Timing individuals in a group using a computer-generated code sequence

A method of timing individual subjects in any size group is described. Using a standard movie projector, a specially produced 16-mm film projects codes composed of three letters. Each code remains on the screen for 2/3 sec. Subjects are asked to record the code they see after completing each experimental task. Computer programs, written in BASIC, generate the 1,000 codes used in the film, edit the subject-recorded codes, and translate the codes into time measures. The code sequence on the film is designed: (1) to discourage subjects from attempting to calculate their own interval times, (2) to catch false codes and recording errors, and (3) to allow the experimenter who knows the structure of the codes to easily translate individual codes into time.