Line Art Drawing
Ever wonder why we recognize a face from a line drawing?
Consider a line drawing or cartoon as a portrait of a person. Think about how it works. People don't have lines on their faces normally. In some cases there are edges where a foreground object is seen as distinct from a background. Are these edges really lines or something that our mind creates and tells us are there to help us make sense of what we are seeing?
As I experiment with drawing lines to depict a real person, I use a photograph. The photo has a great many likely boundaries and other lines to choose from. Wrinkles, smile lines, cheek folds, shadow lines etc.
What I have found is that the lines that count are the ones that suggest physical structural boundaries or limits. They are not always clearly defined edges but sometimes just an indication of a change in surface curvature.
For example, viewed straight on in a photo, a face may not show any edges at all along the mid line of the nose. However, it usually looks right if the area of a nose that is highly inclined to the viewer is defined by a nose line even if none appears as an edge in the photograph. What I believe is in a cartoon a line is accepted by the mind as a substitute for a message from the lower brain telling it there is a boundary or change in depth here.
Besides boundary pre-processing the lower mind also must work to recoginize specific facial features and send that information up to the surface visual mind.
Not sure if that is true? Look at the face on the right.
OK so it is upside down.
So what? (Maybe she is a little unhappy about it.)
Do you see anything wrong with the image? Study it a little bit and then Scroll Down
WOW! Did you quite expect this? Did you notice that her eyes were flipped too? It wasn't that she was unhappy, She looks like one of the actors from an episode of the "Twilight Zone"
So what happened here? With the picture upside down her eyes and mouth appeared in their normal orientation and your visual sub brain passed on the information that there were eyes and mouth in a face. Your higher visual brain may have noticed the expression clues about happy or sad and corrected for the orientation but it probably accepted the interpretation of the lower visual brain for the features. With the Picture right side up but the features upside down, your visual sub brain screams WRONG WRONG and your upper brain takes notice.
I would like to say I discovered this effect but I saw something like this demonstration in a science news magazine a few decades ago. Unfortunately I can't remember the title of the article and it may not be in Google anyway. Maybe a reader can help me give proper credit to the discoverer.
[footnote: Trying my hand at Google I found a few examples of this effect online. They seem to call it an "illusion" for lack of a better description. Someone refered to the original scheibe-illusion Professor Scheibe's altered photo was used for it. I was able to locate Prof Scheibe's email address and he was kind enough to tell me that he did not originate the illusion. He claims a student did it as a joke. Professor Scheibe said a similar illusion using Margaret Thacher's photo predated the one using his example and it was called the "Thacher Illusion". The example I remember, however, was of of another lady.]
Speaking of credit, I need to try and undo the damage I may have done in mangling the image of the lovely lady above. Her name is Carol Gault, and when I took her photo she was rushing to organize a booster meeting to help her win a seat on the Paducah KY City Commission. I am glad to say she was successful. (Congratulations Carol.)
For many years Carol has been a booster for downtown Paducah redevelopment working with the Main Street organization and has had a real positive impact. Paducah is lucky she was willing to take on the responsibilities of the City Commission.