The law of common fate is one of four visual perception laws as theorized by gestalt psychologists. Paul Martin Lester, the author of Visual Communication, an expert in the field wrote: "The fourth law of Gestalt psychology is the law of common fate. A viewer mentally groups five arrows or five raised hands pointing to the sky because they all point in the same direction. An arrow or a hand pointed in opposite direction will create tension, because the viewer will not see it as part of the upwardly directed whole."
Gestalt's law of common fate is a pretty simple concept. It is basically referring to visual directional lines within a design or layout. In a photograph, if two or more people are moving in the same direction, they have created a directional line known as the law of common fate. Together, they have a common fate or destiny. Another example of the law of common fate could include similar shapes aimed in the same direction. You might wonder why the law of common fate is of importance to artists. First of all, when two objects (whether it be shapes or organic forms) are pointed in the same direction in a layout, the directional lines become dominant in a design. So, if two or more powerful shapes are aimed at or moving in a certain direction, an artist knows to put the message at the point of destination.
Directional lines push our eyes around a page. This can be a problem every bit as much as bonus. For instance, visual collisions frustrate the viewing audience. It can cause too much tension and cause anxiety for the reader which in turn, makes the layout uninviting and too intense.
If a candid photograph of a moving car is heading to the right, the law of common fate dictates that the directional line is pointing to the right. Then again, if a candid photograph of a car is aimed towards the left and the image is part of a design, the directional line is now aimed towards the left. Therefore, if a car is headed towards the right (on an image), the image of the car should be placed towards the left-hand side of a layout, because our eyes read from left to right. This is why the law of common fate is so important. The law of common fate should not be ignored in graphic designs and advertisements. Understanding the law of common fate and how directional lines work on layouts can make all the difference in how information is read and understood.