Script Author: Jan De Houwer
Millisecond thanks Dr. De Houwer for sharing his original script!
Millisecond 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.
Last Modified: January 07, 2025 by K. Borchert (katjab@millisecond.com), Millisecond
Script Copyright © Millisecond Software, LLC
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.
De Houwer, J. (2003). The Extrinsic Affective Simon Task. Experimental Psychology, 50, 77-85.
10 minutes
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).
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.
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)
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
see section Editable Stimuli
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
Instructions are based on the original ones but were adapted to hmtl pages by Millisecond.
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).
File Name: standardeast_summary*.iqdat
| Name | Description |
|---|---|
| inquisit.version | Inquisit version number |
| computer.platform | Device platform: win | mac |ios | android |
| startDate | Date the session was run |
| startTime | Time the session was run |
| subjectId | Participant ID |
| groupId | Group number |
| sessionId | Session number |
| elapsedTime | Session duration in ms |
| completed | 0 = Test was not completed 1 = Test was completed |
| propError | Overall proportion of incorrect categorizations in test trials |
| meanRT | Overal mean latency (in ms) of correct categorizations in test trials latencies are uncorrected (no recoding of latencies that fall outside permitted range) the following latencies are corrected/recoded, so that all latencies are in permitted range parameters.minRT < latency < parameters.maxRT (see DeHouwer 2003, p.81) Category1: here = positive target words displayed in color |
| propErrorCat1Neg | Proportion error categorizations of category1 words with negative response key |
| meanCorrRTCat1Neg | Mean correct latency (in ms) of categorizing category1 words with negative response key |
| meanCorrLogRTCat1Neg | Log-transformed mean correct latency (in ms) of categorizing category1 words with negative response key |
| propErrorCat1Pos | Proportion error categorizations of category1 words with positive response key |
| meanCorrRTCat1Pos | Mean correct latency (in ms) of categorizing category1 words with positive response key |
| meanCorrLogRTCat1Pos | Log-transformed mean correct latency (in ms) of categorizing category1 words with positive response key Category2: here = negative target words displayed in color |
| propErrorCat2Neg | Proportion error categorizations of category2 words with negative response key |
| meanCorrRTCat2Neg | Mean correct latency (in ms) of categorizing category2 words with negative response key |
| meanCorrLogRTCat2Neg | Log-transformed mean correct latency (in ms) of categorizing category2 words with negative response key |
| propErrorCat2Pos | Proportion error categorizations of category2 words with positive response key |
| meanCorrRTCat2Pos | Mean correct latency (in ms) of categorizing category2 words with positive response key |
| meanCorrLogRTCat2Pos | 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). |
| eastErrorScoreCat1 | Based on errors for Category 1 (here: positive target words) |
| eastRTScoreCat1 | Based on log-transformed latencies for Category 1 |
| eastErrorScoreCat2 | Based on errors for Category 2 (here: negative target words) |
| eastRTScoreCat2 | Based on log-transformed latencies for Category 2 |
File Name: standardeast_raw*.iqdat
| Name | Description |
|---|---|
| build | Inquisit version number |
| computer.platform | Device platform: win | mac |ios | android |
| date | Date the session was run |
| time | Time the session was run |
| subject | Participant ID |
| group | Group number |
| session | Session number |
| blockCode | Name of the current block |
| blockNum | Number of the current block |
| trialCode | Name of the current trial |
| trialNum | Number of the current trial |
| 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 |
The procedure can be adjusted by setting the following parameters.
| Name | Description | Default |
|---|---|---|
| pretrialPause | Pretrialpauses in ms | 1000ms |
| posttrialPause | Posttrialpauses in ms | 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 | 300ms |
| maxRT | The maximum latency that should not be recoded | 3000ms |