___________________________________________________________________________________________________________________ MONETARY INCENTIVE DELAY TASK ___________________________________________________________________________________________________________________ Script Author: Katja Borchert, Ph.D. (email@example.com) for Millisecond Software, LLC Date: 08-28-2015 last updated: 02-25-2022 by K. Borchert (firstname.lastname@example.org) for Millisecond Software, LLC Script Copyright © 02-25-2022 Millisecond Software ___________________________________________________________________________________________________________________ BACKGROUND INFO ___________________________________________________________________________________________________________________ This script implements the Monetary Incentive Delay Task; a task to induce anticipation of reward and punishment within a simple reaction time task. The implemented procedure is based on: Knutson, B., Westdorp, A., Kaiser, E., & Hommer, D. (2000). FMRI visualization of brain activity during a monetary incentive delay task. Neuroimage, 12(1), 20-27 ___________________________________________________________________________________________________________________ TASK DESCRIPTION ___________________________________________________________________________________________________________________ Participants are asked to respond to a brief target shape that follows 2 different cues: one an incentive cue (e.g. an orange shape) and the other a nonincentive cue (e.g. a blue shape). Responses to nonincentive targets (aka targets following nonincentive cues) never have an impact on money gained or money lost; nevertheless participants receive verbal feedback whether they were fast enough or not. Responses to incentive targets have different consequences depending on three different reward conditions: Control vs. Reward vs. Punishment. In the Reward condition, participants who respond fast enough to a target that follows an incentive cue get a monetary reward (e.g. $1). If they are not fast enough, no money is won. In the Punishment condition, participants who respond fast enough to a target that follows an incentive cue do not lose any money (e.g. $1). If they fail to respond in time, they lose money (e.g. $1). In the control condition, there is no difference between incentive and nonincentive targets. Participants can neither win any money, nor can they lose any. ___________________________________________________________________________________________________________________ DURATION ___________________________________________________________________________________________________________________ the default set-up of the script takes appr. 30 minutes to complete ___________________________________________________________________________________________________________________ DATA FILE INFORMATION ___________________________________________________________________________________________________________________ The default data stored in the data files are: (1) Raw data file: 'monetaryincentivedelaytask_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. exp_condition: 0 = control condition; 1 = Reward condition; 2 = Punishment Condition order: 'reward->punish' vs. 'punish->reward' incentive_condition: 1 = incentive; 2 = nonincentive delayduration: the current delay duration in ms targetduration: the current target duration in ms (also the response window) baselineRT60: the 60th percentile reaction time (in ms) based on mean and standard deviation: X = z-score(60th percentile)*SD + mean stimulusitem: the presented stimuli in order of trial presentation (only static elements) response: the participant's response (here: scancode of response button) correct: the correctness of the response (1 = correct; 0 = incorrect) latency: the response latency (in ms) total_control: the total earned in control condition total_reward: the total earned in reward condition total_punishment: the total earned in punishment condition (2) Summary data file: 'monetaryincentivedelaytask_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) order: 'reward->punish' vs. 'punish->reward' meanRT_baseline: the baseline mean reaction time in ms SD_baseline: the standard deviation of the baseline reaction times in ms baselineRT60: the 60th percentile reaction time (in ms) based on mean and standard deviation: X = z-score(60th percentile)*SD + mean total_control: the total earned in control condition total_reward: the total earned in reward condition total_punishment: the total earned in punishment condition propCorrect_IncentiveReward: proportion correct for incentive trials in the reward condition propCorrect_NonIncentiveReward: proportion correct for nonincentive trials in the reward condition propCorrect_IncentivePunishment: proportion correct for incentive trials in the punishment condition propCorrect_NonIncentivePunishment: proportion correct for nonincentive trials in the punishment condition propCorrect_IncentiveControl: proportion correct for incentive trials in the control condition propCorrect_NonIncentiveControl: proportion correct for nonincentive trials in the control condition ___________________________________________________________________________________________________________________ EXPERIMENTAL SET-UP ___________________________________________________________________________________________________________________ 3 conditions: Control vs. Reward vs. Punishment, tested within in a blocked design. All participants start with the Control condition. The assignment to Reward -> Punishment vs. Punishment -> Reward is counterbalanced by groupnumber (odd groupnumbers start with Reward; even groupnumbers start with Punishment) In each condition: - 100 trials - 20 incentive trials - 80 nonincentive trials => The order is randomized with the constraint that incentive trials cannot be presented consecutively - the color for incentive/nonincentive trials is different for each condition Trial Sequence (6000ms): cue (500ms) -> random delay* (4000-4500ms)-> target (variable, duration = 60th percentile RT)** -> Feedback (500ms) -> ITI (variable to round trial sequence duration to ~6s) *Random Delay: is controlled by list.delay under section Editable Lists **Target Durations: in this script, the targetduration is set to the 60th percentile RT as assessed during baseline ~ 60% correct performance Knutson et al (2000) report to have used targetdurations beween 160ms and 260ms (p.21) Note: if the 60th percentile > 500ms the script aborts automatically (500ms is the max. possible target duration given all other default trial durations) ___________________________________________________________________________________________________________________ STIMULI ___________________________________________________________________________________________________________________ cues/targets: squares (size can be controlled via parameters.stimsize under section Editable Values) targets: white in all conditions Control: incentive cue: red; nonincentive cue: green Reward: incentive cue: orange; nonincentive cue: blue Punishment: incentive cue: yellow; nonincentive cue: pink ___________________________________________________________________________________________________________________ INSTRUCTIONS ___________________________________________________________________________________________________________________ are not original to Knutson et al (2000) - they can be edited under section Editable Instructions ___________________________________________________________________________________________________________________ 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: /responsekey: the response key (default: " " = Spacebar) /cueduration: the duration of the cue in ms (default: 500) /feedbackduration: the duration of the feedback in ms (default: 500) /trialduration: the duration of a complete trial sequence in ms (default: 6000) /Reward_win: the number of points ($) won in the Reward condition (default: 1) /Punishment_loss: the number of points ($) lost in the Punishment condition (default: 1) /punishment_startamount: the amount of money provided at the beginning of the punishment condition (default: 20) /reward_startamount: the amount of money provided at the beginning of the reward condition (default: 0) /control_startamount: the amount of money provided at the beginning of the control condition (default: 0) /stimsize: the size of the cues/targets as percentages of canvas height (default: 10%) /presenttotal: true = present the "Total earned" throughout Reward and Punishment Blocks. false = does not present the "Total earned" throughout Reward and Punishment Blocks. Note: the expressions under Editable values can be changed to change the 10 targetdurations.