues
Credits

Sara Agee, Ph.D., Science Buddies
Teisha Rowland, Ph.D., Science Buddies

Objective

Test if changing the number of distracters will affect the ability of an observer to find a certain target during a visual search.

Introduction

Have you ever looked and looked desperately for something? It is so frustrating! The classic example is when I lose my keys. You would think that by now (knowing that I am the kind of person who often loses my keys) I would have a huge, bright red key chain with a blinking strobe light that plays a ring tone every time I lose them. But of course, I still have them on a plain-old key ring. Hence the frustration.

But I can turn this story from lemons into lemonade. It turns out that this frustrating situation is the perfect example of performing what cognitive psychologists call a visual search. During a visual search, an observer (me) looks for a target (my keys) in the midst of distracters (all of the other stuff in my messy house). By making my key chain easier to see, I could have improved upon my visual search, and made my search more successful.


What properties are important for performing a successful visual search? Try this quick activity to help you think about the variables. In which of the two images in Figure 1 below can you find the red letter "T" the fastest?
Two sets of images show a red T next to blue L's on the left and a red T next to red L's and blue T's on the right
Figure 1. Which side has the easier task? (Busey, date unknown)

It was probably the image on the left. The image on the right has more complex distracters than the image on the left, making finding the target (the red letter "T") more difficult. In this human behavior science project you will use an online program to design your own visual search experiments to test whether changing the number of distracters will affect your visual search. Will increasing the number of distracters make your search more difficult?

Terms and Concepts

Questions

Bibliography

This science project uses an online Visual Search test written by Dr. Tom Busey at the Indiana University, Bloomington:

  • Busey, T. (n.d.). Visual Search. Cognitive Science Software, Department of Psychological and Brain Sciences, Indiana University, Bloomington. Retrieved January 22, 2013.

You can do further research by visiting the following websites, which give information about doing a visual search:

Two classic children's book series that are based upon the Visual Search Principle are the "Where's Waldo" and the "I Spy" books. Here is the original book from each series for you to check out:

  • Handford, M., 1987. Where's Waldo?, New York, NY: Little Brown & Co.
  • Marzollo, J., 1992. I Spy: A Book of Picture Riddles, New York, NY: Scholastic.

Materials and Equipment

Experimental Procedure

  1. In your web browser, go to the Cognitive Science Visual Search page developed by Dr. Tom Busey.
  2. Depending upon your operation system and what Internet browser you have and whether the necessary Java is enabled on your computer, you will either be able to run the Java applet directly from the webpage or need to download the software on your computer before using it. Many modern browsers have trouble running Java applets due to security settings, so you may need to use the downloadable version.
    1. To use the Java applet simply select the "Run Applet" button (under "Software").
    2. Or to download the software, click on the movie link and follow the instructions to download the software to your desktop. As mentioned in the instructions, you need to make sure that the VisualSearch.jar file and the unzipped target folder with the images are both in the same location on your hard drive. When opening the target folder, you should be able to see the image files you need. Note: Sometimes, the unzipped target folder contains another target folder, that contains the images. If this is the case, move all the images up to the highest level in the target folder. You want only one level of hierarchy in your target folder structure [target/images, NOT target/target/images].
    3. After you have downloaded and copied the necessary files, start the Visual Search Experiment by clicking on the Visual Search icon on your desktop or by double-clicking the VisualSearch.jar file. Note: If you are using a Macbook, the computer might tell you it can't find the target folder even if it is in the same location as the VisualSearch.jar file. If that happens, you will have to run the application from your computer terminal. Open the terminal, which you can find in the Utilities folder in your Applications. Make sure you have the unzipped target folder with your images and the VisionSearch.jar file both in the Download folder. Then type the following command to run the program (you will have to enter the name of your home folder in the command):
      1. To access the Download folder, type: cd /Users/type in your home folder name here/Downloads. Then press enter.
      2. To run the program, next, type: java -jar VisualSearch.jar. The application should now start.
  3. Once the Visual Search applet or downloaded program is running, select the "Targets" tab at the top. Your page should look like Figure 2 below.
Screenshot of the program Visual Search

Screenshot of the program Visual Search shows a Targets page with 4 images selected and set to different colors. The top of the page has 8 tabs to choose between (the current tab is "Targets"). On the Targets page there are 4 areas to choose different targets with options to change the target and set it to a specific color.


