Script Author: Jan De Houwer
Credits:
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.
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: June 29, 2026 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.
see section Editable Stimuli in script 'standardeast_stimuli_inc.iqjs'
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.
They can be edited in script 'standardeast_instructions_inc.iqjs'
File Name: standardeast_summary*.iqdat
| Name | Description |
|---|---|
| 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 |
| inquisit.version | Inquisit version number |
| computer.platform | Device platform: win | mac |ios | android |
| computer.touch | 0 = device has no touchscreen capabilities; 1 = device has touchscreen capabilities |
| computer.hasKeyboard | 0 = no external keyboard detected; 1 = external keyboard detected |
| completed | 0 = Test was not completed 1 = Test was completed |
Summary Variables Added By Millisecond |
|
| 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) |
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 log10 is used in this script |
| 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 |
|
| 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 |
|---|---|
| date | Date the session was run |
| time | Time the session was run |
| subject | Participant ID |
| group | Group number |
| session | Session number |
| build | Inquisit version number |
| computer.platform | Device platform: win | mac |ios | android |
| computer.touch | 0 = device has no touchscreen capabilities; 1 = device has touchscreen capabilities |
| computer.hasKeyboard | 0 = no external keyboard detected; 1 = external keyboard detected |
| blockcode | The name the current block (built-in Inquisit variable) |
| blocknum | The number of the current block (built-in Inquisit variable) |
| trialcode | The name of the currently recorded trial (built-in Inquisit variable) |
| trialnum | The number of the currently recorded trial (built-in Inquisit variable) trialnum is a built-in Inquisit variable; it counts all trials run even those that do not store data to the data file. |
| 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') |
| responseText | The response key label |
| 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 |
|---|---|---|
Timing Parameters |
||
| pretrialPause | Pretrialpause in ms (blank screen) before new trial starts | 0 |
| posttrialPause | Posttrialpauses in ms | 200 |
| fixationDuration | Duration (in ms) of fixation cross | 350 |
| getReadyDuration | Duration (in ms) of get-ready trial | 5000 |
For Calculation Of Summary East Scores: Latencies Should Be Within 300Ms < Latency < 3000Ms (See Dehouwer, 2003, P.81) |
||
| minRT | The minimum latency that should not be recoded | 300 |
| maxRT | The maximum latency that should not be recoded | 3000 |