___________________________________________________________________________________________________________________ GENERIC DOT PROBE TASK - with word stimuli (top/bottom) Measure of Attentional Bias ___________________________________________________________________________________________________________________ Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC Date: 06-05-2015 last updated: 01-03-2025 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC Script Copyright © 01-03-2025 Millisecond Software ___________________________________________________________________________________________________________________ BACKGROUND INFO ___________________________________________________________________________________________________________________ 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) ___________________________________________________________________________________________________________________ TASK DESCRIPTION ___________________________________________________________________________________________________________________ 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. ___________________________________________________________________________________________________________________ DURATION ___________________________________________________________________________________________________________________ the default set-up of the script takes appr. 4 minutes to complete ___________________________________________________________________________________________________________________ DATA OUTPUT DICTIONARY ___________________________________________________________________________________________________________________ The fields in the data files are: (1) Raw data file: 'genericdotprobe_words_raw*.iqdat' (a separate file for each participant) build: The specific Inquisit version used (the 'build') that was run computer.platform: the platform the script was run on (win/mac/ios/android) date, time: date and time script was run subject, group: with the current subject/groupnumber session: with the current session id blockCode, blockNum: the name and number of the current block (built-in Inquisit variable) trialCode, trialNum: the name and number of the currently recorded trial (built-in Inquisit variable) Note: trialNum is a built-in Inquisit variable; it counts all trials run; even those that do not store data to the data file. 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 comp_x-probe_x: 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 (2) Summary data file: 'genericdotprobe_words_summary*.iqdat' (a separate file for each participant) inquisit.version: Inquisit version run computer.platform: the platform the script was run on (win/mac/ios/android) 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 completed: 0 = script was not completed (prematurely aborted); 1 = script was completed (all conditions run) NOTE: all latency/accuracy summary variables are based on correct responses with latencies >= parameters.minimum_latency (default: 100ms) 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 ___________________________________________________________________________________________________________________ EXPERIMENTAL SET-UP ___________________________________________________________________________________________________________________ 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 Note: 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) ___________________________________________________________________________________________________________________ STIMULI ___________________________________________________________________________________________________________________ generic text stimuli - insert your own under section Editable Stimuli stimuli are presented in white on a black background ___________________________________________________________________________________________________________________ INSTRUCTIONS ___________________________________________________________________________________________________________________ Original Instructions were generously shared by Dr. Fillmore. They have been slightly edited by Millisecond Software. They can be edited under section Editable Instructions. ___________________________________________________________________________________________________________________ INSTRUCTIONS TO ADD CATEGORIES ___________________________________________________________________________________________________________________ go to section INSTRUCTIONS HOW TO ADD ADDITIONAL CATEGORIES ___________________________________________________________________________________________________________________ EDITABLE CODE ___________________________________________________________________________________________________________________ check below for (relatively) easily editable parameters, stimuli, instructions etc. Keep in mind that you can use this script as a template and therefore always "mess" with the entire code to further customize your experiment. The parameters you can change are: /readyDuration: the duration (in ms) of the get-ready-trial (default: 3000ms) /fixationDuration:/targetduration: the duration of the fixation cross (default: 500ms)/the targets (default: 1000ms) /tpIsi: target-probe interstimulus interval in ms (0ms) /probeDuration: the duration of the probe presentation (default: 1000ms) Note: by default this scripts allows for responses for the entire probe duration; the trial terminates after parameters.probeduration is over /iti: intertrialpause in ms (default: 0ms) /probe: the symbol used for the probe (default: X) /responseKeyTop: the top response button (default: "T") /responseKeyBottom: the bottom response button (default: "B") /minimumLatency: the minimum latency of a correct response that is included into summary variables (default: 100ms) Physical Settings of Display: Note: change the settings to optimize the display on your computer screen /targetBottomY:-target_top_y: the y-coordinate in % of the top/bottom target (default: 35%, 65%) /targetX: the x-coordinate of the target (default: center at 50%) /fixationCrossHeight: the height of the fixation cross in canvas height percentage (default: 5%) /probeHeight: the height of the probe in canvas height percentage (default: 5%) /wordHeight: the height of the word in canvas height percentage (default: 5%)