Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond
Created: August 28, 2015
Last Modified: August 14, 2023 by K. Borchert (katjab@millisecond.com), Millisecond
Script Copyright © Millisecond Software, LLC
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
30 minutes
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.
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
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
are not original to Knutson et al (2000) - they can be edited under section Editable Instructions
File Name: monetaryincentivedelaytask_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 |
| order | 'reward->punish' vs. 'punish->reward' |
| meanRTBaseline | The baseline mean reaction time in ms |
| sdBaseline | 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 |
| totalControl | The total earned in control condition |
| totalReward | The total earned in reward condition |
| totalPunishment | The total earned in punishment condition |
| propCorrectIncentiveReward | Proportion correct for incentive trials in the reward condition |
| propCorrectNonIncentiveReward | Proportion correct for nonincentive trials in the reward condition |
| propCorrectIncentivePunishment | Proportion correct for incentive trials in the punishment condition |
| propCorrectNonIncentivePunishment | Proportion correct for nonincentive trials in the punishment condition |
| propCorrectIncentiveControl | Proportion correct for incentive trials in the control condition |
| propCorrectNonIncentiveControl | Proportion correct for nonincentive trials in the control condition |
File Name: monetaryincentivedelaytask_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, group, | With the current subject/groupnumber |
| 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 |
| expCondition | 0 = control condition; 1 = Reward condition; 2 = Punishment Condition |
| order | 'reward->punish' vs. 'punish->reward' |
| incentiveCondition | 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) |
| totalControl | The total earned in control condition |
| totalReward | The total earned in reward condition |
| totalPunishment | The total earned in punishment condition |
The procedure can be adjusted by setting the following parameters.
| Name | Description | Default |
|---|---|---|
Design Parameters |
||
| rewardWin: | The number of points ($) won in the Reward condition | 1 |
| punishmentLoss: | The number of points ($) lost in the Punishment condition | 1 |
| punishmentStartAmount: | The amount of money provided at the beginning of the punishment condition | 20 |
| rewardStartAmount: | The amount of money provided at the beginning of the reward condition | 0 |
| controlStartAmount: | The amount of money provided at the beginning of the control condition | 0 |
| presentTotal: | True = present the "Total earned" throughout Reward and Punishment Blocks. false = does not present the "Total earned" throughout Reward and Punishment Blocks. | true |
Timing Parameters |
||
| cueDuration: | The duration of the cue in ms | 500 |
| feedbackDuration: | The duration of the feedback in ms | 500 |
| trialDuration: | The duration of a complete trial sequence in ms | 6000 |
Sizing Parameters |
||
| stimSize: | The size of the cues/targets as percentages of canvas height | 10% |
Response Key |
||
| responseKey: | The response key the expressions under Editable values can be changed to change the 10 targetdurations. | " " |