Cognitive Effort Expenditure for Rewards Task - CEEfRT

Technical Manual

Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond

Created: December 22, 2025

Last Modified: February 04, 2026 by K. Borchert (katjab@millisecond.com), Millisecond

Background

This script implements the Cognitive Effort Expenditure for Rewards Task (cEEfRT); a measure of reward motivation for cognitive work (Gamundi & Wardle, 2018). The implemented procedure is based on Treadway's et al (2009) EEfRT task and Botvinich's et al (2009) Cognitive Effort Discounting Task.

References

Lopez-Gamundi, P & Wardle, MC (2018). The cognitive effort expenditure for rewards task (C-EEfRT): A novel measure of willingness to expend cognitive effort. Psychol Assess, Sep;30(9):1237-1248. doi: 10.1037/pas0000563. Epub 2018 Apr 5. PMID: 29620381.

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

Botvinick MM, Huffstetler S, McGuire JT (2009) Effort discounting in human nucleus accumbens. Cogn Affect Behav Neurosci 9:16–27.

Duration

23 minutes

Description

Participants have to select between an Easy and a Difficult categorization task. Both tasks involved magnitude and/or parity tasks.

Numbers ranging from one to nine (excluding five) are presented on screen in either blue or a yellow font. If the number is blue, participants need to indicate as quickly as possible whether the number was even or odd (parity task). If the number is yellow, participants need to indicate as quickly as possible whether the number was <5 or >5 (magnitude task).

EASY task: - same task throughout (no switch task) - max. 4 judgments required for completion - response reminders

DIFFICULT task: - alternating tasks (switch task) - max. 19 judgments required for completion - no response reminders

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 Difficult task (can be edited under section Editable Parameters).

Procedure

Practice:

- 4 trials: The first 2 trials provide the choices (Easy->Difficult; if something else is chosen, the choice is "corrected");
for the last 2 trials participants are free to choose either task.
Reward Amounts for the difficult task (same as for test) are selected randomly from 4 options (without replacement);
Win probabilities (same as for test) are randomly selected (with replacement).
In this script, practice trial provide a reminder description of the tasks for the "Ready" screen (Ready screen is presented for 2000ms)

practice performance is required to be 100% correct to move on to the test session.
If performance is below 100%, the practice session gets repeated. The maximum number of practice rounds is set to 10 (editable parameter).
After 10 practice rounds, all participants move on to the test session. Variable 'practiceSuccess' can be used as a filter to filter
out those participants who have never mastered the practice session.

Test:

- 20 minutes total: the number of trials run per participant during that timeframe depends on
- how fast they make their selection
- the type of task they select
- how fast they complete the task

- 3 win probabilities: 88%, 50%, 12% (can be edited under section Editable List; the probabilities are 'true' probabilities and not frequencies)
- difficult task reward amounts: $1.24-$4.30 (in this script: in steps of $0.43)
=> 8 levels (1.24,1.68,2.11,2.55,2.99,3.43,3.86,4.3; mean = 2.77)
- each level of probability (3) is paired with each level of difficult task reward (8) twice within every 48 trials in this script
=> expected money for successfully completing difficult task for (every) 48 trials: $2.77 * 48 * average(0.12, 0.5, 0.88) = $66.48
=> IF twice as many (successful) easy trials are run in the same time frame: = $1 * (2 * 48) * average(0.12, 0.5, 0.88) = $48
=> a maximum payoff can be set in this script (if it's reached, the task is terminated)
- the presentation of the different combinations of difficult reward tasks x probabilities was randomized for 2 lists of 48 trials and is presented
in fixed order to each participant (see list.rewardsDifficult).

Trial Sequence:

Selection Screen (max. 5000ms)*->Ready Screen (1000ms)->Task Screen (max.7s or max.21s)->success/failure feedback screen (2000ms)->potentially win screen (2000ms)

•If no selection is made within 5000ms, the computer randomly selects a task for the participant

Stimuli

digits: 1-9 (except 5) in blue and yellow

Instructions

The instructions are not original to Lopez-Gamundi & Wardle (2018). They are provided by Millisecond.
They can be edited in script c_eefrt_instructions_inc.iqjs

Scoring

Success

In this script success is defined as 'the minimum number of required correct responses completed in time'.
The minimum required correct responses is thus calculated as = the max number of judgments required x the minimum proportion correct judgments required
This definition was implemented to allow for the possibility of occasional errors.

