Shape language

Shape language is the practice of building characters, props and spaces from a small, consistent set of basic forms, usually round, rectangular and pointed, so that viewers learn what each form signals. Animation and character design have taught it for decades, and some environment designers use it to tell players where they can go and what is safe (waltdisney.org: What is Shape Language?; 80 Level: Defining Environment Language for Video Games).

This page treats shape language as a vocabulary you define and keep consistent, rather than a set of universal emotional laws. The research behind "round means friendly" exists, but it is much narrower than most art tutorials suggest.

#The classic vocabulary

Most shape-language teaching starts from three primitives. The table compares how a character-design handout and an environment designer describe them.

Both sources qualify these readings. The Walt Disney Family Museum handout calls these general guidelines and notes that round characters can be villains, because shapes can disguise a character's true purpose (waltdisney.org: What is Shape Language?). Schatz says round and pointed shapes are not always wrong; adjusting them is one option when a scene does not read clearly (80 Level: Defining Environment Language for Video Games).

#Where the idea comes from

#Character design and animation

Shape language is most at home in character design. Tom Bancroft, a former Disney supervising animator and character designer who worked on Beauty and the Beast, The Lion King and Mulan, lists "Shape Variety" as the first tip in his character-design course (Class Central: Character Design with Personality: 4 Core…). The Walt Disney Family Museum's handout teaches circles, squares and triangles as shorthand for personality: round for warmth, square for sturdiness, triangular for sharpness or menace (waltdisney.org: What is Shape Language?).

In a character, the body is the whole message, so a strong shape idea carries a lot of weight. Environments are different: they are big, viewed from many angles, and full of things that have to look like real objects.

#Environment art

Environment artists borrow the idea for two jobs.

1. Gameplay readability. Emilia Schatz, a lead game designer at Naughty Dog, describes building "a clear and consistent shape language" so players can read the world's affordances, for example where they can climb or take cover (80 Level: Defining Environment Language for Video Games).
2. Mood and story. Art director Eddie Bennun's Gnomon Workshop course covers "the importance of shape language and its crucial role in creating a narrative composition", developing an image "from big shapes and silhouettes to small storytelling details" (The Gnomon Workshop: Environmental Storytelling: Composition and…). This ties shape language to composition and environmental storytelling.

The two jobs overlap but are not the same. The first is a contract with the player ("rectangular ledges here are climbable"). The second is an emotional nudge ("this spiky castle feels hostile").

#The Level Design Book's objection

The most outspoken critique comes from The Level Design Book, a free online book about game level design. Its page on the subject is subtitled "Bullshit design theories that link abstract visual phenomena to universal human behavior" (The Level Design Book: Shape and color psychology).

Its argument has three parts:

1. Meaning isn't universal. "Shape and color are abstract phenomena that do not have universal meanings for everyone around the world" (The Level Design Book: Shape and color psychology).
2. Meaning is contextual. Horizontal lines are said to feel stable, "until we see a fast flowing river strewn with wreckage" (The Level Design Book: Shape and color psychology).
3. Games have their own psychology. "Pointy things are bad!" holds only "until you need to collect pointy-shaped crystals to craft a valuable item", and round shapes feel safe "until you add a dangerous enemy to your game that is round" (The Level Design Book: Shape and color psychology).

The book compares shape psychology to astrology: "It's fun to think about," but "don't try to elevate it to a science" (The Level Design Book: Shape and color psychology). It concludes that shape and colour psychology "doesn't address how players play games" (The Level Design Book: Shape and color psychology).

Read closely, this critique targets universal shape psychology (the claim that circles make everyone feel safe). It does not reject what Schatz describes: a team deliberately deciding that rectangular ledges mean "climbable" in their game and keeping that rule consistent (80 Level: Defining Environment Language for Video Games). The sceptics and the practitioners disagree less about practice than about where the meaning comes from.

#Research on shape and perception

Shape-language tutorials often quote two lines of research. Both are useful to know, together with their limits.

