The apparatus consists of a Random Number Generator (RNG) connected to a minicomputer. The RNG produces pulses randomly on two channels. The pulse rate can be set by the computer. The behaviour of the Random Number Generator is fed back to a display in the form of a line which starts on the top of the screen and develops downwards in time with the horizontal coordinate being determined by the cumulative difference in bits of both channels.

see fig.1 in EJP 1-1 pg.5

(for a demo of the display click on the figure)

The display is updated after each interval. Number of intervals and duration thereof are experimental parameters.


The goal of a subject is to influence the behaviour of the RNG in such a way that the line on the display develops into the target direction. Each of the 14 subjects participates in a total of 28 experimental runs. Fourteen of those have a targetdirection 'left' and 14 have a targetdirection 'right'. During the last 8 runs the RNG is switched off and pulses are used that have been recorded earlier but were not observed until they were used in these so-called prerecorded runs.

Run-durations vary depending on clock rate, number of intervals and interval duration, between 3 and 12 seconds. The subject initiates a run by pressing a button. For a detailed description of the design and the experimental parameters click here.