Visual Attention Span (VAS)

Experienced readers rely upon processing words by sight. If a child has a reduced ability to process words as a whole then they are forced to sound words out, which is their only way to make sense out of the print on the page.

Many children struggle with whole word processing because they have limited visual attention spans, which refers to the amount or bits (eg. letters) of information which can be ‘grabbed’ or captured off the page with each fixation. The average span of recognition for an experienced reader is 4-6 letter positions. We are able to identify the shape of letters 10-12 letter positions away from fixation, but not their identity. We are able to identify the length of a string of letters 13-14 letter positions away from fixation, but cannot decipher the shape or the identity of the most distal letters. ie. those furthest away.

When reading the more letters that we can capture with each fixation, the longer the words we can read and the larger our sight word vocabulary. Whilst experienced readers have a visual attention span of 4 to 6 letters many young children are only able to capture one letter at a time in their working memory, which is generally going to be a letter at the beginning of the word. Therefore the word ‘magnet’ would be processed as ‘m_____’. Their limited attention span makes the child insensitive to all the other letters in the word, it’s as if they are reading down a cardboard tube, or even a straw. These same children will also be insensitive to word length, as such the child may misguess the word as ‘measles’, ‘mistletoe’, ‘mother’ etc. In fact there are over 400 words that would fit this visual pattern. Whole word processing is therefore inevitably inaccurate in these children; nor can they rely on context because the same problems of word recognition apply to all words in the sentence.

As a result the child may become a word guesser. To make matters worse if the child has poor ‘sounding out’ (phonemic processing) skills then they will be completely locked out of the reading process.

A child with a visual attention span of 2 will usually select the two end letters ‘m____t’ when reading. However there are still over 40 words (meat, mist, moat etc) that will fit this pattern, and so word guessing is still not reliable.

When a child can process 3 letters, m_g__t, there are only a few words that form a match in memory (maggot, magnet, midget etc). Therefore their predictive guessing is likely to be more accurate. As a result in order for a child to be a sight word reader they must be able to capture three ‘bits’ of information consistently.

Visual attention span improves with age and will improve with reading experience yet many children starting school lack the capacity to accurately capture sufficient visual information to support sight word reading. As such they are locked out of the normal sight word reading processes. Studies have demonstrated that visual attention span correlates significantly with reading readiness in kindergarten[i] and with reading in Grades 1 through 5[ii].

A visual attention deficiency can create a detrimental guessing dependency which can be difficult to break even once the child’s visual attention spans have improved. For example a child with a visual attention span of 2 who is only able to process the end letters of a word will often guess the mid-word letters and may become insensitive to their sequence.

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