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Unconscious Reward Task
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Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
last updated: 04-16-2024 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC
Millisecond Software thanks Dr. Eric Bijleveld for generously sharing his original e-prime script!
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BACKGROUND INFO
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This script implements the Unconscious Reward Task. Monetary rewards facilitate performance on cognitive tasks
even when these rewards are perceived without conscious awareness but differences in the speed-accuracy
only occur with consciously perceived rewards.
Reference:
Bijleveld, Custers, E.R. & Aarts, H. (2010). Unconscious reward cues increase invested effort,
but do not change speed–accuracy tradeoffs,Cognition, 115, 330-335,
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TASK DESCRIPTION
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Participants work on simple addition equations (3 + 2 + 6 = 13) and have to decide whether the suggested
solution is correct or incorrect. For correct evaluations, they can earn two types of rewards,
either a low reward (max. 1cent) or a high reward (max. 50cents) with the caveat that rewards get smaller
the longer is takes to respond.
The take-home reward further depends on the overall accuracy of the participants' responses: the extra money can
only be earned if 90% or more of all responses were correct.
Half the trials present the reward cues subliminally (at 17ms duration); half the trials present the reward cues
supraliminally (at 300ms).
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DURATION
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the default set-up of the script takes appr. 15-20 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: 'unconsciousrewardtask_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 such as feedback trials. Thus, trialnum
may not reflect the number of main trials run per block.
countTrials: counts the number of trials run
cueStim: 1 = selects the reward coin with itemnumber 1 (here: 1 cent)
2 = selects the reward coin with itemnumber 2 (here: 50 cents)
rewardValue: stores the value of the reward (here: 1 vs. 50)
cueDuration: stores the duration (in ms) of the reward cue (here: 17ms vs. 300ms)
mathProblem: contains the assembled math problem
corrSolution: the correct solution to the math problem
providedSolution: the computer suggested solution to the math problem
corrResponse: 1 = the suggested solution is correct;
0 = the suggested solution is incorrect
response: the participant's response: scancode of response key
18 = E ('correct')
23 = I ('incorrect')
resp: 1 = the suggested solution is accepted as correct;
0 = the suggested solution is not accepted as correct
correct: accuracy of response: 1 = correct response (participant selected correct response key); 0 = otherwise
latency: the response latency (in ms); measured from: onset of math problem until response
rewardAmount: the calculated earned reward amount for the current trial
totalRewardAmount: the cumulative reward amounts
takeHomeReward: the take home reward (depends on performance (90% correct or higher) and totalRewardAmount)
(2) Summary data file: 'unconsciousrewardtask_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)
propCorrect_overall: proportion correct responses across all 56 trials
totalRewardAmount: the cumulative reward amounts
takeHomeReward: the take home reward (depends on performance (90% correct or higher) and totalRewardAmount)
propCorrect_reward1duration1: proportion correct responses for reward 1 (here: 1cent) presented for the short (superliminal) duration (here: 17ms)
meanRT_reward1duration1: mean response time (in ms) of correct responses for reward 1 (here: 1cent) presented for the short duration (here: 17ms)
that were < 7000ms (at 7000ms and above no reward can be earned)
propCorrect_reward1duration2: proportion correct responses for reward 1 (here: 1cent) presented for the long (supraliminal) duration (here: 300ms)
meanRT_reward1duration2: mean response time (in ms) of correct responses for reward 1 (here: 1cent) presented for the long duration (here: 300ms)
that were < 7000ms (at 7000ms and above no reward can be earned)
propCorrect_reward2duration1: proportion correct responses for reward 2 (here: 50cents) presented for the short (superliminal) duration (here: 17ms)
meanRT_reward2duration1: mean response time (in ms) of correct responses for reward 2 (here: 50cents) presented for the short duration (here: 17ms)
that were < 7000ms (at 7000ms and above no reward can be earned)
propCorrect_reward2duration2: proportion correct responses for reward 2 (here: 50cents) presented for the long (supraliminal) duration (here: 300ms)
meanRT_reward2duration2: mean response time (in ms) of correct responses for reward 2 (here: 50cents) presented for the long duration (here: 300ms)
that were < 7000ms (at 7000ms and above no reward can be earned)
* 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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Test: 56 trials
- 28 trials with reward 1 (14 presented at 17ms (7 correct), 14 presented at 300ms (7 correct));
28 trials with reward 2 (14 presented at 14 ms (7 correct), 14 presented at 300ms (7 correct))
- trial order is random
- the math problem is randomly (without replacement) selected from the pool of pre-generated 56 problems
Trial Sequence:
-> precue fixation (3000ms)
-> precue mask (400ms)
-> cue (17ms vs. 300ms)
-> postcue mask (583ms vs. 300ms)
-> postcue fixation (1500ms)
-> generic equation cue (1500ms): 'x+x+x=xx'
-> math equation (until response): actual problem presented
-> performance feedback (3000ms): participants learn whether a) they were correct or incorrect and b) how much they earned
-> cumulative earnings feedback (2000ms): participants learn their accumulated earnings
-> iti
(one break after 28 trials)
Reward Calculations: the promised reward decreases by ~14% per s responding
- the rewards per trial (for correct responses) are calculated using the following formula:
actual reward = max. rewardvalue - (max. rewardValue * response time in ms/7000)
=> responses given after 7000ms earn an actual reward value of 0 (same as incorrect responses)
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STIMULI
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* 56 addition problems generously provided by Dr. Eric Bijleveld (see section Editable Stimuli)
- each problem contains 3 digits (1-9) (repeated digits ok)
- no two of the digits add up to 10
* coins and mask generously provided by Dr. Eric Bijleveld (see section Editable Stimuli)
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INSTRUCTIONS
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generously provided by Dr. Eric Bijleveld and translated to English by Millisecond Software
(see section Editable Instructions)
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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:
/pauseTrial: a rest trial is presented after 28 (default) trials
Duration Parameters:
/readyDuration: the duration (in ms) of the 'get-ready' trial (default: 3000ms)
/precue_fixationDuration: the duration (in ms) of the precue fixation cross (default: 3000ms)
/premaskDuration: the duration (in ms) of the precue mask (default: 400ms)
/shortcueDuration: the duration (in ms) of the short reward cue (default: 17ms)
/longcueDuration: the duration (in ms) of the long reward cue (default: 300ms)
/combinedCueMaskDuration: the duration (in ms) of the combined cue and postcue mask (default: 600ms)
Note: the post-cue mask will be longer for the short cue duration
/postcue_fixationDuration: the duration (in ms) of the postcue fixation cross (default: 1500ms)
/genericEquationCueDuration: the duration (in ms) of the (X+X+X=XX) stimulus before actual math problem is presented (default: 1500ms)
/performanceFeedbackDuration: the duration (in ms) of the performance feedback (default: 3000ms)
/earningFeedbackDuration: the duration (in ms) of the total earnings feedback (default: 2000ms)
/iti: the duration (in ms) of the intertrial interval (default: 3000ms)
/pauseDuration: the duration (in ms) of the rest/pause trial (default: 10000ms)
Stimulus Sizing Parameters:
/cueSize: the proportional (to canvas) size of the reward cue (default: 30%)
/fixationSize: the proportional (to canvas) size of the fixation cross (default: 8%)
/problemSize: the proportional (to canvas) size of the math problem (default: 5%)
Response Key Assignment:
/leftResponseKey: the left response key label (here: E)
/rightResponseKey: the right response key label (here: I)
/correctResponseKey: the correct response key label (here: the left response key)
/incorrectResponseKey: the correct response key label (here: the right response key)
