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Illusion Chasers

Illusion Chasers


Illusions, Delusions, and Everyday Deceptions
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‘Tis the season to be flossing: beware of dentistry illusions

The views expressed are those of the author and are not necessarily those of Scientific American.


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The surrounded circle looks larger than the isolated circle, even though both black circles are identical.

http://commons.wikimedia.org/wiki/File:Dentist_extracting_tooth..JPG

If you’re a bit lax with your post-holiday  brushing, this little-known illusion may give you the incentive you need to keep those candy canes in check, or at least brush and floss afterwards. Vision scientist Robert O’Shea and his colleagues published a recent study in PLoS One showing that dentists can fall prey to a visual illusion of size and make larger holes in teeth than needed.

 

 

 

http://commons.wikimedia.org/wiki/File:First_visit_to_the_dentist.jpg

The illusion fooling the dentists is a variant of a classical perceptual phenomenon known as the Delboeuf illusion, named after its creator, the Belgian natural philosopher, experimentalist, mathematician and hypnotist Joseph Remi Leopold Delboeuf.

 

 

 

 

 

 

 

http://commons.wikimedia.org/wiki/File:Dentist%27s_sign,_Hillsborough_-_geograph.org.uk_-_1591235.jpg

The scientists supplied 8 specialist dentists and endodontists, who served as experimental subjects, with a large pool of extracted teeth. The teeth contained holes, and the task of the dentists was to cut cavities in preparation for filling. Unknown to the dentists, each tooth presented a more or less powerful version of the Delboeuf illusion, making the holes appear smaller than their actual size. The results showed that the smaller the holes looked, the larger the cavities that the dentists made for later filling. The researchers recommend that dentists and other health practitioners receive training in “illusion awareness” (my words, not theirs), so that they may counteract these and related perceptual effects.

 

READ ABOUT OTHER SIZE ILLUSIONS HERE>>>

Susana Martinez-Conde About the Author: Susana Martinez-Conde and Stephen L. Macknik are laboratory directors at the Barrow Neurological Institute in Phoenix. Follow on Twitter @illusionchasers.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. RossRubino 5:22 pm 12/28/2013

    All great tips about the dental illusions out there.
    ______________
    Ross Rubino
    http://rubinodentistry.com/

    Link to this

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