Example with with 80% correct performance:
Easy: max 4 judgments X 0.8 = 3.2 correct responses => need all 4 responses to be correct to reach success
Difficult: max. 19 judgements X 0.8 = 15.2 => need 16 responses to be correct to reach success

The success meter is adjusted by the number of minimum correct responses required. Thus, if participant
in the difficult condition responded correct to the first 16 judgments in time, the meter already reaches the top and
the participant has fullfilled the success criteria.

The max number of judgements as well as the minimum proportion correct judgments that are required
can be fine tuned under section Editable Parameters.
The default setting of the script requires 100% correct performance.

Summary Data

File Name: c_eefrt_summary*.iqdat

Data Fields

Name	Description
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
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
practiceCounter	Tracks the number of practice session run
practiceSuccess	1 = 100% practice performance achieved, 0 = otherwise
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
countEasy	Counts the number of easy trials (includes forced easy trials)
countDifficult	Counts the number of difficult trials (includes forced difficult trials)
countSuccessEasy	Counts the number of successful easy trials
countSuccessDifficult	Counts the number of successful difficult trials
countForced	Counts the number of times computer had to randomly select a level of difficulty for participant
meanRTSelection	Mean latency (in ms) of selection (excludes forced selections)
meanTaskDurationE	Mean successful taskduration (pressing button; in ms) of the easy task
meanTaskDurationD	Mean successful taskduration (pressing button; in ms) of the difficult task
proportionNonforcedDifficultChoices	Overall proportion of non-forced choices of the difficult task relative to all trials
meanRTNonforcedDifficultChoices	Overall mean choice response time (in ms) for selecting difficult task (non-forced)
proportionNonforcedDifficultChoicesP1	Proportion of non-forced choices of the difficult task for win probability p1 (12% chance)
meanRTNonforcedDifficultChoicesP1	Overall mean choice response time (in ms) for selecting difficult task (non-forced) for win probability p1 (12% chance)
proportionNonforcedDifficultChoicesP2	Proportion of non-forced choices of the difficult task for win probability p2 (50% chance)
meanRTNonforcedDifficultChoicesP2	Overall mean choice response time (in ms) for selecting difficult task (non-forced) for win probability p2 (50% chance)
proportionNonforcedDifficultChoicesP3	Proportion of non-forced choices of the difficult task for win probability p3 (88% chance)
meanRTNonforcedDifficultChoicesP3	Overall mean choice response time (in ms) for selecting difficult task (non-forced) for win probability p3 (88% chance)
Task Performance: Acc
propCorrectOverall	Mean proportion correct across all performed parity/magnitude tasks
propCorrectP	Mean proportion correct across all performed PARITY tasks
propCorrectM	Mean proportion correct across all performed MAGNITUDE tasks
propCorrectEasy	Mean proportion correct across all performed EASY parity/magnitude tasks
propCorrectDifficult	Mean proportion correct across all performed DIFFICULT parity/magnitude tasks
propCorrectPEasy	Mean proportion correct across all performed EASY PARITY tasks
propCorrectPDifficult	Mean proportion correct across all performed DIFFICULT PARITY tasks
propCorrectMEasy	Mean proportion correct across all performed EASY MAGNITUDE tasks
propCorrectMDifficult	Mean proportion correct across all performed DIFFICULT MAGNITUDE tasks
Task Performance: Rt
meanCorrRTOverall	Mean correct RT (in ms) across all performed parity/magnitude tasks
meanCorrRTP	Mean correct RT (in ms) across all performed PARITY tasks
meanCorrRTM	Mean correct RT (in ms) across all performed MAGNITUDE tasks
meanCorrRTEasy	Mean correct RT (in ms) across all performed EASY parity/magnitude tasks
meanCorrRTDifficult	Mean correct RT (in ms) across all performed DIFFICULT parity/magnitude tasks
meanCorrRTPEasy	Mean correct RT (in ms) across all performed EASY PARITY tasks
meanCorrRTPDifficult	Mean correct RT (in ms) across all performed DIFFICULT PARITY tasks
meanCorrRTMEasy	Mean correct RT (in ms) across all performed EASY MAGNITUDE tasks
meanCorrRTMDifficult	Mean correct RT (in ms) across all performed DIFFICULT MAGNITUDE tasks

