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									Brief Implicit Association Test (BIAT)
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Main Inquisit programming: Sean Draine (seandr@millisecond.com)
last updated:  10-04-2019 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC

Script Copyright © 10-04-2019 Millisecond Software

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.

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

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BACKGROUND INFO 	
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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 'Flowers-Good' than for 'Insects-Good'
Negative d-scores: support a stronger association between 'Insects-Good' than for 'Flowers-Good'


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)

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

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DURATION 
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the default set-up of the script takes appr. 3.5 minutes to complete

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

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

build:							The specific Inquisit version used (the 'build') that was run
computer.platform:			the platform the script was run on (win/mac/ios/android)
date, time, 					date and time script was run 

subject, group, 				with the current subject/groupnumber
										Note: odd/even groupnumbers balance the order in which 
										hypothesis-compatible/incompatible blocks are run
										odd = compatible - incompatible
										even = incompatible - compatible
										
script.sessionid:				with the current session id

blockcode, blocknum:		the name and number of the current block (built-in Inquisit variable)
trialcode, trialnum: 			the name and number of the currently recorded trial (built-in Inquisit variable)
									Note: trialnum is a built-in Inquisit variable; it counts all trials run; 
									even those that do not store data to the data file such as feedback trials
										
response:						the final trial response (scancodes of the keys pressed)
										18 = E
										23 = I
										57 = spacebar press
										Note: script saves the final and -by design- correct response for each trial
										
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 in ms; measured from onset of stim
stimulusnumber:				the number of the current stimulus
stimulusitem:					the currently presented item


Only meaningful for the last row of data in the raw data file (upon completion of IAT):

expressions.d1:				d-score of the first blocks
expressions.d2 (if run):	d-score of the second blocks (run in extended version)
expressions.d:					overall d-score 
										for extended version: non-weighted mean of the 2 d-scores); main DV
										otherwise: the overall D-score is simply the D-score of the first blocks

									Suggested Interpretation:

											D-score <= -0.65 => "a strong" preference for hypothesis-NONconforming pairings
											D-score < -0.35 => "a moderate" preference for hypothesis-NONconforming pairings
											D-score < -0.15 => "a slight" preference for hypothesis-NONforming pairings																						
											-0.15 <= D-score <= 0.15 "little to no" preference
											D-score > 0.15 => "a slight" preference for hypothesis-conforming pairings
											D-score > 0.35 => "a moderate" preference for hypothesis-conforming pairings
											D-score >= 0.65 => "a strong" preference for hypothesis-conforming pairings

expressions.percentcorrect:       the overall percent correct score of initial responses in test trials of D-score qualifying latencies

expressions.propRT300:		the proportion of response latencies < 300ms

expressions.excludeCriteriaMet:1 = yes, exclusion supported per Greenwald et al (2003, p.214, Table 4):
								More than 10% of all response latencies are faster than 300ms
							0 = otherwise
									

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

computer.platform:			the platform the script was run on (win/mac/ios/android)
script.startdate:				date script was run
script.starttime:				time script was started
script.subjectid:				assigned subject id number
script.groupid:				assigned group id number
script.sessionid:				assigned session id number
script.elapsedtime:			time it took to run script (in ms); measured from onset to offset of script
script.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 (if run):	d-score of the second blocks (run in extended version)
expressions.d:					overall d-score 
										for extended version: non-weighted mean of the 2 d-scores); main DV
										otherwise: the overall D-score is simply the D-score of the first blocks

									Suggested Interpretation:

											D-score <= -0.65 => "a strong" preference for hypothesis-NONconforming pairings
											D-score < -0.35 => "a moderate" preference for hypothesis-NONconforming pairings
											D-score < -0.15 => "a slight" preference for hypothesis-NONforming pairings																						
											-0.15 <= D-score <= 0.15 "little to no" preference
											D-score > 0.15 => "a slight" preference for hypothesis-conforming pairings
											D-score > 0.35 => "a moderate" preference for hypothesis-conforming pairings
											D-score >= 0.65 => "a strong" preference for hypothesis-conforming pairings

expressions.percentcorrect:       the overall percent correct score of initial responses in test trials of D-score qualifying latencies

expressions.propRT300:		the proportion of response latencies < 300ms

expressions.excludeCriteriaMet:1 = yes, exclusion supported per Greenwald et al (2003, p.214, Table 4):
								More than 10% of all response latencies are faster than 300ms
							0 = otherwise

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EXPERIMENTAL SET-UP 
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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.

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STIMULI
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Stimuli can be edited under section Editable Stimuli

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INSTRUCTIONS 
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Instructions can be edited under section Editable Instructions

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EDITABLE CODE 
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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.