Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond
Created: September 28, 2015
Last Modified: July 16, 2026 by K. Borchert (katjab@millisecond.com), Millisecond
Script Copyright © Millisecond Software, LLC
This script implements the Effort Expenditure for Rewards Task (EEfRT); a measure of reward motivation for physical work. The implemented procedure is based on Treadway et al (2009).
Treadway MT, Buckholtz JW, Schwartzman AN, Lambert WE, Zald DH (2009) Worth the ‘EEfRT’? The Effort Expenditure for Rewards Task as an Objective Measure of Motivation and Anhedonia. PLoS ONE 4(8): e6598. doi:10.1371/journal.pone.0006598
23 minutes
Participants have to select between an Easy and a Hard task. Both tasks involve pressing the Spacebar for a predetermined amount of time. The Hard task offers more money (in this script: 8 variable amounts) but is harder and takes twice as long. Participants make their selection knowingly under 3 different win probabilities (aka they might not win money even if they are successful; particularly not if the win probabilities are low). By default, E selects the Easy task and I selects the Hard task (can be edited under section Editable Parameters).
The instructions are not original to Treadway et al (2009). They are provided by Millisecond.
They can be edited under section Editable Instructions.
File Name: effortexpenditureforrewardtask_summary*.iqdat
| Name | Description |
|---|---|
| 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 |
| inquisit.version | Inquisit version number |
| computer.platform | Device platform: win | mac |ios | android |
| computer.touch | 0 = device has no touchscreen capabilities; 1 = device has touchscreen capabilities |
| computer.hasKeyboard | 0 = no external keyboard detected; 1 = external keyboard detected |
| completed | 0 = Test was not completed 1 = Test was completed |
Summary Data: Based On Full Cycles Only (Trial Sequences That Were Cut Short Due To Time Constraints Do Not Count Towards Summary Variables) |
|
| randomwin1 | Stores the first randomly selected win amount (in case this is used for an extra incentive) |
| randomwin2 | Stores the second randomly selected win amount (in case this is used for an extra incentive) |
| total | Stores the total of all rewards earned |
| countTestTrials | Counts the number of testtrials (forced + unforced) |
| countForced | Counts the number of times computer had to randomly select a level of difficulty for participant |
The Following Variables Only Use Performance Metrics From Trials That Were Not Forced (Aka Not Randomly Assigned By Computer After 5S) |
|
| countValidTestTrials | Counts the number of unforced selections during the test |
| countEasy | Counts the number of easy trials |
| countHard | Counts the number of hard trials |
| countSuccessEasy | Counts the number of successful easy trials |
| countSuccessHard | Counts the number of successful hard trials |
| meanTaskDurationE | Mean successful taskduration (pressing button; in ms) of the easy task |
| meanTaskDurationH | Mean successful taskduration (pressing button; in ms) of the hard task |
| meanRTSelection | Mean latency (in ms) of selection |
| meanRTH | Mean latency (in ms) of hard selections |
| meanRTE | Mean latency (in ms) of easys selections |
| propH | Overall proportion of non-forced choices of the difficult task relative to the number of all non-forced selections => Overall preference metric |
| propHP1 | Proportion of non-forced choices of the difficult task relative to the number of all non-forced selections for win probability level1 |
| propHP2 | Proportion of non-forced choices of the difficult task relative to the number of all non-forced selections for win probability level2 |
| propHP3 | Proportion of non-forced choices of the difficult task relative to the number of all non-forced selections for win probability level3 |
All Interaction Cells (For Proportion Hard Choices And Selection Time) |
|
| propHP1R1 | Proportion Hard Choices for Level1 probability (low win probability: 12%) and Level1 reward (lowest reward level) .. |
| propHP2R8 | Example of a conflict trial proportion Hard Choices for Level2 probability (mid win probability: 50%) and Level8 reward (highest reward level) => 'Does the possible high reward offset the uncertain chance of winning it?' ... |
| propHP3R8 | Proportion Hard Choices for Level3 probability (high win probability: 88%) and Level8 reward (highest reward level) |
