Millisecond Forums » Millisecond Forums » Inquisit 5 » 1 minute continuous 2-back (letters)?

1 minute continuous 2-back (letters)?

drtb — Wed, 07 Jun 2017 12:22:17 GMT

Quick question – the n-back script is awesome in that it is highly customizable, but difficult for a non-programming dummy such as myself to pare down for what we need. If I wanted to only run a 1 minute continuous 2-back (letters), keeping the core elements as-is (i.e., randomized presentation of the 20 consonants, 1:2 match ratio, 500ms stimulus prompt with 2000ms window for response, etc.) and removing all the practice elements and other n-backs, are there some quick deletes to the script that I can make just to reduce the sucker down? I figured out how to edit the appropriate images in order to display the instructions we want, but am scratching my head with the rest. Any guidance?

Thanks,
-`-Tim

drtb — Wed, 07 Jun 2017 12:22:17 GMT

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[b]Dave - Wednesday, May 31, 2017[/b]

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[b]drtb - Tuesday, May 30, 2017[/b]

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[b]Dave - Tuesday, May 30, 2017[/b]

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[b]drtb - Tuesday, May 30, 2017[/b]

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I don't think you need to delete much if anything -- setting either a /timeout at the <block> level or a /stop condition at <expt> level that terminates the thing after ~1 minute should get you most of the way there (something like /stop = [script.elapsedtime >= 60000]). The rest -- only administering n-level 2, etc. -- you should be able to handle via the built-in customization options / parameters.

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OK, I changed two lines in the script which seems to have gotten me about 80% there. Specifically, changing the <list Nlevel> to only include single "2" in the item line limited the experiment to a single 2-back block. Additionally, in the <block s_ntask>, I found that changing the / trials line to include more than the "2-16 = no replace" extended the block, such that changing the 16 to a value of 49 turned it into a 2 minute exercise. Two unresolved items:

* the 2:1 non-target to target ratio seems a bit too low - how would I go about changing that to a 3:1 ratio (i.e., 3 non-targets to every target)?

* I still can't find a way of getting rid of the 0, 1, and 3 instruction slides, or getting rid of the 0-back practice block. How do I get it so that it really only shows the intro slide, the 2-back slide, and then skips ahead to where it jumps right to the "2-back" instruction slide (which I believe is the html file)?

Thanks!!!

-`-Tim

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#1 "* the 2:1 non-target to target ratio seems a bit too low - how would I go about changing that to a 3:1 ratio (i.e., 3 non-targets to every target)?"

Look at the <block> element's /trials attribute: Change the ratio in the noreplace() selection pool accordingly.

#2 To not run the practice block, remove it from the <expt> element's /blocks attribute. You should not need to "get rid" of the 0,1, and 3 instruction slides. Leave them in/ as-is .Instructions should be selected according to the selected n-level. I.e., if you run a 2-back, you should automatically see instructions to the 2-back. But since I don't know what specific changes you made to the script, I cannot tell whether you inadvertently broke that functionality.

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OK awesome, this helped immensely, thanks!!! :-)

RE: 1 minute continuous 2-back (letters)?

Dave — Wed, 31 May 2017 09:09:05 GMT

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[b]drtb - Tuesday, May 30, 2017[/b]

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[b]Dave - Tuesday, May 30, 2017[/b]

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[b]drtb - Tuesday, May 30, 2017[/b]

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RE: 1 minute continuous 2-back (letters)?

drtb — Tue, 30 May 2017 23:05:07 GMT

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[b]Dave - Tuesday, May 30, 2017[/b]

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[b]drtb - Tuesday, May 30, 2017[/b]

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drtb — Tue, 30 May 2017 22:28:57 GMT

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[b]Dave - Tuesday, May 30, 2017[/b]

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[b]drtb - Tuesday, May 30, 2017[/b]

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Thank you very much for the reply Dave, however I'm afraid I'm still hopelessly lost.

I don't understand how all of the instruction pages for the practice and experiment portions across all "N" levels of n-back interrelate. For example, I am not interested in doing anything except a 2-back, so when I delete the 0, 1, and 3-back instructions, it seems to break the experiment.

I do appreciate your suggestion for edits at the experiment or block level, but wouldn't that simply increase the number of blocks? I believe right now that each block is contained to present 5 targets and 10 non-targets, however I want to run just one continuous block with "X" targets and "X times 2" non-targets until 1 minute has expired. My understanding is that your suggested code would just keep running 15-trial blocks until a minute has passed. Is that correct, or have I missed something?

Again, love the customization of this, but I just keep finding myself more and more lost in the vast amount of options (i.e., as opposed to the relatively straightforwardness of the PVT). At the end of the day, I just want to show some custom 2 or 3 picture instruction pages (which I somehow successfully managed to add), run a single continuous 1-minute 2-back letter block, and then display some end page.

RE: 1 minute continuous 2-back (letters)?

Dave — Tue, 30 May 2017 20:57:23 GMT

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[b]drtb - Tuesday, May 30, 2017[/b]

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