Figure 2. Selecting the "Targets" tab should take you to a screen that looks like this.
  1. In the "Target 1" section click on the large drop-down menu and select the image you want to make your target, such as the hotdog, as shown in Figure 3 below. (The images are arranged alphabetically.)
    1. For the target, we recommend using one of the images of the food items, such as the burger, donut, peas, etc.
Screenshot of the Targets tab in the program Visual Search

Screenshot of the program Visual Search shows a Targets page with the first target image being changed. On the Targets page there are 4 areas to choose different targets with options to change the target and set it to a specific color. A drop-down menu is opened by clicking the arrow next to the first target image. A hotdog.gif file is selected for the first target.


Figure 3. Select the target image you want to use from the Target 1 section's drop-down menu. In this example the image of a hotdog is being used as the target image.
  1. Once you select the new target, you should see its image in the box for Target 1, as shown in Figure 4 below.
    1. Make sure that the box by "Display Target 1" is checked and that the boxes next to Targets 2-4 are unchecked.
    2. You can ignore Targets 2-4 because they are unchecked and will not show up in your experiment.
Cropped screenshot of a target in the program Visual Search

Screenshot of the Visual Search program shows a Targets page with the first target image color being changed. The first target image is a file named hotdog.gif and the current color option beneath the image is set to yellow.


Figure 4. Once you have selected a target image, such as the image of a hot dog, it should appear in the box in the Target 1 section.
  1. Now click on the "Distracters" tab at the top. Just like with the Targets tab, in the "Distracter 1" section click on the drop-down menu and select the image you want to make your distracter, such as the burger, shown in Figure 5 below. Once you select the distracter, you will see it in the Distracter 1 box.
    1. For the distracter, we recommend using one of the images of the food items, such as the burger, donut, peas, etc.
    2. Make sure the distracter you select is different from the target you selected.
    3. Confirm that the box by "Display Distracter 1" is checked and that the boxes next to Distracters 2-4 are unchecked.
Cropped screenshot of a distractor in the program Visual Search

Screenshot of the Visual Search program shows a Distractor page with the first distractor image set to a file named burger.gif. The first distractor images current color option is set to black.


Figure 5. Once you have selected a distracter image, such as the image of a burger, it should appear in the box in the Distracter 1 section.
  1. Next click on the "Do Experiment" tab, which should look like Figure 6 below. Be sure the "Use Circular Display" box is UN-CHECKED! Then click on the "Start Experiment" button and follow the instructions.
    1. In the experiment, press "f" is you see the target or "j" if you do not see it.
    2. Tip: Make sure nothing distracting is going on around you when you do the experiment!
Cropped screenshot of the Do Experiment tab in the program Visual Search

Screenshot of the Visual Search program with the "Do Experiment" tab selected. The window includes options including: Trials of Target Present, Trials of Target Absent, Number of Rows and Columns, Number of Targets at Once, Amount of Jitter in Pixels and Separation of Items. The window also includes an unchecked option to "Use Circular Display", and options to set Radius of Circular Display and Number of Stimuli in a Circular Display.


