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PARAMETERS/VALUES
****************************
<parameters>
/substitution_post_stim_pause = 100
/substitution_feedback_duration = 500
</parameters>
<values>
/trialtype = ""
/substitution_complete = 0
/task_order = 99
</values>
Symbol to display is determined by current_symbol, which is set randomly at start of each trial.
<values>
/ current_symbol = ""
/ total_digit_sub_trials = 0
</values>
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SYMBOL RANDOMIZATION
********************
A list to select which of the nine symbols to display, and thus determine which answer is correct:
<list random_pick>
/ items = (1-9)
/ select = random
/ resetinterval = 1
</list>
The symbols themselves:
<item symbols>
/1 = "Л"
/2 = "◇"
/3 = "ϴ"
/4 = "Ш"
/5 = "σ"
/6 = "Џ"
/7 = "Г"
/8 = "Λ"
/9 = "Ҩ"
</item>
The key (from original implementation of DSST):
<picture key_pic>
/items = ("key.png")
/vposition = (75%)
/ erase = false
</picture>
*************
STIMULI
*************
The symbol display itself:
<text symbol_display>
/ items = ("<% getitem(item.symbols, values.current_symbol) %>")
/ fontstyle = ("Helvetica", 25%)
/ vposition = 33%
</text>
Feedback in case of error, and helpful instructions:
<text DSST_error>
/ items = ("X")
/ vposition = 33%
/ fontstyle = ("Helvetica", 40%)
/ color = red
/ halign = center
/ hjustify = center
</text>
<text DSST_feedback>
/ items = ("Refer to key below")
/ vposition = 50%
/ fontstyle = ("Helvetice", 5%)
</text>
Feedback if correct:
<text DSST_correct>
/ items = ("✓")
/ vposition = 33%
/ fontstyle = ("Helvetica", 40%)
/ color = green
/ halign = center
/ hjustify = center
</text>
*************
TRIALS
*************
<trial DSST_main>
/ ontrialbegin = [ values.current_symbol = list.random_pick.nextvalue ]
/ stimulustimes = [ 0 = symbol_display ]
/ validresponse = ("1", "2", "3", "4", "5", "6", "7", "8", "9")
/ correctresponse = (values.current_symbol)
/ ontrialend = [ values.total_digit_sub_trials += 1 ]
/ branch = [ trial.DSST_main ]
/ posttrialpause = parameters.substitution_post_stim_pause
</trial>
<trial DSST_practice>
/ ontrialbegin = [ values.current_symbol = list.random_pick.nextvalue ]
/ stimulustimes = [ 0 = symbol_display ]
/ validresponse = ("1", "2", "3", "4", "5", "6", "7", "8", "9")
/ correctresponse = (values.current_symbol)
/ posttrialpause = parameters.substitution_post_stim_pause
/ errormessage = true(text.DSST_error, parameters.substitution_feedback_duration)
/ correctmessage = true(text.DSST_correct, parameters.substitution_feedback_duration)
</trial>
<block digit_sub_practice>
/ onblockbegin = [ values.trialtype = "Practice" ]
/ trials = [ 1-10 = DSST_practice]
/ bgstim = (key_pic)
/ branch = [ block.digit_sub_main ]
</block>
<block digit_sub_main>
/ onblockbegin = [ values.trialtype = "DSST" ]
/ trials = [ 1 = DSST_main]
/ bgstim = (key_pic)
/ timeout = 120000
/ onblockend = [
values.task_order += 1;
values.substitution_complete = values.task_order;
values.trialtype = "";
]
</block>