The Delboeuf illusion is an optical illusion of relative size perception: In the best-known version of the illusion, two discs of identical size have been placed near to each other and one is surrounded by a ring; the surrounded disc then appears larger than the non-surrounded disc if the ring is close, while appearing smaller than the non-surrounded disc if the ring is distant. A 2005 study suggests it is caused by the same visual processes that cause the Ebbinghaus illusion.^[1]

Eponym[edit]

To minimize the Delboeuf illusion, serve food on plates with a contrasting color to the food you plan to serve at a meal. The authors also found the background colors, such as the color of the table, the tablecloth, or placemats, also help in eating smaller portions. A tablecloth with a low contrast to the dishes can minimize the effect of the. Nov 11, 2011 food, the dinnerware, and the tablecloth influences the Delboeuf illusion. This research is organized as follows. First, the Delboeuf illusion is introduced as a potential explanation for the link between the size of dinnerware and serving behavior and consumption. Second, four lab studies examine the opposing.

The Delboeuf illusion appears within real-world decisional settings as well, such that adult humans overestimate food portions (e.g., amounts of cereal) presented in small dishware (assimilation. Our main contention is that the Delboeuf illusion biases consumers’ ability to accurately determine how much food they need to serve to reach the target serving size they would otherwise typically serve and consume. Basically, when our plate is large, we sense a large gap between the edges of the serving size and the plate. The Delboeuf illusion (often in connection with the Ebbinghaus illusion) has been used with great frequency in testing animal perception, since the ability to discern size seems highly relevant for many aspects of survival, particularly regarding food. The perception of the Delboeuf illusion differs greatly depending on the species.

The illusion was named for the Belgian philosopher, mathematician, experimental psychologist, hypnotist, and psychophysicist Joseph Remi Leopold Delboeuf (1831–1896), who created it in 1865.^[2]

Factors[edit]

According to Girgus and Coren (1982) the Delboeuf illusion uses both assimilation and contrast as elements in its perception distortion.^[3] Assimilation is the predominant factor in the disc in the smaller outer ring (the example on the right in the image above). Girgus and Coren mentioned that this inner disc “tends to be overestimated” when compared to a regular disc without the additional concentric circle.^[3] As the two circles are so close, they are perceived as a pair and the inner circle is overestimated.

The circle on the right however, will often appear smaller when compared to a simple circle of the same size. This is attributed to the contrast effect. The distance between the circles causes them to be perceived as separate and contrasting. The larger-circumference ring dwarfs the smaller central disc and causes it to be perceived as smaller.^[3]

After a few minutes of looking at this illusion, the illusory effects diminish for human subjects.^[3]

Studies regarding variations of the Delboeuf illusion found that when the outer circle is incomplete, the illusion is not as potent. When an additional circle was added surrounding the original two, the effect of the illusion was increased.^[4]

Dieting and food perception[edit]

In 2012, Ittersum and Wansink published a study that hinted to the Delboeuf illusion as a factor in increased food servings. The study tested three different bowl diameters and measured how individuals served themselves differently depending on the bowl's diameter. The results showed that consumers poured 9.9% more soup in larger bowls, and 8.2% less in smaller bowls, as compared to the control bowls. It was mentioned that this reaction could be driven by the Delboeuf illusion.^[5]

This illusion in connection to food however appears to be nuanced: Tzvi & Zitron-Emnual (2018) highlighted how effects of the Delboeuf illusion, when related to food items, is less potent when the participants are experiencing mild hunger. These researchers suggest that these findings are potential grounds for mitigating the use of the Delboeuf illusion as a dieting aid.^[6]

Use in animal cognition[edit]

The Delboeuf illusion (often in connection with the Ebbinghaus illusion) has been used with great frequency in testing animal perception, since the ability to discern size seems highly relevant for many aspects of survival, particularly regarding food. The perception of the Delboeuf illusion differs greatly depending on the species.