#Bouba and kiki: sounds matched to shapes

In his 1929 book Gestalt Psychology, the psychologist Wolfgang Köhler showed readers a rounded and a jagged figure and asked which was "takete" and which "maluma" (Wikipedia: Bouba/kiki effect). In 2001 Ramachandran and Hubbard revived the idea with new figures and the made-up words "bouba" and "kiki", as part of a paper on synaesthesia (Ramachandran & Hubbard 2001; Wikipedia: Bouba/kiki effect). They reported that about 95% of people call the curvy shape "bouba" (Wikipedia: Bouba/kiki effect); a popular account puts it at "up to 98 percent", testing American college students and Tamil speakers in India (Gizmodo: The bouba/kiki effect).

A large cross-cultural test by Ćwiek and colleagues analysed 917 participants speaking 25 languages with 10 writing systems (Ćwiek et al. 2022). Their estimated match rate, counting a match only when both words were paired congruently, was 72%. "Bouba" matched the round shape more reliably than "kiki" matched the spiky one, and some languages, such as Romanian at 36%, fell below chance descriptively. The authors expected exceptions and did not claim the effect is universal in an absolute sense (Ćwiek et al. 2022).

What it shows: when forced to pick between two made-up words, most people link soft-sounding words to round shapes and sharp-sounding words to spiky ones.

What it does not show: that a round building makes a player feel safe, or that a spiky one makes them afraid. The task is about sound, not emotion or architecture.

#Curves, angles and liking

Bar and Neta showed 14 adults pictures of everyday objects for 84 milliseconds and asked for a gut "like" or "dislike" (Bar & Neta 2006). Curved versions were liked 67.2% of the time, sharp-angled versions 50.6%. The authors proposed that sharp contours signal threat and create a negative bias (Bar & Neta 2006; nmr.mgh.harvard.edu: Humans prefer curved visual objects).

Read the caveats as carefully as the headline:

• The sample was small, and threat was inferred, not measured (Bar & Neta 2006).
• Only neutral objects were tested. The authors note that strongly emotional objects can override the effect, and that fashion and aesthetic values also shape preferences (Bar & Neta 2006).
• A later study by Leder, Tinio and Bar (2011), summarised by Susan Weinschenk, found the curve preference for positive or neutral objects but not negative ones such as razor blades or spiders (The Team W blog: Post #106 in the series 'The Next 100 Things…).

Carbon's study of car design goes further. Ratings of car exteriors from 1950 to 1999 showed curvature, and liking for it, falling from the 1950s to a low around 1970–1980 and rising again by the late 1990s (Carbon 2010). Carbon concludes that "any study aiming to find static and general principles of liking regarding curvature is confounded with Zeitgeist effects" (Carbon 2010).

#Summary of the research

• There is good evidence for small, average biases: curves are slightly preferred for neutral objects, and sound–shape matching is common across many languages (Bar & Neta 2006; Ćwiek et al. 2022).
• There is no evidence that specific shapes reliably produce specific emotions in a game environment.
• Context has a strong effect. Content, fashion and familiarity can override or reverse the bias (Bar & Neta 2006; Carbon 2010).

#Shape language as a project vocabulary

If meaning comes mostly from consistency, the task is to define the vocabulary and apply it the same way throughout the project.

1. Write a shape key. Three lines in your art bible: which shape family means "usable", which means "hostile", which means "neutral or background". Tie each to a gameplay rule or a story faction.
2. Apply it at the primary-form level. Shape language lives in big masses first, then secondary detail. See primary, secondary and tertiary forms. Small bevels will not rescue a building whose main mass says the opposite.
3. Protect the outline. Shape reads through the silhouette. Schatz warns that the more an outline is obscured, "the harder it is to recognize for what it is" (80 Level: Defining Environment Language for Video Games).
4. Use contrast, not purity. A rectangle reads as "the usable thing" when it is surrounded by something else. Compare with value and colour for environments, which work the same way.
5. Back it up with metrics. Shape tells the player what kind of thing they see; metrics make sure the thing behaves that way every time.
6. Playtest it. If testers walk past climbable objects, your vocabulary is not landing (PlaytestCloud blog: Playtesting and Navigation: Explaining the…).

#Further reading and watching