Last Modified: January 17, 2023 by K. Borchert (katjab@millisecond.com), Millisecond
Script Copyright © Millisecond Software, LLC
This script implements a blocked Food Stroop by Millisecond. 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/accuracy differences to color-meaning congruent and color-meaning incongruent combinations. The Food Stroop takes advantage of this basic Stroop interference effect by comparing responses to food related words to color and neutral animal words.
5 minutes
Participants get words of 6 different conditions (e.g. unhealthy and healthy foods, animal names, and color words) in 4 different colors and are asked to press one of 4 keyboard keys as fast as possible.
1 Practice Block: 4 trials with "GREEN", "RED", "CAT", "BANANA"
6 Test Blocks: 6 x 12 trials tested in blocked* design by default
1) Congruent Color Words: presents 12 color words (red, blue, green, yellow) in the congruent color (3 repetitions of each color word with constraint that the same color cannot presented consecutively)
2) Incongruent Color Words: presents 12 color words (red, blue, green, yellow) in incongruent colors (3 repetitions of each color word; each time it is presented in a different incongruent color with constraint that the same color cannot presented consecutively)
3) unhealthy food choices: presents 12 unhealthy food choices in 4 colors (colors randomly selected with constraint that the same color cannot presented consecutively )
4) healthy food choices: presents 12 healthy food choices in 4 colors (colors randomly selected with constraint that the same color cannot presented consecutively )
5) animals (control for unhealthy food choices): presents 12 animals in 4 colors (colors randomly selected with constraint that the same color cannot presented consecutively)
6) animals (control for healthy food choices): presents 12 animals in 4 colors (colors randomly selected with constraint that the same color cannot presented consecutively)
- order of blocks is randomly selected
•blocked: the set-up of this script also allows to run the condition in a mixed design (without the constraint of repeated color selections)
Trial Sequence:
Fixation Cross for 200ms -> Stim word until verbal response (recorded but not evaluated)
see section Editable Stimuli
see section Editable Instructions
File Name: foodstroop_keyboardinput_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 |
| propCorrect | Overall proportion correct of test trials |
| meanRT | Overall mean correct latencies of test trials (in ms) + separate measures for each of the 6 experimental conditions cc:congruent color/word ic:incongruent color/word hpf (high calorie food) ntf (low calorie food) hpfa (animal comps for the high calorie food category), ntfa (animal comps for the low calorie food category) |
File Name: foodstroop_keyboardinput_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 |
| stimWord | Contains the current stim word |
| stimWordItemNumber | Stores the itemnumber of the current stimword |
| stimColor | Contains a numeric representation of the current word's display color 1=red, 2=green, 3=blue, 4=yellow |
| condition | Contains a numeric representation of the current condition 1=congruent color/word 2=incongruent color/word 3=HPF (high calorie food) 4=NTF (low calorie food) 5=HPFA (animal comps for the high calorie food category), 6=NTFA (animal comps for the low calorie food category) |
| 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 1=red, 2=green, 3=blue, 4=yellow |
| correct | The correctness of the response (1 = correct; 0 = incorrect) |
| latency | The response latency (in ms); measured from onset of word |
The procedure can be adjusted by setting the following parameters.
| Name | Description | Default |
|---|---|---|
Responsekey, Labels |
||
| keyRed | The red response button | 32 -> d |
| keyGreen | The green response button | 33 -> f |
| keyBlue | The blue response button | 36 -> j |
| keyYellow | The yellow response button | 37 -> k |
| getReadyDuration | The duration (in ms) of the get-ready-trial | 5000ms |