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						Brief Implicit Association Test (BIAT) - Depression BIAT
SCRIPT INFO

Main Inquisit programming: Sean Draine (seandr@millisecond.com)
last updated:  02-25-2016 by K.Borchert (katjab@millisecond.com) for Millisecond Software LLC

Script Copyright ©  02-25-2016 Millisecond Software


BACKGROUND INFO: Specific BIAT

The University of Washington has applied for patent on the BIAT method. The patent 
is managed by Project Implicit. Both the University of Washington and Project Implicit 
authorize free use of the BIAT method and published stimuli for scholarly research, 
provided that reports of the research clearly identify any modifications made to the 
BIAT and appropriately cite the present article. Please contact Project Implicit 
(E-mail: feedback@projectimplicit.net) to request a license for commercial or other 
nonscholarly use of the BIAT.


The brief IAT (BIAT) procedure is explained in detail in:

Sriram, N. & Anthony G. Greenwald, A.G (2009).The Brief Implicit Association Test.
Experimental Psychology, 56, 283–294. (see page. 285, Table 1 for an overview of the procedure)

Millisecond Software thanks Dr. Sriram and Dr. Greenwald for providing generous feedback on this script!



BACKGROUND INFO: General IAT/BIAT

The Implicit Association Task (IAT: Greenwald, McGhee, & Schwartz, 1998) and the brief IAT (BIAT: Sriram & Greenwald, 2009)
are widely-used cognitive-behavioral paradigms that measure the strength of automatic (implicit) associations 
between concepts in people’s minds relying on latency measures in simple sorting tasks.
 
The strength of an association between concepts is measured by the standardized mean difference score of 
the 'hypothesis-inconsistent' pairings and 'hypothesis-consistent' pairings (d-score) (Greenwald, Nosek, & Banaji, 2003). 
In general, the higher the d-score the stronger is the association between the 'hypothesis-consistent' pairings 
(decided by researchers). Negative d-scores suggest a stronger association between the 'hypothesis-inconsistent' pairings.

Inquisit calculates d scores using the improved scoring algorithm as described in Greenwald et al (2003). 
Error trials are handled by requiring respondents to correct their responses according to recommendation (p.214).

D-scores obtained with this script:
Positive d-scores: support a stronger association between 'ME-Sad' than for 'ME-Happy'
Negative d-scores: support a stronger association between 'ME-Happy' than for 'ME-Sad'


References:
Greenwald, A. G., McGhee, D. E., & Schwartz, J. K. L. (1998). Measuring individual differences in implicit cognition: 
The Implicit Association Test. Journal of Personality and Social Psychology, 74, 1464-1480.

Greenwald, A. G., Nosek, B. A., & Banaji, M. R. (2003). Understanding and Using the Implicit Association Test: 
I. An Improved Scoring Algorithm. Journal of Personality and Social Psychology, 85, 197-216.

Sriram, N. & Anthony G. Greenwald, A.G (2009).The Brief Implicit Association Test.
Experimental Psychology, 56, 283–294. (see page. 285, Table 1 for an overview of the procedure)


											  *Task*

Participants are asked to categorize attributes (e.g. "my", "they") and target items (e.g Sad vs. Happy) 
into predetermined categories via keystroke presses. 
For the test, participants are asked to sort categories into  paired/combined categories (e.g. 
"Sad OR ME" on the left vs. "Anything else" on the right). The basic task is to press a left key (E) if an item 
(e.g. "my") belongs to the category presented on the left (e.g. "Sad OR ME") and to press the right key (I) 
if the word (e.g. "they") does not belong to the category on the left. Pairings are reversed for a second test 
(e.g. "Sad OR NOT ME" on the left vs. "Anything else" on the right). Order is counterbalanced by groupnumber.							  
For practice, participants practice two shorter versions of the test.



DATA FILE INFORMATION: 
The default data stored in the data files are:

(1) Raw data file: 'DepressionBriefIAT_raw*.iqdat' (a separate file for each participant)

build:								Inquisit build
computer.platform:					the platform the script was run on
date, time, subject, group:			date and time script was run with the current subject/groupnumber 
										Note: group1/group2 counterbalance the order in which the pairings are run

blockcode:							the name of the current trial
blocknum:							the number of the current trial
trialcode:							the name of the current trial
trialnum:							the number of the current trial
response:							the final trial response (scancodes of the keys pressed)
										Note: script saves the final and -by design- correct response
correct:							the accuracy of the initial response
										0 = initial response was incorrect and needed to be corrected
										1 = initial response is correct
latency:							the latency of the final (correct) response
stimulusnumber:						the number of the current stimulus
stimulusitem:						the currently presented item
expressions.d1:						d-score of the first blocks
expressions.d2:						d-score of the second blocks
expressions.d:						overall d-score
/percentcorrect:       				the overall percent correct score of initial responses of test trials of D-score qualifying latencies

(2) Summary data file: 'DepressionBriefIAT_summary*.iqdat' (a separate file for each participant)

script.startdate:					date script was run
script.starttime:					time script was started
script.subjectid:					subject id number
script.groupid:						group id number
script.elapsedtime:					time it took to run script (in ms)
computer.platform:					the platform the script was run on
/completed:							0 = script was not completed (prematurely aborted); 1 = script was completed (all conditions run)
expressions.d1:						d-score of the first blocks
expressions.d2:						d-score of the second blocks
expressions.d:						overall d-score
/percentcorrect:       				the overall percent correct score of initial responses of test trials of D-score qualifying latencies



EXPERIMENTAL SET-UP

Hypothesis-consistent pairings vs. hypothesis-inconsistent pairings; tested within-subjects 
=> order is counterbalanced by groupnumber assignment

Sequence (odd groupnumbers):
1. Short Block1 (hypothesis-consistent) 
2. Short Block2 (hypothesis-inconsistent)
3. Long Block (hypothesis consistent)
4. Long Block (hypothesis inconsistent)
3. Long Block (hypothesis consistent)* (the last two blocks are skipped if parameters.extended = false)
4. Long Block (hypothesis inconsistent)

In all Test Blocks:
* attributes and targets alternate
* attributes as well as targets are randomly selected without replacement
* short blocks run 14 trials; experimental blocks run 20 trials by default
* the first 4 trials = prefatory trials that are not included into subsequent analyses

NOTE: if a participant goes through a sequence of BIATs the short blocks 
short_a & short_b only need to be run for the very first BIAT in the sequence.
Short Blocks are simply shorter versions (only 4 prefatory trial + 8 trials) of the longer Experimental Blocks. 
They are intended as practice blocks as participants tend to be slower 
during the first two blocks of a BIAT. They are not included into further data analyses.

STIMULI
Stimuli can be edited under section Editable Stimuli

INSTRUCTIONS
Instructions can be edited under section Editable Instructions

EDITABLE CODE:
check below for (relatively) easily editable parameters, stimuli, instructions etc. 
Keep in mind that you can use this script as a template and therefore always "mess" with the entire code to further customize your experiment.

The parameters you can change are:

	The "skipsummary" variable in the values tag can be set to true to skip the final
     summary page or false to display the page.

	The "extended" variable in the values tag can be set to true to run a total of four 
     test blocks, or false to run only 2 test blocks. 

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