Figure 6. In the "Do Experiment" tab be sure that the "Use Circular Display" box is unchecked and then click the "Start Experiment" button.
  1. When you are done, it will instruct you to click on the button below to quit and view your results, which will show up on the "Do Experiment" screen, as shown in Figure 7 below. Do not pay attention to your results yet. Instead, repeat step 7 two more times, or until you feel comfortable with doing the experiment, and then continue on to step 9.
    1. By getting familiar with the experiment process (step 7) before doing the actual experiment, this will help prevent any unfamiliarity with the process from affecting your results.
Cropped screenshot of experiment results in the program Visual Search

Screenshot of the Visual Search program results page. The results are split into four sections: correct trials, incorrect trials, all trials and all trials accuracy. The data presented in the results page show the accuracy of the trials as well as the average reaction times for each trial.


Figure 7. After you have done the experiment, your results will show up on the "Do Experiment" screen.
  1. After becoming familiar with the experiment process, repeat 7 again.
  2. This time when you get the results of the experiment, write down the numbers in the "Mean Reaction Times for Target Present Trials" and "Mean Reaction Times for Target Absent Trials" boxes under "All Trials." (Ignore the numbers in parentheses.)
    1. Record your results in your lab notebook in a data table like Table 1 below.

Number of Distracters Type of Distracter Mean Reaction Times for Target Present Trials Mean Reaction Times for Target Absent Trials Average Reaction Time for the Different Number of Distracters
1 burger      
2 pizza      
3 etc.      
4 etc.      
Average Reaction Time for Target Present Vs. Target Absent      
Table 1. In your lab notebook, create a data table like this one to record your results in.
  1. Now go back to the "Distracters" tab and add another distracter.
    1. To add Distracter #2, check the "Display Distracter 2" box, and then select a distracter, such as pizza, from the drop-down menu, as shown in Figure 8 below.
    2. For each distracter, we recommend using one of the images of the food items, such as the burger, pizza, donut, peas, etc.
    3. Make sure the distracter image you select is different from the target and previous distracter image you selected.
Cropped screenshot of a distractor in the program Visual Search

Screenshot of the Visual Search program shows a Distractor page with the second distractor image set to a file named pizza.gif. The second distractor images current color option is set to blue.


Figure 8. Add a second distracter by selecting an image in the Distracter 2 section.
  1. Click on the "Do Experiment" tab, click "Start Experiment," and follow the instructions. Record the results in your data table as you did in step 10.
  2. Repeat step 11 but now add a third distracter. Then repeat step 12.
  3. Repeat step 11 but now add a fourth distracter. Then repeat step 12.
  4. Repeat steps 7 to 14 with at least four more people, and record the results of each volunteer in a data table like Table 1. (Each volunteer will need a different data table.)
    1. Be sure that the correct distracters are selected to display for each experiment. You will want to start each volunteer with one, then two, then three, then four distracters, just as you did when doing the experiment on yourself.
    2. Select the same distracter images (and in the same order) for each volunteer.
  5. When you are done, calculate each volunteer's (including your own) average reaction time for when the target was present and calculate their average reaction time for when it was absent. Record your results in the bottom row in your data table, which should be labeled "Average Reaction Time for Target Present Vs. Target Absent," as shown in Table 1.
    1. To calculate each volunteer's average reaction time for when the target was present, add together the four reaction times in the "Mean Reaction Times for Target Present Trials" column and divide this answer by four.
    2. To calculate each volunteer's average reaction time for when the target was absent, add together the four reaction times in the "Mean Reaction Times for Target Absent Trials" column and divide this answer by four.
  6. Now calculate the average reaction time for all five volunteers for when the target was present and when it was absent. Write your (two) answers in your lab notebook.
    1. To calculate the average reaction time for all five volunteers when the target was present, add up your answers from step 16a (for each of the five volunteers) and divide this answer by five.
    2. Similarly, to calculate the average reaction time for everyone when the target was absent, add up your answers from step 16b (for each of the five volunteers) and divide this answer by five.
  7. Next calculate the average reaction time each person had for the different number of distracters. Record your results in the far right column in your data table, which should be labeled "Average Reaction Time for the Different Number of Distracters," as shown in Table 1.
    1. To calculate each person's average reaction time for the different number of distracters, add together the two reaction times for a given number of distracters. (Add together the "Mean Reaction Times for Target Present Trials" and "Mean Reaction Times for Target Absent Trials" in each distracter's row.) Divide this answer by two.
      1. For example, if when three distracters were present a volunteer had a mean reaction time of 880 when the target was present, and a mean reaction time of 1100 when the target was absent, you would add these numbers up to get 1980. Since 1980 divided by two is 990, then 990 would be your average reaction time for this volunteer for when three distracters were present.
  8. Now calculate the average reaction time for all five volunteers for the different number of distracters. Write your (four) answers in your lab notebook. In your lab notebook, you may want to create a data table like Table 2 below to record your results in.
    1. To calculate the average reaction time for all five volunteers for the different number of distracters, add up your answers from step 18a for each different number of distracters. Then divide this number by five to calculate the average for all volunteers.
      1. For example, if the average reaction time for one distracter was 610 for your first volunteer and 522, 729, 680, 720 for the other four volunteers, you would add these numbers up to get 3261. Since 3261 divided by five is 652, then 652 would be your average reaction time for one distracter.

