Studying Visual Trickery with the McCollough Effect

based on 42 ratings
Author: Megan Doyle

Grade Level: 6th to 8th; Type: Social Science


The objective of this experiment is to identify which types of people are most impacted by the McCollough effect.

Research Question:

  • Who is impacted most by the McCollough effect?

The McCollough effect is a phenomenon of visual perception. Colorless images will appear to have color after a person spends time studying an induction image. The duration of the McCollough effect varies from person to person. In this experiment, you will identify a population of test subjects that experiences this effect for the longest amount of time. What do these subjects have in common?


  • Test subjects
  • Online demonstration of the McCollough effect
  • Stopwatch
  • Notebook for recording results

Experimental Procedure:

  1. Recruit many male and female test subjects in a variety of age groups.
  2. Ask a test subject to study the online animation meant to stimulate the McCollough effect for exactly seven minutes.
  3. After seven minutes, start your stopwatch and ask the test subject to let you know when the McCollough effect has worn off.
  4. Record this time and make a note of the test subject’s age and gender.
  5. Repeat steps 2-4 with all of your test subjects.
  6. Analyze your results. What was the average duration of the McCollough effect in male test subjects? In female test subjects? What was the average duration of the McCollough effect in test subjects younger than thirty? Older than thirty? Look at the participants that experienced the McCullough effect for the longest amount of time. What do they have in common?

Terms/Concepts: McCollough effect

Reference: “McCollough Effect.”

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