Visual Perception
In 1910, psychologist Max Wertheimer had an idea when he observed a series of lights flashing on and off at a railroad crossing. It was similar to how the lights encircling a movie theater marquee flash on and off. To the observer, it appears as if a single light moves around the marquee, traveling from bulb to bulb, when in reality it's a series of bulbs turning on and off and the lights don’t move it all. This observation led to a set of descriptive principles about how we visually perceive objects. These principles sit at the heart of nearly everything we do graphically as designers.
When human beings see a group of objects, we perceive their entirety before we see the individual objects. We see the whole as more than the sum of the parts, and even when the parts are entirely separate entities, we’ll look to group them as some whole. There are several key ideas behind gestalt and gestalt therapy.
Emergence is the process of forming complex patterns from simple rules. When attempting to identify an object, we first seek to identify its outline. We then match this outline pattern against shapes and objects we already know to find a match. Only after the whole emerges through this outline pattern matching, do we start to identify the parts that make up the whole. When designing, keep in mind that people will identify elements first by their general form. A simple well defined object will communicate more quickly than a detailed object with a hard to recognize contour.
Reification is an aspect of perception in which the object as perceived contains more spatial information than what is actually present. As we attempt to match what we see to the familiar patterns we have stored in memory, there isn’t always an exact match. Instead we find a near match and then fill in the gaps of what we think we should see. Reification suggests that we don’t need to present the complete outline in order of viewers to see it. We can leave out parts of the outline as long as we provide enough of it to allow for a close enough pattern match. You can see examples of this a little further down under the principle of closure.
Multi-stability is the tendency of ambiguous perceptual experiences to move unstably back and forth between alternative interpretations. Some objects can be perceived in more than one way. rom a design perspective if you want to change someone’s perception, don’t try to change it all at once. Find a way to get them to see an alternative. Then work to strengthen that alternative view, while weakening the original.
Invariance is a property of perception in which simple objects are recognized independent of their rotation, translation and scale. Since we often encounter objects from different perspectives, we’ve developed an ability to recognize them despite their different appearance. Imagine if you could only recognize someone you knew if they stood directly in front of you and faced you, but you couldn’t recognize them once they turned in profile. Despite the different visual perspective we can still recognize people.
Gestalt principles are important to understand. They sit at the foundation of everything we do visually as designers. They describe how everyone visually perceives objects. The principles above should be relatively easy to understand. For most of them, the definition and the image are probably all you needed to understand the principle. At the same time, understanding the basic ideas of these principles isn’t the same as understanding how they influence design.