As soon as the signal was given, I lifted with my right hand a little revolving wheel with a colour-disk and made it run and change its color, and all the time, while I kept the little instrument at the height of my head, I turned my eyes eagerly toward it. While this was going on, up to the closing signal, I took with my left hand, at first, a pencil from my vest-pocket and wrote something at the desk; then I took my watch out and laid it on the table; then I took a silver cigarette-box from my pocket, opened it, took a cigarette out of it, closed it with a loud click, and [p. 30] returned it to my pocket; and then came the ending signal.
With this study, Munsterberg did what in our times is known as The Monkey Business Illusion where some kids play with a basketball, a person dressed in a gorilla suit crosses behind them but the viewer does not notice because we have been told to keep an eye on the ball. The instruction to concentrate on part of the video produces inattentional blindness. Munsterberg was experimenting with that phenomenon.