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n-back summary data

KathyB — Wed, 11 Nov 2015 16:59:45 GMT

Hi,
I'm using the single task version of the N-Back (yellow shapes, non-adaptive) from the Test Library and haven't modified it at all except that I'm only running the 1-back and 2-back tasks (3 blocks of each). I'm doing some analysis now, and wondering: How can I quickly extract the number of hits, misses, and false alarms, separately for 1-back and 2-back blocks? The summary file that is generated at the moment contains total hits and total false alarms, but they're not broken down by block, and I need to compare 1-back performance with 2-back performance. Any tips on how I could modify the summary data script to make this happen would be greatly appreciated. And would be quicker than working it out from the raw data after the fact.
Thank you,
Kathy

RE: n-back summary data

KathyB — Wed, 11 Nov 2015 16:59:45 GMT

That has worked perfectly - thank you kindly for such a quick reply and such detailed instructions.

RE: n-back summary data

Dave — Wed, 11 Nov 2015 04:23:08 GMT

#1: Create a bunch of new <values> entries to hold the respective statistics. E.g.

<values>
/ n1hits = 0
/ n2hits = 0
...
</values>

(same for false alarms, etc.)

#2: Aggregate those statistics according to n-level at the end of the <block>, e.g.

<block s_ntask>
/ onblockbegin = [
                        values.currenttarget = 0; values.minus1 = 0; values.minus2 = 0; values.minus3 = 0; values.minus4 = 0;
                        values.Hits = 0; values.FalseA = 0; values.Misses = 0; values.CorrReject = 0;
                        values.TotalBlocks += 1;
                        values.starttrialcounter = 0;
                        values.repetitioncounter += 1;
                        ]
/ onblockend = [if (values.n==1) {values.n1hits+=values.Hits; }; ]
/ onblockend = [if (values.n==2) {values.n2hits+=values.Hits; }; ]
/ trials = [1 = expinstructiontrial; 2 = start; 3 - 22 = noreplace(nontarget, nontarget, nontarget, nontarget, nontarget, nontarget, nontarget,
                                                                                target, target, target)]
...
</block>

(same for false alarms, etc.)

#3: Add the newly created values to the summary data output:

<summarydata >
/file = "SingleTaskNback_summary.iqdat"
/columns = [script.startdate, script.starttime, script.subjectid, script.groupid, script.elapsedtime, values.completed,
values.TotalHits, values.TotalFA, values.DV, values.n1hits, values.n2hits, ... ]
</summarydata>

(same for false alarms, etc.)