The law of similarity in gestalt theory states that elements that look similar to each other are grouped together in the mind.
A similarity gestalt example is when you walk into a hipster bookstore and the books have been organized by color rather than practicality.
Instead of grouping books by topic, the hipster has grouped elements by appearance. They’ve let the law of similarity get in the way of a hypothetical law of practicality!
Law of Similarity (Gestalt Theory) Explanation
When we see an image that contains individual elements that look the same, then we perceive those elements as belonging in the same group.
For example, the image below demonstrates similarity based on color and shape.
In general, people will:
- See the elements in the left array as being in two groups, green and blue.
- See the elements in the middle array as falling into two categories, circles and squares.
- See the elements in the right array as falling into color categories. Even though the images differ in two dimensions, to most people, color wins as the most salient.
The more similar the elements, the more likely they will be grouped together in our mind and perceived as belonging to the same category.
Law of Similarity Examples
- In game design, monsters of equal value when destroyed are the same color.
- In app design, navigation is made easier by using color markers to help users find the content they want.
- All the apps on a smartphone are represented by circular icons.
- The button for adding an item to the shopping cart on an
e-commerce site is the same size and color on every page.
- In some NFL playbooks, same player positions are depicted by same shaped icons. Linemen are squares, running backs are triangles, receivers are ellipses, and the quarterback is a star.
- This calendar on a phone automatically makes the dates of the current week brighter than the rest of the numbers. Plus, that day’s date is encircled by a different color to make it distinct from the group.
- Some grandparents like to wear the same-colored shirts when traveling as tourists. This way, the locals can tell they are together and won’t try to hit on them.
- While most players on a soccer team wear the same color jersey, the goalkeeper always wears a different color. This makes it easy for the players to identify who they can run into and who they can’t.
- When designing a menu, different food options are in one color, while different beverage options are in a different color.
- Television and digital media advertising often display information about product features in one color, and special offers and discounts in another.
- The law of similarity is one of five laws or principles in gestalt theory that identify how perceptual processing occurs. The others are: proximity, continuity, connectedness, and closure.
- There are several other principles that identify how perceptual processing occurs. They outline how complex images, which contain lots of individual elements, are interpreted in the mind as a whole image.
- These principles are summarized with the well-known saying, “the whole is greater than the sum of its parts.”
- Gestalt theory was formulated by Max Wertheimer, Wolfgang Kohler, and Kurt Koffka. Their perspective was in direct contrast to the structuralist orientation popular in psychology at the time.
- For instance, psychologists such as Wilhelm Wundt attempted to study phenomenon in the smallest unit of analysis possible.
- The Gestalt movement offered the study of psychology an additional approach to understanding people, their thoughts, feelings, and cognitive processes.
Other Gestalt Theory Principles
The Gestalt theory principles refer to how human beings perceive visual stimuli.
The fundamental principles are:
- Proximity: Individual elements of a visual stimulus that are close together are perceived as being related.
- Continuity: Individual elements that are arranged in a manner in which they could be connected by a smooth and continuous line are followed by the eye and perceived as a whole.
- Similarity: Elements that are alike tend to be grouped together.
- Connectedness: Individual elements that are connected are perceived as more related than elements that are not connected.
- Closure: If an image contains missing parts, perceptual processes tend to fill in the gaps to complete the image and make it whole.
Case Studies of the Law of Similarity
1. Knowledge Maps and Gestalt Principles
Teachers often use knowledge maps, or concept maps, to help students understand how concepts are interconnected. These maps provide a graphical representation of how knowledge is organized and are very effective in helping students learn and retain information.
There are many ways to design a knowledge map. Wallace et al. (1998) were interested in applying the Gestalt principles of proximity and similarity to examine if incorporating these principles would enhance learning.
The researchers asked university students to study the same content. Some studied the content via text. Others studied the content presented in the form of a typical knowledge map, or an enhanced map.
The enhanced maps added color, shaping, and groupings based on the Gestalt principles of proximity and similarity.
Two weeks later, students took a free recall test.
“Students who had studied enhanced maps recalled more information than the students who had studied unenhanced maps or text. The results suggest that the use of color, shape, and proximity facilitated learning by improving the organization of information” (p. 5).
2. Tourism Logos and Gestalt Principles
Logos look like they are just simple illustrations to represent a brand in advertising. Every business has a logo and even many government departments.
However, logos are actually essential to the organization and can play a vital role in creating a favorable impression in potential customers.
