Background

The Gestalt psychologists, especially Max Wertheimer, developed a number of “laws” that predict how perceptual grouping occurs under a variety of circumstances (Wertheimer, 1923/1938). Technically, in sciences, laws are predictions that are true. In reality, these laws are better classified as principles, which are true most of the time. However, the term law has stuck with these principles because they were established so long ago. So we will continue to refer to them as laws, even though technically they are not scientific laws.

Law of Common Fate is the gestalt grouping law that states that elements that are moving together tend to be perceived as a unified group. Think of watching a flock of geese moving across a fall sky. The geese are all flying the same direction at approximately the same speed. Therefore, we see them as a gestalt group, or in this case, a flock. We might see a second flock flying in a different direction in a different pattern.

Use this activity to explore how the Law of Common Fate operates.

Instructions

Full Screen Mode

To see the illustration in full screen, which is recommended, press the Full Screen button, which appears at the top of the page.

Illustration Tab

Settings

Below is a list of the ways that you can alter the illustration. The settings include the following:

Correlation: choose how much together the gestalt dots move in the same direction. Increasing this correlation makes the dots move more in the same direction. Decreasing this value makes the getstalt dots move more randomly relative to each other.
Direction: the higher this value, the more the gestalt group moves in a line. The lower this value, the more the gestalt groups moves just randomly.
Back Dir: the higher this value the more the dots that are not part of the gestalt group move in a line. The lower this value, the more they just jiggle randomly.
Color: change the color of dots that are part of the gestalt group.
Shape: change the shape of dots that are part of the gestalt group. The higher the value, the more these dots are circles like the rest of the dots. The lower the value, the more the gestalt grouping dots are squares.

Reset

Pressing this button restores the settings to their default values.