Why automaticity (aka 'fluency') is important in learning to read (opinion)
Driving an automobile effortlessly through traffic is one example of automaticity. However, it was not always so easy. Recall your first ventures behind the wheel, when considerable attentional energy was consciously applied to mechanical aspects of driving such as avoiding accidents and shifting gears. For the beginning driver, so much attention is focused on the mechanical aspects of driving that holding a conversation with a passenger while driving is impossible. But with practice, the mechanical aspects of driving become less demanding, and the skilled driver can simultaneously listen to the radio, hold a conversation, and appreciate the scenery. Skills practiced and learned to the point where they are considered ‘automatic’ demand less cognitive and attentional energy; thus the person with expertise is capable of performing multiple complex tasks at the same time.
Another example of automaticity may be found in a high school student reading a social studies text. If the student is a skilled reader, multiple tasks are being performed at the same time, such as decoding the words, comprehending the information, relating the information to prior knowledge of the subject matter, making inferences, and evaluating the information's usefulness to a report he or she is writing. These examples highlight one benefit of developing a skill to an automatic level—namely, the ability to perform multiple tasks simultaneously. This ‘multi-task functioning’ is possible due to the reduced attentional demands needed to perform the automatized task, thus freeing up attentional energy for other functions. The ability to perform several complex tasks at the same time—whereas at the beginning of training one could only perform one task—is an important characteristic of expertise. Dual-task performance in reading, such as the ability to decode and comprehend simultaneously, is an important indicator that the decoding is automatic.
Samuels, S. J., & Flor, R.F. (1997). The Importance of Automaticity for Developing Expertise in Reading. Reading & Writing Quarterly 13 (2) p. 107 — 121.