Behavior Research Methods, Instruments, & Computers

, Volume 35, Issue 1, pp 109–115

A simple and sensitive method to measure timing accuracy

  • Armand De Clercq
  • Geert Crombez
  • Ann Buysse
  • Herbert Roeyers
Article

Abstract

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.

Supplementary material

DeClercq-BRM-2003 link.txt (0 kb)
Supplementary material, approximately 340 KB.

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Copyright information

© Psychonomic Society, Inc. 2003

Authors and Affiliations

  • Armand De Clercq
    • 1
  • Geert Crombez
    • 1
  • Ann Buysse
    • 1
  • Herbert Roeyers
    • 1
  1. 1.Department of Applied Mathematics and Computer ScienceGhent UniversityGhentBelgium

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