ANDREW S. GIBSON, DIGITAL PHOTOGRAPHY SCHOOL:
"Gestalt theory evolved in the 1920’s to explain some of the ways in which people perceive the world around them. The basic idea is that, when faced with a visually chaotic scene, the human mind simplifies it into more recognizable patterns and shapes.
"Gestalt theory provides an insight into the pattern recognition process that occurs when people look at photographs. Once you understand the principles of gestalt theory, you can use them to improve the composition of your photos."
Learn more, here.