The span of vision in reading and the legibility of letters
Journal of Educational Psychology
Communicated by Prof. W. B. PILLSBURY SUMMARY 1. The span of distinct vision for letters in 10 point type at a distance of 35 cm. from the eyes was found to be from 20 mm. to 22 mm. on either side of the fixation point. It has been shown by other investigators that the distance between fixations varies from 10 mm. to 20 mm. It would seem, therefore, that in ordinary reading all the letters read must come within the field of distinct vision, and that probably the fields of distinct vision
... in successive fixations. 2. Broad letters were the most legible. Narrow letters and some of the tall ones were found near the end of the series. Confusion between letters was apt to take a definite direction, e. g., f was judged t more often than t was judged f. 3. The results of these experiments are in accord with Dor's tests of the acuity of peripheral vision by means of dots. The problem of this experiment was the determination of the width of the field of distinct vision for each letter of the alphabet. The first part of the problem, the width of the field, was suggested by the work done by other investigators on the fixation pauses in reading. The second phase of the problem, the relative legibility of the letters of the alphabet, was a natural outgrowth of the first. It was thought that it might be interesting to determine, if possible, whether some of the letters might not be worthy of some change in order to facilitate reading.