Mental Resources: Pricing Mental Effort

Last registered on April 28, 2022


Trial Information

General Information

Mental Resources: Pricing Mental Effort
Initial registration date
April 21, 2022

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
April 28, 2022, 5:49 PM EDT

First published corresponds to when the trial was first made public on the Registry after being reviewed.



Primary Investigator

Harvard University

Other Primary Investigator(s)

PI Affiliation
Carnegie Mellon University

Additional Trial Information

Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
The purpose of this study is to measure the disutility of mental effort. We do this by experimentally varying the amount of mental effort that a computerized task requires across subjects. We then elicit each subject's reservation wage for repeating the task.
External Link(s)

Registration Citation

Loewenstein, George and Zachary Wojtowicz. 2022. "Mental Resources: Pricing Mental Effort." AEA RCT Registry. April 28.
Experimental Details


Participants will be randomized into three variants of a computerized real effort task. The variants are designed to induce low, medium, and high levels of effort.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Our key measures will be: subjective (Likert scale) ratings of mental effort, boredom, interest, and frustration after completing the task; willingness to accept (reservation wage) for repeating the main task; working memory, elicited using a digit span task; and outside offer/opportunity cost, measured as self-reported average MTurk wage.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Participants will complete the following experimental blocks: (1) digit span, (2) n-back, (3) state measures, (4) wage BDM, and, potentially (5) a second n-back.
Experimental Design Details
First, we elicit a proxy for participant working memory capacity by measuring the number of digits they can recall in order (a classic digit span test). Participants will then be randomized into three variants of a sequential letter-based n-back task (0, 1, and 2-back). We subsequently measure subjective evaluations of mental effort, boredom, interest, and frustration by asking subjects to rate the task using a slider that ranges from, e.g. "not at all mentally effortful" to "extremely mentally effortful". The main dependent measure is a participant's reservation wage (WTA) for doing an additional 3 minutes of the main task. This variable is elicited using a Becker-Degroot-Marschak multiple price list that ranges from $0.00 to $1.00 in increments of $0.05. The implied hourly wage is also displayed next to each of these fixed amounts in a separate column. Subjects indicate "yes" or "no" for each amount.
Randomization Method
Randomization is implemented electronically though Qualtrics.
Randomization Unit
Individual participants will be randomized into the three experimental conditions.
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
Our design does not feature clustering.
Sample size: planned number of observations
We will collect data from 900 participants in total.
Sample size (or number of clusters) by treatment arms
We will collect data for 300 participants per condition, for a total of 900 participants.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
The Carnegie Mellon University Institutional Review Board
IRB Approval Date
IRB Approval Number
Analysis Plan

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Post Trial Information

Study Withdrawal

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Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials