Speed reading is a collection of reading methods which attempt to increase rates of reading without greatly reducing comprehension or retention. Methods include chunking and eliminating subvocalization. No absolute distinct "normal" and "speed-reading" types of reading exist in practice, since all readers use some of the techniques used in speed reading (such as identifying words without focusing on each letter, not sounding out all words, not sub-vocalizing some phrases, or spending less time on some phrases than others, and skimming small sections). Speed reading is characterized by an analysis of trade-offs between measures of speed and comprehension, recognizing that different types of reading call for different speed and comprehension rates, and that those rates may be improved with practice. The many available speed reading training programs include books, videos, software, and seminars.
Psychologists and educational specialists working on visual acuity used a tachistoscope to conclude[when?] that, with training, an average person could identify minute images flashed on the screen for only one five-hundredth of a second (2 ms). Though the images used were of airplanes, the results had implications for reading.
Using the same methodology, the U.S. Air Force soon discovered that they could flash four words simultaneously on the screen at rates of one five-hundredth of a second (2 ms) with full recognition by the reader. This early form[which?] of Rapid Serial Visual Presentation demonstrated that reading speeds could be increased from reading rates to skimming rates, and visual processing could also be improved. Researchers suggested that readers could be instructed in a variety of pacing techniques in an attempt to improve reading. Use of a tachistoscope during instruction could increase reading speeds from 200 to 400 words per minute. However, post-instruction timings showed that speed gains rapidly diminished.
Following the tachistoscope discoveries, the Harvard Business School produced the first film-aided course, designed to widen the reader’s field of focus in order to increase reading speed. Again, the focus was on visual processing as a means of improvement. Using machines to increase people's reading speeds was a trend of the 1940s. While it had been assumed that reading speed increases of 100% were possible and had been attained, lasting results had yet to be demonstrated.
It was not until the late 1950s that a portable, reliable and convenient device would be developed as a tool for increasing reading speed. The researcher was a school-teacher named Evelyn Wood. She was committed to understanding why some people were naturally faster at reading than others and was trying to force herself to read very quickly. It is told that while brushing off the pages of the book she had thrown down in despair, she discovered that the sweeping motion of her hand across the page caught the attention of her eyes, and helped them move more smoothly across the page. She then used the hand as a pacer, and called it the "Wood Method", which was renamed to Reading Dynamics in 1958. She coined the term "speed reading."
Also, some speed reading proponents have taught that certain groups of people are more gifted at speed reading than others (e.g., young children, dyslexics, or those with ADHD). Speed Reading 4 Kids (2003) and Damn the School System — Full Speed Ahead!