GNAT - No Response as Valid

Location:

…\DirectRT\samples\6 v2008\no response as valid

…\DirectRT\samples\6 v2008\gnat

Sample Descriptions

As of v2006, you can use -1 as a keycode to represent "no response" as if it were just like any other key press. That means you can list it with other keycodes, either first to indicate it's the correct answer or later in the list to indicate that it's incorrect. If the subject waits as long as the max value then that's like pressing the "-1" key.

The first sample shows how to do this in the simplest way possible:

~no response	0,0,1	rt:-1,57
~hit space	0,0,1	rt:57,-1

Here we see that no response is correct for the first trial, and hitting the spacebar is correct for the second.

GNAT

The GNAT sample is a first stab at the DirectRT version of the Go/No-go Association Task (GNAT) posted at Project Implicit (see http://projectimplicit.net/nosek/gnat/)

In it, you'll see:

rt:57,-1<-999

rt:-1,57<-999

57 as usual is the keycode for the spacebar. -1 is the new code used to represent no response. <999 normally means jump to trial 999 when the trial is over and then resume. As of v2006, you can add a negative sign as in <-999 to jump NOW without finishing the trial. The subject never sees the rest of the trial. 999 is the X. So if you don’t jump immediately to 999 (and get the X) then you get the O which is at the end of each trial.

Note: see www.empirisoft.com/support/showthread.php?t=94 for notes regarding a bug that had the potential to affect the 'no response' option in versions 2006.1.12 - 2006.1.15.