A simple and sensitive method to measure timing accuracy.
Timing accuracy in presenting experimental stimuli (visual information on a PC or on a TV) and responding (keyboard presses and mouse signals) is of importance in several experimental paradigms. In this article, a simple system for measuring timing accuracy is described. The system uses two PCs (at least Pentium II, 200 MHz), a photocell, and an amplifier. No additional boards and timing hardware are needed. The first PC, a SlavePC, monitors the keyboard presses or mouse signals from the PC under test and uses a photocell that is placed in front of the screen to detect the appearance of visual stimuli on the display. The software consists of a small program running on the SlavePC. The SlavePC is connected through a serial line with a second PC. This MasterPC controls the SlavePC through an ActiveX control, which is used in a Visual Basic program. The accuracy of our system was investigated by using a similar setup of a SlavePC and a MasterPC to generate pulses and by using a pulse generator card. These tests revealed that our system has a 0.01-msec accuracy. As an illustration, the reaction time accuracy of INQUISIT for a few applications was tested using our system. It was found that in those applications that we investigated, INQUISIT measures reaction times from keyboard presses with millisecond accuracy.
De Clercq
Armand
A
Department of Applied Mathematics and Computer Science, Ghent University, Ghent, Belgium. armand.declercq@rug.ac.be
Crombez
Geert
G
Buysse
Ann
A
Roeyers
Herbert
H
D006801:Humans; D008838:Microcomputers; D011597:Psychomotor Performance; D011930:Reaction Time; D013998:Time Perception / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*