How to make the blank screen stay after the keypress?

rampriya darshini

In my experiment stimuli are presented in series.In between each stimuli ,a blank screen appears for 1600 ms during which participants need to give a response according to the stimuli.I want the blank screen to stay for 1600 ms after the key press. Because now that i havea blank screen( whose duration is set to zero) followed by a key response (duration set to 1600ms) in the sequence , it makes the sequence move faster than it ought to be. plz help.

DahmSF

Dear rampriya,

have you tried setting the duration of the blank screen to 1600ms?
Keep the key response and everything equal.
Should work i think.

Stephan

eduard

Alternatively, you can also just add another sketchpad with a black screen right after the keyboard item.
Alternative 2: Add an inline_script with the single line clock.sleep(1600).

Eduard

rampriya darshini

@eduard @DahmSF Thanks for the response.I think I didn't make myself clear.I want the keyboard response to be collected while the blank screen stays for 1600 ms. Inter stimulus interval needs to be strictly 1600ms. And participants gets to press the key only during that time window.

Josh

Hi,

You want to place the keyboard item in between two blank screen sketchpads. The first sketchpad has a duration of 0 ms, the keyboard item has a timeout of 1600 ms, and the second sketchpad has a duration of 1600 - response_time.

That should work.

Cheers,

Josh

rampriya darshini

@Josh Thanks.

rampriya darshini

@Josh I have problem. When I set it as 1600 - response_time, the experiment stops with message invalid duration.

Josh

Hi, sorry about that, I forgot that response_time should be in brackets: [response_time]

Cheers

rampriya darshini

I tried but it says the variable doesn't exist, though the variable exists in the variable inspector. I don't know where i'm making the mistake.

rampriya darshini

@Josh let me just brief about the keyboard responses in my experiment to make myself clear.the experiment i'm designing is a modified no go tasks in which participants need to press a key to indicate that they have failed to withhold their response on no go condition. so there are two key responses. A GO response on go trials and an error response on no go trials. so i inserted two blank screen, one to be presented only during go trial with duration set to [response_time_GO_response]and the other presented only during no go with duration set to [response_time_error_response]. plz help me find where i'm going wrong.

rampriya darshini

Now i understand why the error happened. I inserted an inline script in the run phase,
fixed_dur = 1600
self.sleep(fixed_dur - self.get("response_time"))
it seems to work. is this right? is there a way to cross check whether the timing of the experiment is as intended it to be.

eduard

Every item in Opensesame has a time stamp that is written to the logfile. Try to find the ones that you want to compare and see whether the difference between them is as expected. If you need other times that are stored by default, you can take sound samples at any times (time1 = clock.time()) and compare those then.

Eduard