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									Implicit Attitude Test (IAT) - with pictures
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

The Implicit Association Task (Greenwald, McGhee, & Schwartz, 1998) is a widely-used cognitive-behavioral paradigm
that measures the strength of automatic (implicit) associations between concepts in people’s minds relying 
on latency measures in a simple sorting task.
 
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' and 'Insects-Bad' than for the opposite pairings
Negative d-scores: support a stronger association between 'Insects-Good' and 'Flowers-Bad' than for the opposite pairings

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.


											  *Task*
Participants are asked to categorize attributes (e.g. "joyful"; "tragic") and and target items (e.g "daisy" vs. "wasp")
into predetermined categories via keystroke presses. The basic task is to press a left key (E) if an item (e.g. "joyful")
belongs to the category presented on the left (e.g. "Good") and to press the right key (I) if the word (e.g. "tragic") 
belongs to the category ("Bad") presented on the right.
For practice, participants sort items into the target categories "Flowers vs. Insects" and the attribute categories "Good vs. Bad".
For the test, participants are asked to sort categories into the paired/combined categories (e.g. 
"Flower OR Good" on the left vs. "Insect OR Bad" on the right). Pairings are reversed for a second test 
(e.g. "Insects OR Good" on the left vs. "Flowers OR Bad" on the right). Order is counterbalanced by groupnumber.	

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

(1) Raw data file: 'IAT_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, blocknum:			the name and number of the current block
trialcode, trialnum: 			the name and number of the currently recorded trial
									(Note: not all trials that are run might record data; by default data is collected unless /recorddata = false is set for a particular trial/block) 
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 in ms
stimulusnumber:					the number of the current stimulus
stimulusitem:					the currently presented item
expressions.da:					d-score of the first blocks
expressions.db:					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: 'IAT_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.da:					d-score of the first blocks
expressions.db:					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:
1. Target Category sorting training
2. Attribute sorting training
3. 1. Test Block of hypothesis-consistent* pairings with 20 trials (half the participant start with inconsistent pairings)
4. 2. Test Block of hypothesis-consistent pairings with 40 trials
5. Target Category sorting training with targets switching sides
6. 1. Test Block of hypothesis-inconsistent pairings with 20 trials
7. 2. Test Block of hypothesis-inconsistent pairings with 40 trials

In all Test Blocks:
* attributes and targets alternate
* attributes as well as targets are randomly selected without replacement

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:

/showsummaryfeedback:		set parameter showsummaryfeedback = true to display summary feedback to participants at the end (default)
							set parameter showsummaryfeedback = false if no summary feedback should be presented to participants

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