How To Ensure That The Keyboard Response Item Operates within a Specified Time Window, D

SRayPsy1

DESCRIPTION OF THE PROBLEM :

1. I am designing an experiment which studies mind-wandering where clock face (with one moving hand) is shown using multiple sketchpad clock faces. The hand should appear to move at the rate of 20 degrees person second.
2. At 12 o clock some specified external task is to be performed which requires key-press. Also, the key press should happen Only During a specified Time window defined with respect to the clock face at 12 O’ clock.
3. I am using a clock face, showing 12 o’ clock,  in a sketch pad, which should show for 1000msec. After that a key-board response is used with time duration 500 msec. Now, as per the paper it is required that  the external task, that of pressing SPACE bar will be considered the correct external task response only if it occurs 50msec Before the clock face reaches 12 o’ clock., and within 500 msec after the clock face shows 12 o clock. Note that the clock face at 12 o’ clock is shown for 1000 msec., after which the keyboard response is shown for only 500 msec. 
4. If the components are implemented sequentially then the keyboard response becomes operative only after the clock face has been shown for 1000msec. 
5. QUESTION/ PROBLEM: What are the methods using which the keyboard response can be taken 50msec Before the clock face reaches 12 o’ clock., and within 500 msec after the clock face shows 12 o clock? 

Thanks, S. RAY

eduard

Hi Ray, I am sorry, but I am not sure I am understanding what exactly it is that you want to accomplish.

What I gather is following:

You have a sketchpad that needs to be updated once per second (moving hand). It is a clock, so every 12 seconds it will be back at the initial position. You have a secondary task that does not interact with the visual presentation. This secondary task is to press a key within a certain time range. This time range is 50 ms before the hand is hitting 12 o'clock until 500 ms after 12 o'clock. Your question is, how to sample a keyboard response at the right time without interfering with the clock?

Is that correct?

after which the keyboard response is shown

Keyboard responses are not shown. They won't change whatever happens on the screen. What exactly do you mean here?

In any case, you will most likely have to use inline_script items. Is this for an online experiment? In that case, things will become considerably more complicated as you can't easily draw stimuli on the fly.

Hope this helps,

Eduard