Primates[edit]

Parrish & Beran (2014) found that chimpanzees would regularly select food platters that contained more food. Further testing showed that when chimpanzees were offered food on small and large plates, as they often picked the food on the smaller plate, even when the amounts were the same. This was discussed as a sign of the chimpanzee’s susceptibility to the Delboeuf illusion.^[7]

A later study showed that capuchin and rhesus monkeys however, were unaffected by the illusion when asked to discriminate between the two circles. In contrast, when the illusion was later presented to the monkeys as part of an absolute classification task (deciding if the circles were 'big' or 'small'), both species reacted to the illusion and made selections that were much like the selections made by humans and chimpanzees.^[8]

An attempt to run tests of portion discrimination in connection to the Delboeuf illusion on ring-tailed lemurs was unsuccessful; the lemurs' meal selections were not increased by a statistically significant degree by larger food portions, unless one option was nearly 40% larger.^[9]

Dogs[edit]

Miletto-Petrazzini, Bisazza and Agrillo (2016) replicated the study conducted by Parrish and Beran (2014) but used dogs as the participants instead of chimpanzees. In this study, the dogs were allowed to select whichever food portion appeared larger as presented on larger and smaller plates. The response however was reversed from what humans usually exhibit: Dogs selected the meal presented on the larger plate most often. The authors went on to discuss how this may hint towards the dogs' reactions to the Delboeuf illusion as a matter of assimilated learning.^[10]

Fish[edit]

Fish have been repeatedly studied as well to understand if they perceive the Delboeuf illusion. Fish trained to select larger center circles for reward, responded to the illusion differently depending on the species of fish. A 2008 study of damselfish illustrated that damselfish responded to variations of the Delboeuf illusion in a similar ways to humans and dolphins,^[11] while guppies responded in reverse, selecting the circles with the larger annulus.^[12]bamboo sharks did not generally make selections significantly higher than chance during the testing, and only showed preference to larger diagrams in general.^[11]

Reptiles[edit]

Bearded dragons and red-footed tortoise were both studied to understand if these species can perceive the Delboeuf illusion. Bearded dragons showed action that suggests that they perceive the illusion in a way similar to humans. The tortoises however, showed no preference to larger portions (a similar problem found in the study of ring-tailed lemurs) and were thus not testable by the method that had been outlined by the test designers.^[13]

References[edit]

