Randomization error, while script appears correct. Help !


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evas
evas
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Posts: 5, Visits: 10
So in my script, I ask people to rate some pictures. There are 16 stimuli (and by a programming error 18 trials). I specified noreplace way of drawing (see full code at the end of the post).
This way it should show all 16 stimuli and ask for a rating (then cause of the programming error it ask for a rating for 2 random stimuli again that people have seen before).
Dealing with the programming error was easy, just exclude trail 17 and 18 and then move on with your life happily and blissfully.
However, something very strange seems to be happening. Here is an example of how data (that is generated by me playing the participant).

trialnum:      stimulusnumber1:
1                        10
2                         6
3                         9
4                         8
5                         7
6                         3
7                         5
8                         4
9                        11
10                       2
11                       14
12                       1
13                       16
14                       13
15                       13
16                       12
17                        7
18                        3

As you can see trial 17&18 behave according to the programming error and show a stimulus that has been shown before. However, as you can also see trial 14 and 15 ALSO show this error. Despite the noreplace command.
Even weirder is that there seems to be no system to this error. In this case trial 15 is where it "went wrong" but for other people its another trial.
Also basically for every person it differs which stimulus is shown twice and also which stimulus is not shown. There are even cases were 2 stimuli are shown twice and 2 stimuli are omitted.
To top it off, i have 2 different rating scales, one works perfect and the other has the problem. In the code below, likertpos works fine, likertlight shows this problem. As you can also see in the script they are programmed the same way.
Any idea what is going wrong here ????????????????




SCRIPT:


<block likertlight>
/ preinstructions=(lightness)
/ trials = [1-18 = lightness]
</block>

<item pictures>


/1 = "Black_10%_R000.png"
/2 = "Black_10%_R090.png"
/3 = "Black_10%_R180.png"
/4 = "Black_10%_R270.png"
/5 = "Black_20%_R000.png"
/6 = "Black_20%_R090.png"
/7 = "Black_20%_R180.png"
/8 = "Black_20%_R270.png"
/9 = "Black_80%_R000.png"
/10 = "Black_80%_R090.png"
/11 = "Black_80%_R180.png"
/12 = "Black_80%_R270.png"
/13 = "Black_90%_R000.png"
/14 = "Black_90%_R090.png"
/15 = "Black_90%_R180.png"
/16 = "Black_90%_R270.png"
</item>



<picture patches>
/ size = (55%, 55%)
/ items = pictures
/ position = (50, 45)
/ select = noreplace
</picture>

<text questionlight>
/ items = ("Wie hell ist dieses Farbfeld?")
/ position = (50,80)
/ fontstyle = ("Arial", 2.04%, false, false, false, false, 5, 1)
</text>



<surveypage lightness>
/ stimulusframes = [1=patches, questionlight]
/ nextbuttonposition = (48,92)
/ navigationbuttonsize = (5,3)
/ questions = [1=box]
/ showquestionnumbers = false
/ showpagenumbers = false
</surveypage>



<radiobuttons box>
/ options = ("1=dunkel", "2", "3", "4", "5", "6", "7=hell")
/ required = true
/ orientation = horizontal
/ position = (39,87)
/ fontstyle = ("Arial", 1.48%, false, false, false, false, 5, 1)

</radiobuttons>




<page lightness>
Wie "hell" schätzen Sie die folgenden 16 Bilder auf einer Skala von 1 (sehr dunkel) bis 7 (sehr hell) ein?
Bitte wählen Sie eine Option mit der linken Maustaste aus und klicken Sie dann auf den "Continue-Button".
</page>

<instruct >
/ fontstyle = ("Arial", 3.18%, false, false, false, false, 5, 1)
/ screencolor = #808080
</instruct>





++++++++++++++++++++++++++++++++++++

<block likertpos>
/ preinstructions=(positivity)
/ trials = [1-18 = positivity]

</block>



<surveypage positivity>
/ stimulusframes = [1=patches, questionpos]
/ nextbuttonposition = (48,92)
/ navigationbuttonsize = (5,3)
/ showquestionnumbers = false
/ showpagenumbers = false
/ questions = [1=box2]
</surveypage>




<radiobuttons box2>
/ options = ("1=negativ", "2", "3", "4", "5", "6", "7=positiv")
/ required = true
/ orientation = horizontal
/ position = (39,87)
/ fontstyle = ("Arial", 1.48%, false, false, false, false, 5, 1)
</radiobuttons>



<page positivity>
Wie "positiv" schätzen Sie die folgenden 16 Bilder auf einer Skala von 1 (sehr negativ) bis 7 (sehr positiv) ein?
Bitte wählen Sie eine Option mit der linken Maustaste aus und klicken Sie dann auf den "Continue-Button".
</page>


<text questionpos>
/ items = ("Wie positiv ist dieses Farbfeld?")
/ position = (50,80)
/ fontstyle = ("Arial", 2.04%, false, false, false, false, 5, 1)
</text>




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