Subitizing, Dynamic Vision, Saccade and Fixation Control and Their Role In Reading

Reading is a complex task that involves various subfunctions of vision. These subfunctions enable us to understand and comprehend written language. There are four subfunctions of vision that play a crucial role in reading. The first one is subitizing and visual number counting. This subfunction allows us to quickly recognize and count the number of words on a page. The second subfunction is dynamic vision, which enables us to track moving objects (or track stable object while we are moving), such as words as we read them. The third subfunction is saccade control, which allows us to make rapid eye movements from one word to the next. The final subfunction is fixation control, which enables us to keep our gaze on a specific word while we read.

Visual processing must be very fast to keep these subfunctions in sync and construct a stable perception of the visual scene. For instance, when we read, our brain must process the words in the correct temporal order and do this quickly to make sense of the text.

Researchers have found that people who performed poorly with the four tasks in reading and arithmetic can improve through regular practice. In one study, children were given a modified version of a reading task to practice at home for three weeks. After the practice period, clear improvements were observed in most children. A similar positive effect was also seen in dyslexic children with regard to basic arithmetic skills.