Key Release RTs


…\DirectRT\samples\5- other features\06 key release rts

Sample Description

In some paradigms, the subject is required to hold a key down prior to their response. When the time comes to react, the subject releases this key and responds as quickly as possible by hitting another key. This sample demonstrates such a task and shows how you can record the amount of time it took for the subject to release the first key and how long it then took to hit the response key.

Try running the sample input file "keyrelease.csv." You will be asked to press down on the space bar whenever you see the words "get ready" appear. You will then see a 3x2 grid appear that corresponds to the 6 keys: insert, home, pageup, delete, end, and pagedown. An X will appear in one of these cells and your task is to release the space bar and hit the key that matches the location of the X as quickly as possible. You will then return your finger to the space bar for the next trial.

When you open up the data file for the "keyrelease.csv" file, you'll see a column called "Release"--this is the number of milliseconds it took you to release the space bar from the time the image first appeared. The RT column is the reaction time to hit the correct (or incorrect) key which also starts from the time the image appears.

So how do we accomplish this? Take a look at the "keyrelease.csv" input file. You'll see that the only thing unusual in here is that in the Time column, you have "RTR:" instead of "RT:" for your trials. This essentially stands for "ReactionTime with ReleaseTime".



The previous stimulus in each trial (i.e., ~get ready) is simply a text prompt so that subjects have time to press down on the space bar (or any other key you instruct subjects to hold down). When you specify an RTR response, DirectRT will check to see if a key is being held down when the RT starts. If so, it will record the time it took for the subject to release that key and write it to the data file in a column labeled "Release". The response time for the subsequent response is independent of the release time (i.e., it begins at the onset of the stim and consequently includes the key release time).