Emotional Stroop Task With Keyboard Responses

Technical Manual

Last Modified: January 18, 2025 by K. Borchert (katjab@millisecond.com), Millisecond

Script Copyright © Millisecond Software, LLC

Background

This script implements an Aggression Themed Emotional Stroop task. The classic Stroop paradigm demonstrates the interference of word meaning on naming the color in which the words are written as measured by reaction time differences to color-meaning congruent and color-meaning incongruent combinations. The Aggression Stroop takes advantage of this basic Stroop interference effect by comparing reaction times to aggression related words, positive and negative words and neutral words.

The implemented procedure is based on:

Smith, P. & Waterman, M. (2003). Processing bias for aggression words in forensic and nonforensic samples. Cognition and Emotion, 17, 681-701.

This script uses keyboard input instead of voice recordings.

Duration

5 minutes

Description

Participants are presented words from 5 different categories (aggression, neutral, positive, negative, color word) in four different colors (blue, red, yellow, green) and are asked to press one of four response keys to indicate the color of the words regardless of their meaning.

Procedure

1. Practice Block: 10 trials (not original; this script uses the words "one" to "ten" as practice stimuli)
2. Test Block: 125 trials (= 5 categories x 25 trials); trials are randomly sampled
without replacement
• error feedback given; to remove follow instructions under section TRIALS

Stimuli

• original stimuli by Smith & Waterman (2003)
(due to a potential typo in the original article one word appeared
under two categories (Appendix2); we replaced it with a word that is similar in length and appearance
=> section Editable STIMULI-> Negative Words)

• each color appears 6 times in each category (the 7th pairing of word-color is random)
• color words "red", "yellow", "blue" and "green" are not used as targets
• 5 color words are repeats (see Smith & Waterman, 2003)

Instructions

Instructions are not original to the task. They are provided by Millisecond
and can be edited in script "emotionalstroopwithkeyboardinput_instructions_inc.iqjs"

Summary Data

File Name: emotionalstroopwithkeytboardinput_summary*.iqdat

Data Fields

NameDescription
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
propCorrectPos Proportion correct for all 5 categories
meanrtNeu-
meanrtPos Mean latencies for correct responses for all 5 categories separately
biasAgg-
biasPos Bias Scores: Difference between mean latency in categories Aggression, Color, Positive Words, Negative Words
and Neutral Word condition (category mean latencies are subtracted from mean latency of Neutral condition)
=> positive scores: meaning of category words interfered more than meaning of neutral words on color categorization task

Raw Data

File Name: emotionalstroopwithkeytboardinput_raw*.iqdat

Data Fields

NameDescription
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
target The currently selected target word
color The currently selected color
response The participant's key response (scancode of response button)
scancode/label for the red response button (default: 32 -> d)
scancode/label for the green response button (default: 33 -> f)
scancode/label for the blue response button (default: 36 -> j)
scancode/label for the yellow response button (default: 37 -> k)
responseCategory The interpreted key response
"red"
"green"
"blue"
"yellow"
correct The correctness of the response (1 = correct; 0 = incorrect)
latency The response latency (in ms); measured from onset of word

Parameters

The procedure can be adjusted by setting the following parameters.

NameDescriptionDefault
fixationCrossPresentationTime Time (in ms) that fixation cross is presented 500ms
keyRed The red response button d
keyGreen The green response button f
keyBlue The blue response button j
keyYellow The yellow response button k