help with displaying screen and getting RT

1
Hello,

I hope this is the appropriate place to ask coding questions.

I am trying to display a screen for a specified period of time and I'm
having trouble displaying the image and recording reaction time while
the image remains up.

I'm trying something like this:

starttime=GetSecs; %start RT when first picture is displayed
SCREEN('CopyWindow',scr_one(j),w); % Copy single picture to
monitor.
pic1 = GetSecs;
[keyIsDown, t, keyCode]=KbCheck;
while (GetSecs - pic1 <= 2)
end

if keyCode(1)==1
Response(1,k)=1 %record keystroke 1 if left mouse, 2 if
right mouse
RT=t-starttime;
Response(2,k)=RT %record reaction time to 2xN matrix
k=k+1;


My image displays for the appropriate amount of time but the kbcheck
function isn't recording the keypress. Matlab's pause function and the
waitsecs function don't seem to be what I want either. I am using
Windows XP and Matlab 6.5.1.

Thanks in advance,

Karl Doron
Boston University
2
I'm not sure why you have nothing in youe while loop but could it be that you need to put
your if keyCode(1)==1 line in the while loop??


Pat

--- In psychtoolbox@yahoogroups.com, Karl Doron <karld@b...> wrote:
>
> Hello,
>
> I hope this is the appropriate place to ask coding questions.
>
> I am trying to display a screen for a specified period of time and I'm
> having trouble displaying the image and recording reaction time while
> the image remains up.
>
> I'm trying something like this:
>
> starttime=GetSecs; %start RT when first picture is displayed
> SCREEN('CopyWindow',scr_one(j),w); % Copy single picture to
> monitor.
> pic1 = GetSecs;
> [keyIsDown, t, keyCode]=KbCheck;
> while (GetSecs - pic1 <= 2)
> end
>
> if keyCode(1)==1
> Response(1,k)=1 %record keystroke 1 if left mouse, 2 if
> right mouse
> RT=t-starttime;
> Response(2,k)=RT %record reaction time to 2xN matrix
> k=k+1;
>
>
> My image displays for the appropriate amount of time but the kbcheck
> function isn't recording the keypress. Matlab's pause function and the
> waitsecs function don't seem to be what I want either. I am using
> Windows XP and Matlab 6.5.1.
>
> Thanks in advance,
>
> Karl Doron
> Boston University