Clarifying Output Variable Names in Change Blindness Task


Author
Message
skotturi01
skotturi01
Respected Member (404 reputation)Respected Member (404 reputation)Respected Member (404 reputation)Respected Member (404 reputation)Respected Member (404 reputation)Respected Member (404 reputation)Respected Member (404 reputation)Respected Member (404 reputation)Respected Member (404 reputation)
Group: Forum Members
Posts: 1, Visits: 6
I have some data from the Change Blindness task (http://www.millisecond.com/download/library/ChangeBlindness/)

I understand the task and what it's measuring but I cannot decode the variable names Inquisit in outputting nor can I find any documentation explaining the variables. 

For each trial I get the following column names:
values.prechange3_hits, values.prechange3_fas, expressions.prechange3_diff,
values.postchange3_hits, values.postchange3_fas, expressions.postchange3_diff

I understand the pre and post trials, "diff" is just "hits - fas". 
I cannot figure out what "hits" & "fas" are though. 
Hits looks like it could be the serial position of the item that was removed/replaced and fas is the subject response, correct of false. However Fas occasionally takes the value of 2 (almost always 0 or 1 otherwise). These aren't intuitive, abbreviations or acronyms though which makes me think it must be something else. 

Looking for an "AHA" moment :)



Dave
Dave
Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)
Group: Administrators
Posts: 12K, Visits: 98K
If you open the script in Inquisit Lab (or any other text editor -- it's just a text file), you will find all of this documented throughout the comments included in the script. The detailed documentation for the data output starts at line 505.

A relevant excerpt:

/postchange_FAs:  sums up hits/False Alarms (FAs) for prechange and postchange recognition
/prechange3_diff:   difference in values.prechange_hits - values.prechange_FAs for array number = 3 (same for all array numbers)
/postchange3_diff: difference in values.postchange_hits - values.postchange_FAs for array number = 3 (same for all array numbers)

Hits and False Alarms are standard technical terms in Signal Detection Theory. See e.g. https://en.wikipedia.org/wiki/Detection_theory#Psychology

GO

Merge Selected

Merge into selected topic...



Merge into merge target...



Merge into a specific topic ID...




Reading This Topic

Explore
Messages
Mentions
Search