Visual Crowding and Visual Overload PDF Print E-mail

"If there were only 10 problems on a page, I could do them all. But when there are 40 on a page, I can't do any of them." - 10 year old student

Visual overload and visual crowding are common problems in every school classroom or company work group, but the mistakes and errors that result from them are rarely recognized or traced back to their true source. It is a paradox - the more you see, the less you see, but it all makes sense if one recognizes that a child or an adult's visual working memory deskspace can become easily overloaded.

For visual scientists, visual crowding is a specific term that refers to a greater difficulty in seeing when other visual objects are present. When we look at a complex scene, for instance the picture above, it is impossible to take in all the other visual details. It's what causes some people to overload when they go to large gatherings like music concerts, Disneyland in the summertime, or a crowded Home Depot, but also children in crowded classroom, all-school assembly, writing on a scantron, or completing Mad Math Minutes.

Signs of Visual Overload

- Longer processing time, slow reading, and incomplete work on crowded worksheets

- Tantrums, irritability, and overload behaviors in crowded environments

- 'Careless' mistakes and unintentionally skipped problems on worksheets and tests

- Missed words or endings while reading, need to re-read words

Interestingly, a recent report on Visual crowding, reading, and dyslexia found that a visual crowding effect significantly contributed to slowness in word reading, and dyslexics as a group found that increased spacing between letters improved readability.

The critical spacing threshold for readability was significantly higher for dyslexics as a group compared to non-dyslexic controls, so it became easier to identify a letter away from the center if the spacing between characters were greater.

Take-home points:

- Critical print size is larger for dyslexics than controls

- Critical spacing between characters is larger for dyslexics than controls

- Reading rate improves with print size to a critical point

- Explains why many dyslexics with excellent verbal funds of knowledge still have trouble reading long words

Classroom and Test Accommodations In the classroom, more attention should be paid to print size and spacing in daily classroom (worksheets, handouts) and testing materials (as many as 1 in 5 students are dyslexic), and print size and spacing should be considered when purchasing books for students.

Large print books and reader glasses may help some students, whereas font differences (serifs like Times New Roman or hand-written fonts like Papyrus or Comic Sans often preferred) may be more important for others.

For students with narrow visual spans (see only few letters at a time), serifs or handwritten fonts may dramatically lessen the work of reading - with serifs or personalized font shapes - it is easier to perceive the overall shape of words, so that even if a reader only sees the first and last letters and general shape of the word, they can make an educated guess about what that word might be even though they are unable to see all the letters.

Many of you are probably aware of this meme from the Internet: "Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a toatl mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe." Matt Davis has written more about the science and history of the discovery of this effect here.

Eide Neurolearning Blog: Blessing and burdens of vivid visual thinkers

Eide Neurolearning Blog: Video game training increases visual span