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*STANDARD EXTRINSIC AFFECTIVE SIMON TASK (EAST)*
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Script Author: Jan De Houwer
last updated: 02-28-2022 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC
Millisecond Software thanks Dr. De Houwer for sharing his original script!
Millisecond Software is responsible for adding the USER MANUAL and the summary variables as well as for
renaming the trials and target categories and editing the instructions.
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BACKGROUND INFO
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This script implements the Extrinsic Affective Simon Task. The Extrinsic Affective Simon Task
is a test of implicit attitude that allows to estimate the attitude towards
target categories by comparing the time needed to make assigned 'positive' vs. assigned
'negative' responses.
In general, the EAST tests participants with attribute trials (trials with stimuli of
either positive or negative valence) that define the nature of 'good' and 'bad' response keys.
The correct response key for negative items is the 'bad' response key.
The correct response key for positive items is the 'good' response key.
Intermixed with these attribute trials are target trials that present targets of
2 different categories that present the target words in color.
Blue-green target words (regardless of target category) get assigned the 'good' target key as the correct response;
green-blue target words (regardless of target category) get assigned the 'bad' target key as the correct response
(The color assignment to good/bad keys is counterbalanced by groupnumber).
Differences in reaction time to categorize items of the same target category correctly with the 'good' and 'bad'
response keys (depending on their color) are used to calculate EAST scores separately for each target category.
Latencies of trials that required the positive key are subtracted from latencies that require the negative key.
Positive EAST scores indicate that participants were faster to categorize items of the same category with
the positive than with the negative response keys and thus positive EAST scores are interpreted to indicate
a positive attitude towards that category. Negative EAST scores suggest the opposite.
This template script runs target category 1 as 'positive words' and target category 2 as 'negative words'.
The target categories can easily be exchanged under section EDITABLE STIMULI.
Note that the EAST estimates scores separately for each target category and thus could be run with only
one category instead of two as done in this script.
Reference:
De Houwer, J. (2003). The Extrinsic Affective Simon Task. Experimental Psychology, 50, 77-85.
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TASK DESCRIPTION
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Participants are presented white, blue, and green words of either positive or negative valence.
Participants are asked to categorize the white words (=attribute trials) into good key ('P')
or bad Key ('Q') categories based on their meaning while at the same time they are asked to categorize blue
and green words (=target trials of category1 and category2) into the same good key ('P') or bad Key ('Q')
categories simply based on their arbitrary color (half the participants categorize blue words as good and
green as bad).
Note: the 'categories' tested in this template script are positive and negative words. However,
you can easily use different target categories. Go to EDITABLE STIMULI for further instructions.
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DURATION
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the default set-up of the script takes appr. 10 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: 'standardeast_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
session: 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. Thus, trialnum
may not reflect the number of main trials run per block.
ObjectCategory: "negative attribute" = white negative words
"positive attribute" = white positive words
"Category 1" = positive target words displayed in color (could be replaced by a different target category, e.g. flowers)
"Category 2" = negative target words displayed in color (could be replaced by a different target category, e.g. insects)
ResponseKeyCategory: "good" (=P key is correct response) vs. "bad" (=Q key is correct response)
stimulusitem.1: fixation cross
stimulusitem.2: the presented target word
response: the participant's response (scancode of response key)
16 = Q ('bad')
25 = P ('good')
correct: the correctness of the response (1 = correct; 0 = incorrect)
latency: the response latency (in ms) from onset of words
(2) Summary data file: 'standardeast_summary*.iqdat' (a separate file for each participant)
inquisit.version: Inquisit version run
computer.platform: the platform the script was run on (win/mac/ios/android)
startDate: date script was run
startTime: time script was started
subjectid: assigned subject id number
groupid: assigned group id number
sessionid: assigned session id number
elapsedTime: time it took to run script (in ms); measured from onset to offset of script
