Millisecond Forums

Stimulus is not erased in Mac

https://forums.millisecond.com/Topic19915.aspx

By Xin- - 10/23/2016

Hello,
I'm using Inquisit to run an online study. I tried different computers to make sure it can run smoothly. Then I got one problem when I ran it on Mac: the stimulus isn't erased on the next trial. Here is the part of the script,

<block h1sh1_h1_d1d2d3>
/ trials = [1 = noreplace(human1_storyh1); 2-4= noreplace(human1_dilemma1,human1_dilemma2, human1_dilemma3)]
</block>

The following stimulus is always on the screen when trial 2-4 are running (it's in Dutch). 
"Omdat hij vindt dat hij toen te ijdel was en zich wilde bewijzen, zonder met zijn vriendin rekening te houden."
"Omdat het hem toen niet gelukt was om de top te bereiken, ondanks zijn ervaring."

I tried different ways to solve it, such as putting blank trial, or blank rectangle between trial 1 and 2, to cover it, but the stimulus is always in front, and can not be covered by blank trial. 
Notice that this problem only happens in Mac, and Windows computers and laptops are working fine. 
I put the material in the attachment. Please ignore the layout of the experiment, but you can see the problem. 
Is there any way to solve this problem?
Thanks in advance.


By Dave - 10/23/2016

I think this may be due to the somewhat odd canvas settings:

<defaults>
...
/ canvassize = (100%,100%)
/ canvasaspectratio = (40, 20)
</defaults>

Can you tell me why you chose those, particularly the 40:20 ratio?
By Xin- - 10/24/2016

Thanks for the quick reply, Dave.
I tried different default settings, and this one makes a fine layout on windows computers. So I keep this ratio as default. 


By Dave - 10/24/2016

It's an odd choice. This gives you something that's essentially equivalent to a screen that's twice as wide as it is high (e.g. 1600 x 800 pixels). There is little vertical space then, and survey pages usually require more vertical space than they require horizontal space.

Anyway, for testing purposes: Could you please *delete* the /canvasaspectratio attribute from the <defaults> element and check if the problem goes away when running on a Mac.
By Xin- - 10/24/2016

Yes, I just tried. But it doesn't work. The stimulus still appears in the next trials. 
By Dave - 10/24/2016

Hmm, okay, thanks. One more thing to try: Split the 1st trial and remaining 3 trials into separate blocks. I.e.:

<block h1sh1_h1_d1d2d3>
/ trials = [1 = noreplace(human1_storyh1)]
/ branch = [block.h1sh1_h1_d1d2d3_pt2]
</block>

<block h1sh1_h1_d1d2d3_pt2>
/ trials = [1-3= noreplace(human1_dilemma1,human1_dilemma2, human1_dilemma3)]
</block>

Does that do the trick?
By Xin- - 10/24/2016

sadly, still no.
This time, even the other stimulus,
"Ja, omdat hij vindt dat hij nu ouder, rustiger en verstandiger is geworden.",
"Nee, omdat weet dat zijn enthousiasme ook bij ongunstige omstandigheden zo groot is, dat hij de risico’s toch blijft accepteren."
together with the first stimulus appear in the next trials. 
By Dave - 10/24/2016

That's really odd -- running out of ideas here. One more: The questions that mysteriously remain on-screen are both <listbox> elements. What happens when you replace them with a different question type, such as <dropdown>, <radiobuttons>, or <checkboxes>?
By Xin- - 10/24/2016

Yeah! It's working! As long as it's not listbox!
I don't know why, but it works!
Thanks, Dave!