Note 48 — Chapter III

Professor Preyer has ascertained experimentally the number of objects (such as shot-corns, pins, or dots on a piece of paper), which admit of being simultaneously estimated with accuracy. (Sitzungs berichten der Gesellschaft für Medicin und Naturwissenshaft, 29 Juli, 1881.) The number admits of being largely increased by practice, until, with an exposure to view of one second’s duration, the estimate admits of being correctly made up to between twenty and thirty objects. (See also Mental Evolution in Animals, p. 138.)