| meanRTHP1R1 | Mean selection time (in ms) for choosing the Hard task for Level1 probability (low win probability: 12%) and Level1 reward (lowest reward level) ... |
| meanRTHP2R8 | Example of a conflict trial mean selection time (in ms) for choosing the Hard task for Level2 probability (mid win probability: 50%) and Level8 reward (highest reward level) . |
| meanRTHP3R8 | Mean selection time (in ms) for choosing the Hard task for Level3 probability (high win probability: 88%) and Level1 reward (highest reward level) |
File Name: effortexpenditureforrewardtask_raw*.iqdat
| Name | Description |
|---|---|
| date | Date the session was run |
| time | Time the session was run |
| subject | Participant ID |
| group | Group number |
| session | Session number |
| build | Inquisit version number |
| computer.platform | Device platform: win | mac |ios | android |
| computer.touch | 0 = device has no touchscreen capabilities; 1 = device has touchscreen capabilities |
| computer.hasKeyboard | 0 = no external keyboard detected; 1 = external keyboard detected |
| blockcode | The name the current block (built-in Inquisit variable) |
| blocknum | The number of the current block (built-in Inquisit variable) |
| trialcode | The name of the currently recorded trial (built-in Inquisit variable) |
| trialnum | The number of the currently recorded trial (built-in Inquisit variable) trialnum is a built-in Inquisit variable; it counts all trials run even those that do not store data to the data file. |
| practice | 0 = test; 1 = practice |
| countTestTrials | Counts the number of COMPLETED testtrials |
| rewardEasy | The potential reward assigned to the Easy task (default: "1.00") |
| rewardHard | The currently assigned reward amount for the hard task |
| rewardHardLevel | The level of the assigned hard reward amount (1-8) |
| winProbability | The currently assigned win probability |
| winProbabilityLevel | The level of the assigned win probability (1-3) |
| selectionResponse | The key scancode of the selection response |
| forced | 1 = the task difficulty was randomly assigned to participant (did not choose themselves) 0 = participant selected difficulty |
| selectedDifficulty | The task difficulty chosen/assigned: 0 = easy task; 1 = hard task |
| selectedTask | "easy" vs. "hard" |
| selectionrt | The latency of the selection in ms (excludes forced choices) |
| countPresses | Counts the button presses of the current trial |
| finalTaskDuration | The duration (in ms) spent on the task (pressing buttons) |
| success | 1 = task was successfully completed; 0 = task was not completed |
| win | 1 = the successful completion is rewarded; 0 = the successful completion is not rewarded |
| currentReward | The currently assigned (potential) reward amount for the task chosen |
| total | Stores the total of all rewards earned |
The procedure can be adjusted by setting the following parameters.
| Name | Description | Default |
|---|---|---|
Colors |
||
| screenColor | The color of the 'inactive' screen | white |
| canvasColor | The color of the 'active' screen if changed, you may need to change the taskselection images | white |
| defaultTextColor | The default text color | black |
Design |
||
| rewardEasy | The potential reward assigned to the Easy task | "1.00" |
| easyPresses | Number of button presses for the Easy task | 30 |
| hardPresses | Number of button presses for the Hard task | 100 |
| maxPayOff | Default: ""; no maximum payoff is set If set to a number, then the script terminates when that number is reached | "" |
| showTimer | Show a timer while performing the task | false |
Timing Parameters |
||
| completeTaskDuration | The duration of the completed task in ms -> 20min | 1200000 |
| selectionWindow | The max. response window to make the task selection in ms | 5000 |
| readyDuration | The duration of the Ready screen in ms | 1000 |
| easyDuration | The max. duration of the Easy task in ms | 7000 |
| hardDuration | The max. duration of the Hard task in ms | 21000 |
| successFeedbackDuration | The duration of the feedback screen regarding success/failure in ms | 2000 |
| winFeedbackDuration | The duration of the feedback screen regarding the reward money won in ms | 2000 |
Response Keys |
||
| responseKeyEasy | The response key for the Easy selection | "E" |
| responseKeyHard | The response key for the Hard selection | "I" |