11-11-2021, 10:58 AM
(This post was last modified: 11-11-2021, 11:43 AM by [email protected].)
Good morning!
I have a question about catch trials and if it is possible for me to implement them in my study given my study design. I have 224 experimental trials total (seven blocks of 32 trials), and I am hoping to put six short breaks after the first six blocks of trials. My trials are randomized, so if I put the blocks into my block sequence in my procedure, the breaks get randomized with the trials (which I don't want).
From the grammar reference, it seems that catch trials would be the best way to implement these consistent breaks into randomized trials. However, I'm not sure if I will be able to use catch trials with my study design. I was wondering if you could help me determine that?
In my study, each trials has a sequence of six stimuli: a response cue, a blank grid which acts as a pause, a "cued response", another blank grid, a "discrimination response" and finally, one more blank grid.
The response cue, which is presented first, auto-advances after 5ms. Then the blank grid is presented, which also auto-advances after 5ms. Then the "cued response" stimulus is presented, to which participants make a keypress response. This stimulus will not advance until participants make a keypress. Participants then see another blank grid which auto-advances after 5ms to the final stimulus, the "discrimination response" stimulus, to which participants must make another keypress before the trial ends.
The trial templates are set up so that there's a template for the response cue + first pause (called e.g "Trial8 RC"), a template for the cued response stimulus + discrimination response stimulus (called e.g "Trial8Critical"), and a template for the two pauses that follow the cued response and then the discrimination response stimuli, respectively (called e.g "Trial8Pauses").
"Trial8 RC": {
"type": "basic",
"stimuli": ["ResponseCueLeft", "BlankGrid5"],
"auto_advance": true
},
"Trial8Critical": {
"type": "basic",
"stimuli": ["GreenBottomCRS", "BlueTopCRS"],
"responses": ["TrainingResponseTargetF", "TrainingResponseTargetJ"]
},
"Trial8Pauses": {
"type": "basic",
"stimuli": ["BlankGrid5", "BlankGrid2"],
"auto_advance": true
The response cue stimulus has a stimulus level duration of 0.5 seconds and the barrier set to "true" and the trial-template is set to auto-advance.
In the procedures, this is set up so that the block will look as follows:
"TrialBlock5": {
"trial_templates": ["Trial5Critical", "Trial5Pauses"],
"pattern": {"order": "alternate", "repeat": 1},
"cover_trials": ["Trial5 RC"].
The reason I don't think I can incorporate catch trials into my study is because I already have the "Trial[x] RC" as a cover trial. If I put the "Trial[x] RC" templates into the "trial_templates": [...], along with the Trial[x]Critical and Trial[x]Pause, then I won't be able to alternate the pauses between the two critical stimuli, because FF won't be able to evenly distribute the stimuli. I've tried using the catch trials with the cover trial (like how you can have a cover and end trial) but the stimuli were presented out of order.
Do you have any thoughts on this?
Thank you so much!
Grace
Hi again,
It seems that the font in my first paragraph in my above post is unreadably small. I will copy and paste it here:
"I have a question about catch trials. I have 224 experimental trials total (seven blocks of 32 trials), and I am hoping to put six short breaks after the first six blocks of trials. My trials are randomized, so if I put the blocks into my block sequence in my procedure, the breaks get randomized with the trials (which I don't want)."
Sorry about that!
I have a question about catch trials and if it is possible for me to implement them in my study given my study design. I have 224 experimental trials total (seven blocks of 32 trials), and I am hoping to put six short breaks after the first six blocks of trials. My trials are randomized, so if I put the blocks into my block sequence in my procedure, the breaks get randomized with the trials (which I don't want).
From the grammar reference, it seems that catch trials would be the best way to implement these consistent breaks into randomized trials. However, I'm not sure if I will be able to use catch trials with my study design. I was wondering if you could help me determine that?
In my study, each trials has a sequence of six stimuli: a response cue, a blank grid which acts as a pause, a "cued response", another blank grid, a "discrimination response" and finally, one more blank grid.
The response cue, which is presented first, auto-advances after 5ms. Then the blank grid is presented, which also auto-advances after 5ms. Then the "cued response" stimulus is presented, to which participants make a keypress response. This stimulus will not advance until participants make a keypress. Participants then see another blank grid which auto-advances after 5ms to the final stimulus, the "discrimination response" stimulus, to which participants must make another keypress before the trial ends.
The trial templates are set up so that there's a template for the response cue + first pause (called e.g "Trial8 RC"), a template for the cued response stimulus + discrimination response stimulus (called e.g "Trial8Critical"), and a template for the two pauses that follow the cued response and then the discrimination response stimuli, respectively (called e.g "Trial8Pauses").
"Trial8 RC": {
"type": "basic",
"stimuli": ["ResponseCueLeft", "BlankGrid5"],
"auto_advance": true
},
"Trial8Critical": {
"type": "basic",
"stimuli": ["GreenBottomCRS", "BlueTopCRS"],
"responses": ["TrainingResponseTargetF", "TrainingResponseTargetJ"]
},
"Trial8Pauses": {
"type": "basic",
"stimuli": ["BlankGrid5", "BlankGrid2"],
"auto_advance": true
The response cue stimulus has a stimulus level duration of 0.5 seconds and the barrier set to "true" and the trial-template is set to auto-advance.
In the procedures, this is set up so that the block will look as follows:
"TrialBlock5": {
"trial_templates": ["Trial5Critical", "Trial5Pauses"],
"pattern": {"order": "alternate", "repeat": 1},
"cover_trials": ["Trial5 RC"].
The reason I don't think I can incorporate catch trials into my study is because I already have the "Trial[x] RC" as a cover trial. If I put the "Trial[x] RC" templates into the "trial_templates": [...], along with the Trial[x]Critical and Trial[x]Pause, then I won't be able to alternate the pauses between the two critical stimuli, because FF won't be able to evenly distribute the stimuli. I've tried using the catch trials with the cover trial (like how you can have a cover and end trial) but the stimuli were presented out of order.
Do you have any thoughts on this?
Thank you so much!
Grace
Hi again,
It seems that the font in my first paragraph in my above post is unreadably small. I will copy and paste it here:
"I have a question about catch trials. I have 224 experimental trials total (seven blocks of 32 trials), and I am hoping to put six short breaks after the first six blocks of trials. My trials are randomized, so if I put the blocks into my block sequence in my procedure, the breaks get randomized with the trials (which I don't want)."
Sorry about that!