Understanding Effort and Fatigue

This study is looking for healthy right-handed adults aged 18 to 35 to understand how people experience and value effort, especially when they are feeling tired. You would participate in tasks designed to create cognitive (mental) fatigue and physical fatigue, such as repeatedly performing a spatial attention task or a grip force task. Researchers will also use rewarding stimuli to see how motivation affects your effort choices. The main goal is to measure how much effort you feel these tasks require, both before and after becoming fatigued. This study aims to enroll 185 participants and is not currently recruiting.

Study design
This is an interventional study with a planned enrollment of 185 participants. The study aims to understand how people value effort and how fatigue and motivation influence this.
What's involved
Not specified in the trial record.
Compensation
Not stated in the trial record.
Follow-up
Your subjective effort parameters will be measured on day 1.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT04041154

Behavioral and Neural Representations of Subjective Effort Cost

Recruiting
NAAges 18–35InterventionalBasic science
Hugo W. Moser Research Institute at Kennedy Krieger, Inc.
~185 participants
Updated 2026-01-26 on ClinicalTrials.gov
What's tested:Cognitive FatiguePhysical FatigueRewarding Stimuli

At a glance

Recruiting sites
1 of 1 listed site is recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Mean of cognitive subjective effort parameters (from behavioral choice data)
Measured over 1 day
+11 more outcomes measured
Fatigue
1 sites across 1 states
Maryland1
  • Vikram S. Chib, PhD · PRINCIPAL_INVESTIGATOR · Kennedy Krieger Institute and Johns Hopkins School of Medicine

Opens a ready-to-send draft in your own email app — review before sending.

Do you actually qualify for this trial?

Add a private profile and we'll compare every criterion below against your situation — and tell you which ones are met, uncertain, or excluding.

Check eligibility for this trial ~2 min · HIPAA-protected · delete anytime
Eligibility criteria

Inclusion

Right-handed
Age between 18 and 35 years old - Male or female
Any ethnicity

Exclusion

Neurological problems such as stroke, head injury, epilepsy, seizures, brain tumors, brain surgery, Parkinson's Disease (self- report)
Diagnosed history of severe psychiatric disease such as depression, schizophrenia (self-report)
Metal in the head or eyes
If they are pregnant or suspect that you may be pregnant
If they experience discomfort from the MRI scan, such as severe claustrophobia or excessive heating of tattoos
  • Mean of cognitive subjective effort parameters (from behavioral choice data)1 day

    Choice data will be fit to a model of the form u(x) = x\^rho. The parameter rho is indicative of individuals' subjective preferences for effort. We will test if participants cognitive subjective effort parameters will be significantly different than zero. Effort levels will be expressed as a percentage of each individual's maximum exertion capacity. This will ensure that comparisons can be made between participants.

  • Differences between cognitive subjective effort parameters before and after fatigue (from behavioral choice data)1 day

    Choice data will be fit to a model of the form u(x) = x\^rho. The parameter rho is indicative of individuals' subjective preferences for effort. We will test if participants cognitive subjective effort parameters will be significantly different when comparing parameters extracted from pre-fatigue and post-fatigue choices. Effort levels will be expressed as a percentage of each individual's maximum exertion capacity. This will ensure that comparisons can be made between participants.

  • Mean of physical subjective effort parameters (from behavioral choice data)1 days

    Choice data will be fit to a model of the form u(x) = x\^rho. The parameter rho is indicative of individuals' subjective preferences for effort. We will test if participants physical subjective effort parameters will be significantly different than zero. Effort levels will be expressed as a percentage of each individual's maximum exertion capacity. This will ensure that comparisons can be made between participants.

  • Differences between physical subjective effort parameters before and after fatigue (from behavioral choice data)1 day

    Choice data will be fit to a model of the form u(x) = x\^rho. The parameter rho is indicative of individuals' subjective preferences for effort. We will test if participants physical subjective effort parameters will be significantly different when comparing parameters extracted from pre-fatigue and post-fatigue choices. Effort levels will be expressed as a percentage of each individual's maximum exertion capacity. This will ensure that comparisons can be made between participants.

  • Difference between cognitive effort cost parameters between the low and high reward stimuli1 day

    Choice data will be fit to a model of the form u(x) = x\^rho. The parameter rho is indicative of individuals' subjective preferences for effort. We will test if participants subjective effort parameters will be significantly different when comparing parameters extracted from low and high reward stimuli trials. Effort levels will be expressed as a percentage of each individual's maximum exertion capacity. This will ensure that comparisons can be made between participants.

  • Difference between physical effort cost parameters between the low and high reward stimuli1 day

    Choice data will be fit to a model of the form u(x) = x\^rho. The parameter rho is indicative of individuals' subjective preferences for effort. We will test if participants subjective effort parameters will be significantly different when comparing parameters extracted from low and high reward stimuli trials. Effort levels will be expressed as a percentage of each individual's maximum exertion capacity. This will ensure that comparisons can be made between participants.

  • Regions of the brain encoding cognitive effort1 day

    We will use a general linear model to examine brain activity that is positively and negatively correlated with chosen cognitive effort value.

  • Regions of the brain encoding physical effort1 day

    We will use a general linear model to examine brain activity that is positively and negatively correlated with chosen physical effort value.

  • Regions of the brain encoding changes cognitive effort value following cognitive fatigue1 day

    We will use a general linear model to examine brain activity that is positively and negatively correlated with fatigue-induced changes in cognitive effort value.

  • Regions of the brain encoding changes physical effort value following physical fatigue1 day

    We will use a general linear model to examine brain activity that is positively and negatively correlated with fatigue-induced changes in physical effort value.

  • Regions of the brain encoding differences in cognitive effort value resulting from reward-induced changes in motivation1 day

    We will use a general linear model to examine brain activity that is positively and negatively correlated with motivation-induced changes in cognitive effort value.

  • Regions of the brain encoding differences in physical effort value resulting from reward-induced changes in motivation1 day

    We will use a general linear model to examine brain activity that is positively and negatively correlated with motivation-induced changes in physical effort value.