Stripes, dark colours and fit: what vision science says
Horizontal stripes don’t widen you the way the old rule says. What experiments found, what depends on the body, and which tips are only habit.
By the Fitsemble team ·
“Horizontal stripes make you look wider” is in almost every style guide, university extension leaflets included.1 It is also one of the few style rules anyone has tested in a lab. It mostly failed. Here is what the experiments say about stripes, dark colours, fit and lines, and how sure each finding is.
The square that started it
In the 1860s the physicist Hermann von Helmholtz noticed that a square filled with horizontal stripes looks taller and narrower than the same square filled with vertical stripes. He went further: a dress with horizontal stripes, he wrote, should make its wearer look taller.2 Today’s rule says the reverse.
What the experiments found
Horizontal stripes Mixed results
York, 2011. Peter Thompson and Kyriaki Mikellidou put Helmholtz to the test. To look as wide as a vertically striped square, a horizontally striped one had to be made about 4.5% wider. To look as tall, the vertically striped one had to be made about 7% taller. The same held for striped 3-D cylinders and for photos of a mannequin in striped dresses. In short: horizontal stripes looked slightly slimmer and taller, not wider.2
Kyoto, 2013. Hiroshi Ashida’s team found a catch. The effect was strong on slim figures, weaker or even reversed on heavier ones, and people differed a lot in what they saw.3
Amsterdam, 2021. Antonis Koutsoumpis and colleagues used photos of a real woman and compared horizontal stripes with a plain dress, not with vertical stripes. The striped dress looked slimmer. So did a darker dress compared with a lighter one. Each effect was small to moderate, and together they were larger.4
Dark colours Tested
The same 2021 study found that darker clothes made the body look slimmer, and that the effect grew when the background was dark too.4 Against a pale wall, a black dress does less than you might hope; at an evening event it does more. It is one study with one model, so treat it as a nudge, not a law.
Fit matters more than pattern Tested
Hong Kong, 2006. Fan Liu, Jintu Fan and Lilian Lau photographed nine men in five sizes of the same white T-shirt and asked people to judge their body size. For slim men, a bigger T-shirt made them look bigger. For men with a BMI above 28, a T-shirt that was too tight or too loose made them look larger. The smallest-looking fit had about 2 to 3 cm of room at the chest.5
Lincoln, 2017. Amelia Cundall and Kun Guo tracked the eyes of 33 women looking at female bodies from UK size 6 to 18 in tight or loose clothes. Loose clothes pulled the eye away from the waist and hips towards the legs, and larger bodies in loose clothes were judged smaller and more attractive.6
Put together: clothes that skim the body, close but not clinging, do more than any stripe. “Loose” in these studies means relaxed, not a tent; the T-shirt study shows that too much room adds size as well.
- Too tightPulls across the chest and stomach.
- A little roomAbout 2 to 3 cm at the chest: the smallest-looking fit in the T-shirt study.
- OversizedAdds width of its own.
Lines, waists and colour blocking
Missouri and Florida State, 2017. Jessica Ridgway and colleagues scanned women’s bodies, built each woman an avatar with her own face, and dressed it in seven dresses with illusion prints: stripes and lines that radiate from the waist, all designed to read as an hourglass. The women said the dresses made them feel better about their shape. Rectangles were most taken with the waist-shaping designs. Spoon shapes liked designs that drew the eye up to the bust and shoulders. Hourglass women were least moved, since the dresses aimed at the shape they already had.7 Tested
The rest of the classic line advice has, as far as we could find, not been tested on bodies: a V-neck lengthens the neck; one colour from top to toe makes a long, unbroken line; a strong contrast between top and bottom cuts the body in two; long vertical seams slim.1 Stylist convention These tips are reasonable, since the eye does follow lines, but they are habit, not evidence.
Leg length and where a hem falls
In a study across 27 countries, 3,103 people rated drawings of men and women whose legs were shorter or longer than average. Very short and very long legs were rated less attractive; slightly longer than average was preferred everywhere.8 That is the reasoning behind tips such as a higher waistline, shoes close to your skin or trouser colour, and hems that stop at a narrow point of the leg. The preference is tested; the tips that follow from it are convention. Stylist convention
The checklist
| What people say | What experiments found | Verdict |
|---|---|---|
| “Horizontal stripes make you wider.” | On average they looked slightly slimmer and taller2,4, but less so, or the reverse, on heavier figures.3 | Mostly myth |
| “Vertical stripes slim.” | Vertically striped shapes looked wider and shorter than horizontally striped ones.2 | Myth |
| “Black is slimming.” | Darker clothes did look slimmer, more so on a dark background.4 | Holds, a little |
| “Tight clothes make you look slimmer.” | For larger bodies, too tight looked bigger.5 | Myth |
| “Baggy clothes hide your size.” | Skimming, relaxed clothes helped6; oversized ones made bodies look bigger.5 | Only if not oversized |
Sources
- Wright, S., revised by Lujan, N. (2013). Fashion feasibility. Guide C-312, New Mexico State University Cooperative Extension. nmsu.edu
- Thompson, P., & Mikellidou, K. (2011). Applying the Helmholtz illusion to fashion: Horizontal stripes won’t make you look fatter. i-Perception, 2(1), 69–76. doi.org
- Ashida, H., Kuraguchi, K., & Miyoshi, K. (2013). Helmholtz illusion makes you look fit only when you are already fit, but not for everyone. i-Perception, 4(5), 347–351. doi.org
- Koutsoumpis, A., Economou, E., & van der Burg, E. (2021). Helmholtz versus haute couture: How horizontal stripes and dark clothes make you look thinner. Perception, 50(9), 741–756. doi.org
- Liu, F., Fan, J., & Lau, L. (2006). Perceived body size affected by garment and Body Mass Index. Perceptual and Motor Skills, 103(1), 253–264. doi.org
- Cundall, A., & Guo, K. (2017). Women’s gaze behaviour in assessing female bodies: The effects of clothing, body size, own body composition and body satisfaction. Psychological Research, 81(1). doi.org
- Ridgway, J. L., Parsons, J., & Sohn, M. (2017). Creating a more ideal self through the use of clothing: An exploratory study of women’s perceptions of optical illusion garments. Clothing and Textiles Research Journal. doi.org
- Sorokowski, P., Szmajke, A., Sorokowska, A., et al. (2011). Attractiveness of leg length: Report from 27 nations. Journal of Cross-Cultural Psychology, 42(1), 131–139. doi.org