Raw Data

File Name: c_eefrt_raw*.iqdat

Data Fields

Name	Description
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
date	Date the session was run
time	Time the session was run
subject	Participant ID
group	Group number
session	Session number
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
practiceCounter	Tracks the number of practice session run
practiceSuccess	1 = 100% practice performance achieved, 0 = otherwise
countTestTrials	Counts the number of COMPLETED testtrials
rewardEasy	The potential reward assigned to the Easy task (default: "1.00")
rewardDifficult	The currently assigned reward amount for the difficult task
winProbability	The currently assigned win probability
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 = difficult task
selectedTask	"easy" vs. "difficult"
currentCategorizationTask	1 = parity (blue); 2= magnitude (yellow)
digit	Stores the currently presented digit for the parity/magnitude task
corrResp	Stores the current correct response key for the parity/magnitude task
correct	1 = the response is correct; 0 = error response
latency	The response latency (in ms); measured from start of trial
selectionRT	The latency of the selection in ms (excludes forced choices)
countAttempts	Attempted judgments
minCorrect	Minimum number of judgments that need to be correct in order to reach success
countCorrect	Counts the number of correct responses for the current game
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
finalTaskDuration	The duration (in ms) spent on the task (pressing buttons)

Parameters

The procedure can be adjusted by setting the following parameters.

Name	Description	Default
Colors
screenColor	The color of the 'inactive' screen	black
canvasColor	The color of the 'active' screen if changed, you may need to change the taskselection images	black
defaultTextColor	The default text color	white
meterColor	The default meter color	red
Design
maxPracticeRuns	Number of times practice session is run if performance is below 100%	10
rewardEasy	The potential reward assigned to the Easy task	"1.00"
easyTrials	Maximum number of trials to perform for the easy task	4
difficultTrials	Maximum number of trials to perform for the difficult task	19
minAcc	Minimum proportion correct of the maximum trials that is needed for successful completion changes to this setting would allow occasional errors	1.00
showTimer	Show a timer while performing the task	true
maxPayOff	Default: ""; no maximum payoff is set If set to a number, then the script terminates when that number is reached	""
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
difficultDuration	The max. duration of the difficult 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: If Changed, Images May Have To Be Updated Manually (The Task Itself Adjusts Automatically)
responseKeyEasy	The response key for the Easy selection ; needs to stay the LEFT key	"E"
responseKeyDifficult	The response key for the Difficult selection ; needs to stay the RIGHT key	"I"
responseKeyLeft	The designated left response key (QWERTY keyboard) for the parity/magnitude tasks	"E"
responseKeyRight	The designated right response key (QWERTY keyboard) for the parity/magnitude tasks	"I"
responseKeyEven	The designated response key for EVEN parity task responses	parameters.responseKeyRight
responseKeyOdd	The designated response key for ODD parity task responses	parameters.responseKeyLeft
responseKeySmaller	The designated response key for <5 magnitude task responses	parameters.responseKeyLeft
responseKeyLarger	The designated response key for >5 magnitude task responses	parameters.responseKeyRight

Cognitive Effort Expenditure for Rewards Task - CEEfRT

Technical Manual

Background

References

Duration

Description

Procedure

Practice:

Test:

Trial Sequence:

Stimuli

Instructions

Scoring

Success

Summary Data

Data Fields

Summary Data: Based On Full Cycles Only (Trial Sequences That Were Cut Short Due To Time Constraints Do Not Count Towards Summary Variables)

Task Performance: Acc

Task Performance: Rt

Raw Data

Data Fields

Parameters

Colors

Design

Timing Parameters

Response Keys: If Changed, Images May Have To Be Updated Manually (The Task Itself Adjusts Automatically)