Studied individual differences in telegraphic writing. A preliminary study was conducted, in which operators were cross-examined on aspects of psychological or physiological importance. On the basis of this, a study was undertaken on 60 Ss, who were asked to write a sentence requiring attention. There were constant differences required in the times for a given character. Further tests were made, and schools were requested to provide typical curves of improvement. Results reveal that there were distinct specialties in telegraphy. The rate of receiving varied greatly, and exceeded sending rate. Both external and subjective disturbances affected inexperienced operators. The best age to learn telegraphy was 18-30 yrs. The variations in the value of a character depended on its place in the sentence. Homotaxic variation was an inverse measure of skill, while the inflection variation increased with expertise. (PsycINFO Database Record (c) 2016 APA, all rights reserved)