Ideas which have been developed simultaneously or in immediate succession in the same mind mutually reproduce each other, and do this with greater ease in the direction of the original succession and with a certainty proportional to the frequency with which they were together.

While the specifics on how these mental abilities were measured have been lost the successes achieved by the commission laid the groundwork for future intelligence testing. After eliminating the meaning-laden syllables Ebbinghaus ended up with 2300 resultant syllables. At the age of 17 (1867) he began attending the University of Bonn where he had planned to study history and philology.

Hermann Ebbinghaus (January 24 1850 — February 26 1909) was a German psychologist who pioneered the experimental study of memory and is known for his discovery of the forgetting curve and the spacing effect. He was also the first person to describe the learning curve.