1. ^Roberts B, Harris MG, Yates TA (2005). 'The roles of inducer size and distance in the Ebbinghaus illusion (Titchener circles)'. Perception. 34 (7): 847–56. doi:10.1068/p5273. PMID16124270.
2. ^Delboeuf, Franz Joseph (1865). 'Note sur certaines illusions d'optique: Essai d'une théorie psychophysique de la maniere dont l'oeil apprécie les distances et les angles'. Bulletins de l'Académie Royale des Sciences, Lettres et Beaux-Arts de Belgique (in French). 19: 195–216.
3. ^ ^abcdGirgus, Joan S.; Coren, Stanley (1982-11-01). 'Assimilation and contrast illusions: Differences in plasticity'. Perception & Psychophysics. 32 (6): 555–561. doi:10.3758/BF03204210. ISSN1532-5962. PMID7167354.
4. ^Weintraub, Daniel J.; Schneck, Michael K. (1986-05-01). 'Fragments of Delboeuf and Ebbinghaus illusions: Contour / context explorations of misjudged circle size'. Perception & Psychophysics. 40 (3): 147–158. doi:10.3758/BF03203010. ISSN1532-5962. PMID3774497.
5. ^van Ittersum, Koert; Wansink, Brian (2012-08-01). 'Plate size and color suggestibility: The Delboeuf illusion's bias on serving and eating behavior'. Journal of Consumer Research. 39 (2): 215–228. doi:10.1086/662615. ISSN0093-5301.
6. ^Zitron-Emanuel, Noa; Ganel, Tzvi (1 September 2018). 'Food deprivation reduces the susceptibility to size-contrast illusions'. Appetite. 128: 138–144. doi:10.1016/j.appet.2018.06.006. ISSN1095-8304. PMID29885383.
7. ^Parrish, Audrey E.; Beran, Michael J. (2014-03-01). 'When less is more: like humans, chimpanzees (Pan troglodytes) misperceive food amounts based on plate size'. Animal Cognition. 17 (2): 427–434. doi:10.1007/s10071-013-0674-3. ISSN1435-9456. PMC3865074. PMID23949698.
8. ^Parrish, Audrey E.; Brosnan, Sarah F.; Beran, Michael J. (October 2015). 'Do you see what I see? A comparative investigation of the Delboeuf illusion in humans (Homo sapiens), rhesus monkeys (Macaca mulatta) and capuchin monkeys (Cebus apella)'. Journal of Experimental Psychology, Animal Learning and Cognition. 41 (4): 395–405. doi:10.1037/xan0000078. ISSN2329-8456. PMC4594174. PMID26322505.
9. ^'Preliminary study to investigate the Delboeuf illusion in ring-tailed lemurs (Lemur catta): Methodological challenges'. Animal Behavior and Cognition. Retrieved 2020-04-04.
10. ^Miletto Petrazzini, Maria Elena; Bisazza, Angelo; Agrillo, Christian (2017-05-01). 'Do domestic dogs (Canis lupus familiaris) perceive the Delboeuf illusion?'. Animal Cognition. 20 (3): 427–434. doi:10.1007/s10071-016-1066-2. hdl:11577/3222731. ISSN1435-9456. PMID27999956.
11. ^ ^abFuss, Theodora; Schluessel, Vera (2017-08-01). 'The Ebbinghaus illusion in the gray bamboo shark (Chiloscyllium griseum) in comparison to the teleost damselfish (Chromis chromis)'. Zoology. 123: 16–29. doi:10.1016/j.zool.2017.05.006. ISSN0944-2006. PMID28712674.
12. ^Lucon-Xiccato, Tyrone; Santacà, Maria; Miletto Petrazzini, Maria Elena; Agrillo, Christian; Dadda, Marco (2019-05-01). 'Guppies, Poecilia reticulata, perceive a reversed Delboeuf illusion'. Animal Cognition. 22 (3): 291–303. doi:10.1007/s10071-019-01237-6. ISSN1435-9456. PMID30848385.
13. ^Santacà, Maria Miletto; Petrazzini, Maria Elena; Agrillo, Christian; Wilkinson, Anna. 'Can reptiles perceive visual illusions? Delboeuf illusion in red-footed tortoise (Chelonoidis carbonaria) and bearded dragon (Pogona vitticeps)'. Journal of Comparative Psychology. 133 (4): 419–427. doi:10.1037/com0000176. Retrieved 2020-04-04.

Use the Delboeuf Illusion to influence elderly food consumption? If you are not familiar, the Delboeuf illusion is an optical illusion of relative size perception. The best-known image exemplifying this illusion is two circles of identical size placed near to each other. One is surrounded with another circle. The Delboeuf Illusion makes the one surrounded by a circle look larger than the other. It is not.

The Delboeuf Illusion can influence elderly food consumption because vision plays a huge role in our perception of food. It influences how much we eat. Vision even affects our perception of how we think the food tastes.

A while back there were reports that using red plates for Alzheimer’s patients helped the elderly eat more food. Getting Alzheimer’s patients to eat more is a common struggle and many people ran out and purchased red plates. There were even companies selling red dinnerware and cups, specifically targeting caregiver’s of Alzheimer’s patients. Red plates did work much of the time, however a newer study demonstrated some faults in the concept. The newer study explored the Delbouef Illusion’s Bias on Serving and Eating Behavior.

We are influenced by more than plate color.

The researchers of the, “Plate Size and Color Suggestibility” study, did confirm that red plates could cause increased consumption of food,but only if there was a significant contrast with the food on the plate. Thus red plates were not always the best option to help the elderly to eat more. The study also discovered methods that will help people eat less. Basically their study revealed that the following methods would encourage people who struggle with vision issues or loss of interest in food to eat more:

1. Use larger dinnerware to serve meals. Larger plates makes it seem like there is less food on the plate.
2. Use dinnerware that contrasts greatly in color to the food (e.g. white food on red pates and red food on white plates)
3. Use dinnerware that closely matches the color of the tablecloth.

Because of the Delbouf Illusion, how much one consumes is highly influenced not only by plate color, but also by plate size and even the background (tablecloth) the plate is placed upon.

Influence elderly food consumption by encouraging the elderly to eat more.

