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ABCD Game of Dice Task (GDT)
(smartphone version)
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Script Author: David Nitz (dave@millisecond.com) for Millisecond Software LLC for Millisecond Software, LLC
last updated: 02-22-2022 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC
Script Copyright © 02-22-2022 Millisecond Software
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BACKGROUND INFO
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This script implements the 'Game of Dice Task' (GDT), a test of risky gambling decisions,
with and without feedback (optional).
The script was customized for the ABCD Research Consortium and is generously shared via the
Millisecond Software library. This script has been optimized for smartphones (remote testing).
A version for tablets (in person testing) is also available.
The implemented procedure is based on:
(with feedback):
Brand, M., Fujiwara, E., Borsutzky, S., Kalbe, E., Kessler, J., & Markowitsch, H.J. (2005).
Decision-making deficits of Korsakoff patients in a new gambling task with explicit rules -
associations with executive functions. Neuropsychology, 19, 267–277.
and
(without feedback)
Brand, M. (2008). Does the feedback from previous trials influence current decisions? A study on the role
of feedback processing in making decisions under explicit risk conditions.
Journal of Neuropsychology, 2, 431-443.
By default the script plays the version WITH feedback. To play the version WITHOUT feedback, go to
Editable Task Parameters -> parameters.GDTversion and change to parameters.GDTversion = 2.
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TASK DESCRIPTION
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A dice is being rolled and participants have to bet on the outcome.
They have the choice between 4 different kinds of bets:
- a single bet (betting on a specific dice face: earns the most money if correct, but loses the most if incorrect (very risky bet)
- a dual bet (betting on two possible dice faces: if either one of them is rolled, it's a win. earns/loses slightly less than single bet (risky bet)
- a triple bet (betting on three possible dice faces: earns/loses less than dual bet (safe bet)
- a quadruple bet (betting on four possible dice faces: ears/loses the least (safest bet)
Participants can quit at any point before the default rounds (18) are played.
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DURATION
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the default set-up of the script takes appr. 5 minutes to complete
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DATA FILE INFORMATION
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The default data stored in the data files are:
(1) Raw data file: 'abcdgameofdicetask_smartphone_raw*.iqdat' (a separate file for each participant)*
build: Inquisit build
computer.platform: the platform the script was run on (win/mac/ios/android)
information about the current screen size:
screenWidth_inmm
screenHeight_inmm
date, time, subject, group, session: date and time script was run with the current subject/groupnumber/session number
GDTversion: 1 = original version with feedback (default); 2 = version without feedback
blockcode, blocknum: the name and number of the current block
phase: "practice" vs. "test"
currentround: stores the current round number (resets after practice)
trialcode, trialnum: the name and number of the currently recorded trial
(Note: not all trials that are run might record data, but trialnum still counts them)
latency: the response latency (in ms)
chosen: the selected dice faces participants is betting on (example: "1", "12", "123", "1234")
throw: the dice face thrown
row: reflects participant's betting choice:
For "singles" ("1", "2", etc.) values.row = 1
For "doubles" ("12", "34", etc.) values.row = 2
For "triples" ("123", "456") values.row =3
For "quadruples" ("1234", etc.) values.row = 4
currentbet: the amount of money currently bet on values.chosen
gain: amount of money won or lost in the current round (e.g. -500)
account_balance: Amount participant owns
single: counts how many times participant has bet on 1 specific dice face
double: counts how many times participant has bet on 2 possible dice faces
triple: counts how many times participant has bet on 3 possible dice faces
quadruple: counts how many times participant has bet on 4 possible dice faces
safe: counts how many times participants selected a safe bet (bets on 3 or 4 dice faces)
risky: counts how many times participants selected a risky bet (bets on 1 or 2 dice faces)
net_score: reflects the number of safe (bets on 3 or 4 numbers) vs. risky (bets
on 1 or 2 numbers) choices. It is computed as number of safe bets minus number of risky bets.
wins: adds the number of winning bets
losses: adds the number of losing bets
(2) Summary data file: 'abcdgameofdicetask_smartphone_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)
information about the current screen size:
screenWidth_inmm
screenHeight_inmm
GDTversion: 1 = original version with feedback (default); 2 = version without feedback
account_balance: amount participant owns at the end
single: counts how many times participant has bet on 1 specific dice face
double: counts how many times participant has bet on 2 possible dice faces
triple: counts how many times participant has bet on 3 possible dice faces
quadruple: counts how many times participant has bet on 4 possible dice faces
safe: counts how many times participants selected a safe bet (bets on 3 or 4 dice faces)
risky: counts how many times participants selected a risky bet (bets on 1 or 2 dice faces)
net_score: reflects the number of safe (bets on 3 or 4 numbers) vs. risky (bets
on 1 or 2 numbers) choices. It is computed as number of safe bets minus number of risky bets.
wins: adds the number of winning bets
losses: adds the number of losing bets
* separate data files: to change to one data file for all participants (on Inquisit Lab only), go to section
"DATA" and follow further instructions
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EXPERIMENTAL SET-UP
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* one-trial for practice (does not count towards summary statistics)
* by default max. 18 rounds get played (set under section Editable Parameters)
* participant can quit at any point
* the faces are selected randomly without replacement from list.rolldice
* by default, participant get feedback of the dice throw and updating of account information
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INSTRUCTIONS
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Revised instructions, visuals and other procedural details thanks to the helpful and generous input
from the original authors.
verbal instructions made available by the ABCD Research Consortium
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EDITABLE CODE
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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:
GDTversion: 1 = original version with feedback (default);
2 = version without feedback
Note: adjust instructions accordingly under section Editable Instructions
nrounds_gdt: Number of rounds in feedback version (must be a multiple of 6); default is 18
nrounds_gdt_nf: Number of rounds in no-feedback version (must be a multiple of 6); default is 18
IMPORTANT: When in- or decreasing the number of rounds in either version, adjust
the number of items in list.rolldice accordingly.
account_balanceStart: Amount of points / Money at Task Onset
currency: Exchange "$" with "€", "£", "¥", etc.
gainsingle: Amount to be won/lost when betting on a single number (e.g. "3")
gaindouble: Amount to be won/lost when betting on a combination of two numbers (e.g. "5 or 6")
gaintriple: Amount to be won/lost when betting on a combination of three numbers (e.g. "1 or 2 or 3")
gainquadruple: Amount to be won/lost when betting on a combination of four numbers (e.g. "2 or 3 or 4 or 5")
showquitbutton: true: the quit button is visibly presented during each trial
false (default): the quit button is invisible
/scriptlastupdate: should store the date of the last change made to the script
