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									Single Category (SC) Implicit Attitude Test (IAT)
SCRIPT INFO

Main Inquisit programming: Sean Draine (seandr@millisecond.com)
last updated: 01-12-2016 by K.Borchert (katjab@millisecond.com) for Millisecond Software LLC

Copyright © 01-12-2016 Millisecond Software


BACKGROUND INFO

The SC-IAT script is based on:

Karpinski, A. & Steinman, R.B. (2006). The Single Category Implicit Association Test as a Measure of Implicit
Social Cognition. Journal of Personality and Social Psychology, 91, 16–32.

and the general IAT.iqx script published by Millisecond Software LLC

Differences btw. this script and Karpinski & Steinman (2006)
- error responses in this script need to be corrected before moving on
- no response window:
stimuli stay on screen until a correct response is given. A reminder to "respond more quickly" is
optional if latencies exceed a certain limit (see section "Editable Values" for more info)
- no error response correction necessary for d-score calculation as error responses needed to be corrected
before moving on (therefore an error penalty was added automatically to each error latency)


IAT-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).
This differs slightly from Karpinski & Steinman (2006) who removed noresponse trials from d-score calculations and 
replaced error responses with the mean latency + 400ms penalty.

D-scores obtained with this script:
positive D-scores: positive attitude towards animals
negative D-scores: negative attitude towards animals

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 insect pictures
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. "Animal OR Good") and to press the right key (I) if the word (e.g. "tragic") 
belongs to the category presented on the right ("Bad") . Pairings are reversed for a second test: 
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 presented on the right ("Animal OR Bad").
The order of the pairings is counterbalanced by groupnumber.
							  


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

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

build:								Inquisit build
computer.platform:					the platform the script was run on
date/time/group/subject:			built in variables that track date and time when script was run with the assigned
									subject- and group number

									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.d:						overall d-score
/ latdiff:							difference between mean latencies in incompatible and compatible block
/percentcorrect:       				the overall percent correct score of initial responses of compatible and incompatible trials
									with qualifying latencies


(2) Summary data file: 'SC_IATpic_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; 1 = script was completed (all conditions run)

/ m1:					mean latencies of correct responses in compatible block
/ m2:					mean latencies of correct responses in incompatible block
/ sd1:					standard deviation of latencies of correct responses in compatible block
/ sd2:					standard deviation of latencies of correct responses in incompatible block
/d:						overall d-score
/ latdiff:				difference between mean latencies in incompatible and compatible block
/percentcorrect:       	the overall percent correct score of initial responses of compatible and incompatible trials
						with qualifying latencies



EXPERIMENTAL PROCEDURE:
a) Block Practice Compatible* (24 trials); responses not counted towards D-score
b) Block Compatible (72 trials)
c) Block Practice InCompatible (24 trials); responses not counted towards D-score
d) Block InCompatible (72 trials)

*order compatible - incompatible counterbalanced by groupnumber
=> one D-score is determined 

TRIALS
After a pretrialpause of 250ms (default, editable), stimuli are presented until correct response is given. 
In contrast to Karpinski & Steinman (2006), participants have to correct error responses and stimulus stays on screen until response
is corrected. If latencies exceed a certain limit, a reminder to "respond more quickly" is optional in this script (see Editable Values for more info).

STIMULI:
- 21 words for Attribute Categories Good/Bad
- 7 words for target category (here: Animals)

SCORING:
Inquisit calculates d-scores using the improved scoring algorithm as described in Greenwald et al (2003). 
Only trials from test blocks count towards d-score calculation in this script.
Error trials are handled by requiring respondents to correct their responses according to recommendation Greenwald et al (2003, p.214).
This differs slightly from Karpinski & Steinman (2006) who removed noresponse trials from d-score calculations and 
replaced error responses with the block mean latency + 400ms error penalty.

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

/pretrialpause:							pause before stimuli presentation (default: 250ms)
/showreminder:							true = shows a reminder to respond faster if latencies exceeds a predetermined latency
														Note: Karpinsky & Steinman (2006) call using a reminder "largly window dressing" but that the response window (in this script: a pseudo response window) might create a "sense of urgency" (p.18)
										false = does not show reminder to respond more quickly (default in this script)
/reminderRT:							if response latency is larger than reminderRT, a reminder is presented to respond faster (if parameters.showreminder = true)
											Note: error responses have to be corrected in this script; this will add ms to their response latencies
/reminderduration:						time that the reminder to respond more quickly stays on the screen (default: 500ms)

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