completed: 0 = script was not completed (prematurely aborted);
1 = script was completed (all conditions run)
Summary Variables added by Millisecond Software:
propError: overall proportion of incorrect categorizations in test trials
meanRT: overal mean latency (in ms) of correct categorizations in test trials
Note: latencies are uncorrected (no recoding of latencies that fall outside permitted range)
Note: the following latencies are corrected/recoded, so that all latencies are in permitted range
parameters.minRT < latency < parameters.maxRT (see DeHouwer 2003, p.81)
Note: Category1: here = positive target words displayed in color
propError_cat1_neg: proportion error categorizations of category1 words with negative response key
meanCorrRT_cat1_neg: mean correct latency (in ms) of categorizing category1 words with negative response key
meanCorrLogRT_cat1_neg: log-transformed mean correct latency (in ms) of categorizing category1 words with negative response key
propError_cat1_pos: proportion error categorizations of category1 words with positive response key
meanCorrRT_cat1_pos: mean correct latency (in ms) of categorizing category1 words with positive response key
meanCorrLogRT_cat1_pos: log-transformed mean correct latency (in ms) of categorizing category1 words with positive response key
Note: Category2: here = negative target words displayed in color
propError_cat2_neg: proportion error categorizations of category2 words with negative response key
meanCorrRT_cat2_neg: mean correct latency (in ms) of categorizing category2 words with negative response key
meanCorrLogRT_cat2_neg: log-transformed mean correct latency (in ms) of categorizing category2 words with negative response key
propError_cat2_pos: proportion error categorizations of category2 words with positive response key
meanCorrRT_cat2_pos: mean correct latency (in ms) of categorizing category2 words with positive response key
meanCorrLogRT_cat2_pos: log-transformed mean correct latency (in ms) of categorizing category2 words with positive response key
EAST scores are calculated separately for Category1 ('positive target words') and Category2 ('negative target words' )
words "by deducting the mean log transformed reaction time and percentage of errors on trials with an extrinsically
positive response from the mean log-transformed reaction time and percentage of errors on trials with an
extrinsically negative response. A positive EAST score thus signifies a positive attitude" (see DeHouwer 2003, p.81).
EAST_ERRORscore_Cat1: based on errors for Category 1 (here: positive target words)
EAST_RTscore_Cat1: based on log-transformed latencies for Category 1
EAST_ERRORscore_Cat2: based on errors for Category 2 (here: negative target words)
EAST_RTscore_Cat2: based on log-transformed latencies for Category 2
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EXPERIMENTAL SET-UP
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Practice:
1 Practice block categorizing white stimuli only - 20 trials (10 positive; 10 negative => 2 repetitions of stims)
1 Practice block categorizing blue/green words - 20 trials (5 positive green, 5 positive blue, 5 negative green, 5 negative blue)
Test:
3 Testblocks: mixed white words and colored words - 30 trials each (5 positive white, 5 negative white, 5 positive green, 5 positive blue, 5 negative green, 5 negative blue)
General Trial Sequence:
-> Pretrialpause (1000ms)
-> * (for 21 vertical frames: on a 60Hz monitor ~357ms)
-> WORD until response (either correct or incorrect): words selected in random order
-> Errorfeedback (400ms)
-> Posttrialpause (200ms)
Note: blue/green assignment to good key/bad key is counterbalanced by groupnumber.
odd groupnumbers: blue -> positive key; green -> negative key
even groupnumbers: blue -> negative key; green -> positive key
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STIMULI
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see section Editable Stimuli
Note:
in this template script the tested target categories are:
Category 1: positive words
Category 2: negative words
The target category and target words can easily be changed under section EDITABLE STIMULI
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INSTRUCTIONS
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Instructions are based on the original ones but were adapted to hmtl pages by Millisecond Software.
Instructions can be edited by changing the provided htm/html files directly.
To edit htm/html-files: open the respective documents in simple Text Editors such as TextEdit (Mac)
or Notepad (Windows).
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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:
/pretrialpause: pretrialpauses in ms (default: 1000ms)
/posttrialpause: posttrialpauses in ms (default: 200ms)
/getReadyDuration: duration (in ms) of get-ready trial
For Calculation of Summary EAST Scores: latencies should be within 300ms < latency < 3000ms (see DeHouwer, 2003, p.81)
If they are above or below, they should be recoded
/minRT: the minimum latency that should not be recoded (default: 300ms)
/maxRT: the maximum latency that should not be recoded (default: 3000ms)
