ABSTRACT
For slighdy over a hundred years now. scientists have attempted to measure the speed of man's thought processes. The first systematic effort can be credited to Donders, who introduced the subtractive technique in 1868, but the greatest advances have taken place within the last \0 years. During the last decade the subtractive technique has been successfully applied to a wide variety of tasks, including visual and memory search. mental arithmetic. mental imagery, and linguistic comprehension.