To examine the effectiveness of tourism logos, Rodriguez et al. (2013) collected 154 logos from the tourism websites of 116 countries. Two graduate students with backgrounds in visual communication then rated each logo based on six Gestalt principles: similarity, proximity, continuity, figure-ground, closure, and assimilation.
The logos were then rated by over 200 undergraduate students in terms of how well the logo represented its country and how much they would like to travel to that country.
“Logos high in Gestalt traits registered the highest intention to visit among the respondents … logos high in Gestalt attributes indeed influenced the ease with which people can recognize the nations the logos stand for” (pp. 101-102).
3. A New Graph Design
Gestalt principles also play a role in the interpretation of graphs and charts. Unfortunately, many students “have difficulty interpreting the line graphs accurately… obtain only a superficial and incomplete understanding of the relationships between the variables” (Ali & Peebles, 2013, p. 186).
The authors decided to apply the Gestalt principle of similarity to create a unique “color-matching” type of graph format. In this new format, the color of the legend and each X-variable match. In addition, the color of the plot line end points match the X-axis labels.
Forty undergraduate psychology students were presented with numerous graphs either in the typical format or in the new format.
Results “revealed that the color-match graphs resulted in more correctly interpreted trials than did the normal line graphs…by bringing the Gestalt principle of similarity into effect” (p. 199).
Leading the authors to conclude: “Knowledge of the various effects of Gestalt principles on perception and subsequent interpretation can inform graph design…” (p. 200).
The Case Studies on the Gestalt principle of similarity can be applied to academics in several ways.
1. Making a Slide Deck
When making a slide deck for a class presentation, use color-matching to highlight key points throughout the presentation. For example, key take-aways at each section could be presented in the same color that is either a shade or two brighter than the other text, or in a completely different color.
2. Creating Concept Maps
When writing a paper that contains a thorough literature review, keep in mind that trying to digest all of that text can get tedious for the reader. So, provide a knowledge/concept map that shows how the different research papers are related. Put specific studies that fall into the same subject domain in the same color.
3. Organizing Notes by Color
When studying for an exam, make a new version of your notes that incorporates similarity of color. For example, while most of the re-written notes could be in black text, the most important points from each lecture could be in a different color, such as red or bright blue.
This can also be applied to your notes on chapters (you do take notes while reading a chapter, don’t you?).
The Gestalt principle of similarity tells us that individual elements that look the same will be perceived as belonging to the same category.
Similarity can be in the form of using the same color or shape. This immediately creates the impression of being related.
For example, parts of a menu that are in the same font and color will be easily discernable from other information.
When trying to understand complex academic subjects, it can help to organize related information by presenting it in the same color scheme. This applies to making knowledge/concept maps, organizing lecture notes, or making a slide deck for a class presentation.
Ali, N., & Peebles, D. (2013). The effect of Gestalt laws of perceptual organization on the comprehension of three-variable bar and line graphs. Human Factors, 55(1), 183–203. https://doi.org/10.1177/0018720812452592
Görgen, İ. (2008). The effects of differences in the configurations of knowledge
maps (k-map). Eurasian Journal of Educational Research, 33, 157-176.
Koffka, K. (1935). Principles of Gestalt psychology. London, England: Lund Humphries.
Köhler, W. (1938). Physical Gestalten. In W. D. Ellis (Ed.), A source book
of Gestalt psychology (pp. 17–54). London, England: Routledge &
Kegan Paul. (Original work published 1920)
Rodriguez, L., Asoro, R. L., Lee, S., & Sar, S. (2013). Gestalt principles in destination logos and their influence on people’s recognition and intention to visit a country. Online Journal of Communication and Media Technologies, 3(1), 91.
Wagemans, J., Elder, J. H., Kubovy, M., Palmer, S. E., Peterson, M. A., Singh, M., & von der Heydt, R. (2012). A century of Gestalt psychology in visual perception: I. Perceptual grouping and figure–ground organization. Psychological Bulletin, 138(6), 1172–1217. https://doi.org/10.1037/a0029333
Wallace, D. S., West, S. W. C., Ware, A., & Dansereau, D. F. (1998). The effect of knowledge maps that incorporate gestalt principles on learning. The Journal of Experimental Education, 67(1), 5-16.
Wertheimer, M. (1938). Gestalt theory. In W. D. Ellis (Ed.), A source book of Gestalt psychology (1-11). New York, NY: Harcourt.
Dr. Chris Drew is the founder of the Helpful Professor. He holds a PhD in education and has published over 20 articles in scholarly journals. He is the former editor of the Journal of Learning Development in Higher Education. [Image Descriptor: Photo of Chris]