I've tried with "key release", but what I need to know is how long does the subject keep pressed the key, not the time he takes to react since the onset of the stimulus.
I am working at a reproduction task of time perception: subjects have to keep a key pressed the same duration they believe a previous sound lasted.
Can you help me? Thanks a lot!
Hi Luigi. I think you should be able to measure the key press time as you wish by using Key Release RTs. This method in DirectRT is actually designed for paradigms in which a participant is supposed to press and hold one key before a stimulus is presented, then release it and press another key as quickly as possible. However, I think you could simply ignore the RT for the second key press and focus only on the release RT. For example, you could have your participants press the space, then present a simple text stimulus that said "Press the space now". DirectRT would think that this was when they were supposed to release the space and press something else, and so it would start recording an RT. You could then use this release RT as your measure.
To have DirectRT measure a release time, you'll need to replace the standard "rt:" in your input file's [B]time [/B]field with "rtr:". I've included a simple single trial example of this. When this input file comes up, DirectRT will first display "Press space now" for 2 second, cuing your participant to begin holding space. Then, it will display "Hold the space bar for the duration you believe the previous sound played." DirectRT will check to see if any key is currently being held. It will then begin recording how long it takes the participant to release that key and write the result to the data file in a column labeled "Release". When the subject is done, they will press enter to move the experiment along (this will also record an RT, but you can ignore this in your analysis and simply use the release RT).
I hope this helps!
Hello! As a follow up to this thread, is it also possible to measure the key that was pressed (participants are allowed to choose) together with the duration of keypress?
Thank you!
Jessica
The key that was pressed should be noted in the output files. The Resp column shows the keycode from the input file of the key that was pressed and the Name column shows the actual name of that key.