Number of Distracters Type of Distracter Average Reaction Time for All Five Volunteers
1 burger  
2 pizza  
3 etc.  
4 etc.  
Table 2. In your lab notebook, you may want to create a data table like this one to record your average reaction time calculations for the different numbers of distracters.
  1. Make two bar graphs of your data. Make one graph showing the average reaction time when the target was present versus when it was absent and make a second graph showing the average reaction time for the different number of distracters.
    1. For the first graph, use the (two) numbers you calculated in step 17. Label the bars on the x-axis (the horizontal axis) as either "Target Present" or "Target Absent." Label the y-axis (the vertical axis) the "Average Reaction Time." Make a bar for each result up to the corresponding average reaction time.
    2. For the second graph, use the (four) numbers you calculated in step 19. Label the x-axis the "Number of Distracters." Label the y-axis the "Average Reaction Time." Make a bar for each number of distracter (1, 2, 3, and 4) and make the bar go up to the corresponding average reaction time.
  2. Analyze your graphs.
    1. Did the volunteers react faster or slower when the target was absent (compared to when the target was present)?
    2. Did the volunteers react faster or slower as the number of distracters increased?
    3. Were your findings fairly consistent from volunteer to volunteer, or did you see some differences? Why do you think this might be?
    4. What do your results tell you about the most successful conditions for doing a visual search?
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Ask an Expert

Do you have specific questions about your science project? Our team of volunteer scientists can help. Our Experts won't do the work for you, but they will make suggestions, offer guidance, and help you troubleshoot.

Variations

  • You can change other variables as well. Here are some ideas to try:
    • Change the number of targets instead of distracters
    • Measure percent correct instead of the reaction time
    • Change the number of images by changing the number of rows and columns
    • Use different symbols, like letters or numbers
    • Change the colors of the target and distracters
  • Can you think of real world applications for this cognitive test? See if you can investigate the use of visual search properties in any of these areas:
    • Designing logos and brand names to be noticed
    • Designing web pages that are easy to navigate
    • Finding points of interest on a map
    • Displaying data in a way that shows what is important
    • Any other application that you can imagine— just think of a way to test it!

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General citation information is provided here. Be sure to check the formatting, including capitalization, for the method you are using and update your citation, as needed.

MLA Style

Science Buddies Staff. "The Brains Behind 'Where's Waldo?'." Science Buddies, 8 Dec. 2021, https://www.sciencebuddies.org/science-fair-projects/project-ideas/HumBeh_p032/human-behavior/brain-function-where-is-waldo. Accessed 19 Mar. 2024.

APA Style

Science Buddies Staff. (2021, December 8). The Brains Behind 'Where's Waldo?'. Retrieved from https://www.sciencebuddies.org/science-fair-projects/project-ideas/HumBeh_p032/human-behavior/brain-function-where-is-waldo


Last edit date: 2021-12-08
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