Stop removing stimulus after participant response


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jmsaito
jmsaito
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Posts: 9, Visits: 19
Hello,

I have created a standard object encoding task. Participants view a series of images (i.e., real-world objects) that are presented for a fixed amount of time. For each image, participants make a button press to indicate whether the object is larger or smaller than a shoebox.

I want to fix the stimulus presentation to 1500 ms REGARDLESS of participant response. At current, the image is removed from the screen when the response is made, and the remainder of the 1500 ms trial duration is filled with a blank screen. How do I resolve this?

<trial block_trial>
/ ontrialbegin = [
    values.obj = 0;
    values.size_resp = 0;
    values.size_RT = 0;

    expressions.next_obj;
]
/ stimulustimes = [0 = BlankScreen, FixationCross]
/ recorddata = false
/ trialduration = 500
/ branch = [
    trial.obj_decide1
]
</trial>

<trial obj_decide1>
/ stimulustimes = [0 = BlankScreen, current_obj]
/ recorddata = false
/ trialduration = 1500
/ ontrialend = [
    values.size_resp = trial.obj_decide1.response;
    values.size_RT = trial.obj_decide1.latency;    
]
/ branch = [
    if (values.size_resp == 0){
        trial.Warning_Trial    
        }
    else {
        trial.obj_decide2
        };
]
</trial>

Dave
Dave
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Posts: 13K, Visits: 105K
jmsaito - 1/24/2022
Hello,

I have created a standard object encoding task. Participants view a series of images (i.e., real-world objects) that are presented for a fixed amount of time. For each image, participants make a button press to indicate whether the object is larger or smaller than a shoebox.

I want to fix the stimulus presentation to 1500 ms REGARDLESS of participant response. At current, the image is removed from the screen when the response is made, and the remainder of the 1500 ms trial duration is filled with a blank screen. How do I resolve this?

<trial block_trial>
/ ontrialbegin = [
    values.obj = 0;
    values.size_resp = 0;
    values.size_RT = 0;

    expressions.next_obj;
]
/ stimulustimes = [0 = BlankScreen, FixationCross]
/ recorddata = false
/ trialduration = 500
/ branch = [
    trial.obj_decide1
]
</trial>

<trial obj_decide1>
/ stimulustimes = [0 = BlankScreen, current_obj]
/ recorddata = false
/ trialduration = 1500
/ ontrialend = [
    values.size_resp = trial.obj_decide1.response;
    values.size_RT = trial.obj_decide1.latency;    
]
/ branch = [
    if (values.size_resp == 0){
        trial.Warning_Trial    
        }
    else {
        trial.obj_decide2
        };
]
</trial>

> I want to fix the stimulus presentation to 1500 ms REGARDLESS of participant response. At current, the image is removed from the screen when the response is made, and the remainder of the 1500 ms trial duration is filled with a blank screen. How do I resolve this?

Set the stimuli's /erase attributes to false. At a minimum, that's the BlankScreen and current_obj elements.

Edited 3 Years Ago by Dave
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