Getting the elderly to eat more is often an issue with Alzheimer’s patients and with the elderly who have health or vision issues. According to the American Family Physician organization, approximately one person in three has some form of vision-reducing eye disease by the age of 65. The most common causes of vision loss among the elderly are age-related macular degeneration, glaucoma, cataract and diabetic retinopathy. Vision issues can significantly reduce interest in food. If you struggle to see the food on the plate, you are less likely to eat it. Below are three methods to increase food consumption:

1. Purchase a selection of both light and dark dinnerware and tablecloths that match the color of the dinnerware as closely as possible. By having the tablecloth and dinnerware match, it helps create the impression that the plate is larger by reducing its edges.
2. Choose oversized dinnerware. Often square plates are larger than round plates, but all dinnerware varies in size. Dinner plates that are 14” in diameter are as available as 11” diameter plates. It is even possible to find 16” dinner plates. Also look for dinnerware that has as small a rim as possible. This will maximize the plating area.
3. Coordinate your dinnerware to contrast with the food you are serving. This will make it as visible and appetizing as possible. Serve cottage cheese, Alfredo, and mashed potatoes on dark dinnerware. Serve salads, chili, and tomato soup using light or white dinnerware.

Employing these methods utilizes the Delboef Illusion to influence elderly food consumption. The illusion convinces the person consuming the meal that there is less food in front of them. Because the plate is larger and it fades into the same color tablecloth, the food portions will appear to be a smaller portion. The contrast between the food and dinnerware increases the visual appeal of the food being served, and it helps delineate the food from the plate. Whether your parent is a finicky eater or has vision difficulties, they will eat more of the food you serve them.

Delboeuf Illusion Definition

Influence elderly food consumption by encouraging the elderly to eat less.

Often times the elderly find themselves in a sedentary lifestyle due to surgery or health issues. Others may have struggled with being overweight all their lives and are now faced with losing weight. Changing a lifetime of eating habits is difficult, but you can use the Delboef Illusion to help the elderly eat less. Below are three methods to decrease food consumption

Delboeuf Illusion And Food Chain

1. Purchase a selection of both light and dark dinnerware and the tablecloths that match in color as much as possible. By having the tablecloth and dinnerware match, it helps to create the impression that the plate is larger by reducing its edges.
2. Choose undersized dinnerware that is 10 inch or 9 inch plates if you can. Select dinnerware with e a small rim over a large rimmed plate so the elder feels they have all plate “real estate” available to them.
3. Coordinate your dinnerware to contrast with the food you are serving. This will make it as visible and appetizing as possible. Serve cottage cheese, Alfredo, and mashed potatoes on dark dinnerware. Serve salads, chili, and tomato soup using light or white dinnerware.

Employing these methods utilizes the Delboef Illusion to influence elderly food consumption. The illusion convinces the person consuming the meal that there is a full plate of food in front of them. The smaller plate will make servings appear larger and the similarity between the plate and the tablecloth will make the plate look larger. The contrast between the food and dinnerware increases the visual appeal of the food being served, and it helps delineate the food from the plate. Using this method will allow you to serve a person much less food but help them feel as if they have had a full meal. .

Delboeuf Illusion Food

Other aspects of the study worth noting.

The study also showed there is a difference between being served and self-serving food. The researchers discovered, we have a strong tendency to over serve ourselves if we place food onto a plate that has little contrast to the food. It may seem a little confusing, but it all comes down to how visible the food is on a plate. In the process of self-serving you will put more greens onto a green plate than you will a white plate. And you put more Alfredo on a white plate than a red plate. A significant contrast between food and plate actually influences you to make the serving smaller. Same with a large versus a small plate. A large plate influences you to put more food on it than a small plate does. So when you are plating food for someone else, you’ll need to keep this in mind.

Keeping plate color and size, food contrast, and who is doing the serving clearly in mind before plating a meal can help you achieve concrete goals of increasing or decreasing food consumption. You can help the elderly eat more or less using the delboeuf illusion at each and every meal. You can even use it on yourself.

To read the study in its entirety, you can find it here:

Plate Size and Color Suggestibility: The Delboeuf Illusion’s Bias on Serving and Eating Behavior ,Koert Van Ittersum and Brian Wansink, Journal of Consumer Research, Vol. 39, No. 2 (August 2012) (pp. 215-228), Electronically published November 11, 2011

Check out Other Articles on Our Site