Study title
The ambiguous #Dress image illusion
Ref study 13059
Study language English
Contributing institutions
  • Internet Dress
  • colour perception
  • visual illusion
  • colour vision
Geographical space
Lausanne, French-speaking Switzerland
  • Switzerland
In 2015, an ambiguous picture of a Dress triggered popular and scientific interest as different people perceive it having widely different colours. To help understand this phenomenon, we performed two studies. First, few days after the Dress appeared on the Internet, we projected the Dress to 240 students on a large screen (Experiment 1). The distribution of different colour perceivers partially confirms previous reports with the majority reporting seeing the Dress in blue and black (B&B; 48%) or white and gold (W&G; 38%). The third group of blue and brown (B&Br; 7%) viewers also emerged, and is worth further consideration. In a second, laboratory study, 57 participants used a computerized colour picker to precisely match colours of small squares (a) and vertical strips (b) cut out of the Dress picture, and the original Dress picture (c) (Experiment 2). Results indicated that lightness and chroma values of matched colours changed from B&B to B&Br to W&G viewers in contextualized images (b, c) only. Irrespective of viewer type or context conditions, the hues of the matched colours were either blue-purple (light parts of the Dress) or orange-yellow (dark parts). Finally, colours matched by B&B viewers were the closest to the colours displayed on the ambiguous Dress picture as compared to other viewer types. Our research supports the notion that the Dress effect emerges from differences in perceived lightness and chroma, but not hue. This phenomenon only occurs when all aspects of the picture are integrated, highlighting the importance of contextual information within the ambiguous Dress image.
(see abstract)
Methods (description)
Experiment 1:
- A class room study
- The ambiguous Dress image projected to 240 students
- Questionnaire method to determine the perceived colours of the Dress and inter-individual factors that could explain the differences in perception

Experiment 2:
- A laboratory study
- Participants seated in front of computer screen in a dark room and presented the Dress in three context conditions (as small squares, as strips, and as the entire Dress)
- Participants used a computerised colour picker ( to match the colours they perceived on the parts and the whole Dress

Colour blindness and demographical information collected in both experiments.
Methods (instruments)
  • Psychological test
Replicated study No
Financed by
Ethical approval No
Study type
Data availability
Source (Updates) Web
Date created 23.01.2018
Date modified 23.05.2018
Start - End date 02.03.2015 - 01.03.2017