Key Release [30011]

This article applies to:
E-Prime 3.0
E-Prime 2.0
E-Prime 1.x

 
Detail

This sample illustrates how to collect reaction times for key releases, using the 'Collection Mode' property for the input device (set within the Experiment Object), and specifying a '-' (minus) within the '{key}' nomenclature to indicate a release.
 
Abstract
This experiment is a modification of BasicRT and can be used to measure key release times in response to a stimulus. A fixation is presented, and the participant must press and hold the SPACEBAR in order to initiate the trial. The stimulus is presented after a variable duration (500 or 1000 msec). When the X or Y stimulus appears, the participant is to release the SPACEBAR. Reaction time (i.e., release time) is measured from the onset of the 'Stimulus' object to the release of the SPACEBAR. A Debug statement is used at the end of the trial to indicate that the time between stimulus onset and release time are equal to the RT logged for the 'Stimulus' object.

To collect key releases, open the Experiment Object > 'Devices' tab > select the appropriate response device > click 'Edit'. The 'Collection Mode' field in the 'Device Properties' dialog allows the selection of the type of response to collect (i.e., presses, releases, both presses and releases). To specify a release, use a '-' before the key name within curly braces {}. For example, to specify a press of the SPACEBAR, indicate '{SPACE}'. To specify a release of the SPACEBAR, indicate '{-SPACE}'. Refer to the '{KEY} Nomenclature' topic in the online documentation for more information.

Limitations: This experiment does not implement a check to make sure the SPACEBAR is down prior to presenting the stimulus. That is, the SPACEBAR is used to advance from the 'Fixation' object to the 'Stimulus' object, but additional checks should be put in place to determine that the SPACEBAR is still pressed (has not been released) prior to presenting the stimulus.