Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond
Created: January 05, 2015
Last Modified: January 03, 2025 by K. Borchert (katjab@millisecond.com), Millisecond
Script Copyright © Millisecond Software, LLC
This script implements a dotprobe procedure to measure attentional bias with word stimuli. The implemented procedure is based on:
Miller, M.A. & Fillmore, M.T (2010). The effect of word complexity on attentional bias towards alcohol-related words in adult drinkers. Addiction, 105, 883–890.
Note: this dot probe runs with words instead of images and the stimuli are presented on top and bottom of the fixation cross (instead of to the left and right)
4 minutes
After presentation of a fixation cross in the center of the screen, participants are presented with 2 words. The position of the words is randomly chosen to be either bottom or top to the location of the fixation cross. After a short duration, the two words disappear and a probe stimulus (here: X) appears in the location of one of the texts. Participants are asked to press one key if the probe is on the bottom and another if the probe is on top.
2 categories tested; within-design
- 1 block of 10 practice trials
- 1 block of 80 trials: 40 category1 trials (category1target-category2comp pairings) and 40 category2 pairings
10 word pairs, all texts presented 4 times
category1:
=> top/bottom, followed by prime/not followed by prime => 10 * 4 = 40 trials
category2: the same
all 80 trials are randomly sampled without replacement
DEFAULT TRIAL SEQUENCES
fixation cross (500ms) -> target word pair (1000ms) -> tpIsi (0ms) -> probe (max. 1000ms) (latency measured from onset of probe until response or offset of probe; whichever comes first)
generic text stimuli - insert your own under section Editable Stimuli
stimuli are presented in white on a black background
Original Instructions were generously shared by Dr. Fillmore.
They have been slightly edited by Millisecond.
They can be edited under section Editable Instructions.
go to section INSTRUCTIONS HOW TO ADD ADDITIONAL CATEGORIES
File Name: genericdotprobe_words_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 | Proportion correct overall |
| meanRT | Overall mean latency (in ms) |
| propCorrectCongruentCategory1 | Proportion correct in congruent Category1 trials |
| meanrtCongruentCategory1 | Mean latency of congruent Category1 trials |
| propCorrectIncongruentCategory1 | Proportion correct in incongruent Category1 trials |
| meanrtIncongruentCategory1 | Mean latency of incongruent Category1 trials |
| abCategory1 | Attentional Bias for Category1 words : If AB_Category1 > 0 => faster mean latencies to congruent Category1 trials than incongruent ones |
| propCorrectCongruentCategory2 | Proportion correct in congruent Category2 trials |
| meanrtCongruentCategory2 | Mean latency of congruent Category2 trials |
| propCorrectIncongruentCategory2 | Proportion correct in incongruent Category2 trials |
| meanrtIncongruentCategory2 | Mean latency of incongruent Category2 trials |
| abCategory2 | Attentional Bias for Category2 words ('targets'): If AB_Category2 > 0 => faster mean latencies to congruent Category2 trials than incongruent ones |
File Name: genericdotprobe_words_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 |
| task | 1 = practice; 2 = test |
| category | 1 = category1 ; 2 = category2 |
| congruence | 1 = probe and target (e.g. category1) position same; 2 = probe and target (e.g. category1) position different |
| targetPosition | 1 = target (e.g. category1) word on left; 2 = target (e.g. category1) word on right |
| compX-probeX | The x-coordinate (in %) of the target (e.g. category1)/ comp ('paired with target') /probe stims |
| itemNumber | Itemnumber of currently selected word |
| targetWord | Stores the currently presented target (e.g. category1) word |
| compWord | Stores the currently presented comp ('paired with target') word |
| response | The participant's response (scancode of response button) 49 = N (left key) 50 = M (right key) |
| latency | The response latency in ms (measured from onset of probe) |
| correct | Accuracy of response (regardless of whether latency >= parameters.minimum_latency) 1 = correct; 0 = incorrect |
| valid | Latency in ms that is >= parameters.minimum_latency |
| validCorrect | 1 = response was correct AND latency was >= parameters.minimum_latency; 0 = otherwise |
The procedure can be adjusted by setting the following parameters.
| Name | Description | Default |
|---|---|---|
| readyDuration | The duration (in ms) of the get-ready-trial | 3000ms |
| fixationDuration, targetduration | The duration of the fixation cross /the targets (default: 1000ms) | 500ms |
| tpIsi | Target-probe interstimulus interval in ms (0ms) | |
| probeDuration | The duration of the probe presentation by default this scripts allows for responses for the entire probe duration the trial terminates after parameters.probeduration is over | 1000ms |
| iti | Intertrialpause in ms | 0ms |
| probe | The symbol used for the probe | X |
| responseKeyTop | The top response button | "T" |
| responseKeyBottom | The bottom response button | "B" |
| minimumLatency | The minimum latency of a correct response that is included into summary variables (default: 100ms) Physical Settings of Display: change the settings to optimize the display on your computer screen | |
| targetBottomY, targetTopY | The y-coordinate in % of the top/bottom target | 35%, 65% |
| targetX | The x-coordinate of the target | center at 50% |
| fixationCrossHeight | The height of the fixation cross in canvas height percentage | 5% |
| probeHeight | The height of the probe in canvas height percentage | 5% |
| wordHeight | The height of the word in canvas height percentage | 5% |