Physical Activity Incentives

In this study, the investigators will test responsiveness of young, middle-aged, and older adults to a range of incentives, some of which provide rewards for the individual participants and others that offer rewards to other people or groups. The investigators hypothesize that incentives are differentially effective for different age groups.

Study Overview

• Status: Completed
• Conditions: Physical Activity
• Intervention / Treatment: Other: Offering a financial incentive to increase walking

Detailed Description

This study grounds a financial incentives intervention in well-documented age-related changes in motivation. The investigators consider these motivational shifts through the lens of socioemotional selectivity theory (SST, Carstensen, 2006). According to SST, perceived time horizons influence motivation across the life span. When time is perceived as expansive (typical of younger adults), exploration and achievement are prioritized, but when time horizons narrow (typical of older adults), emotional meaning and satisfaction are prioritized. Previous research has shown that socioemotional goals may influence decisions about healthcare plans and the effectiveness of motivational messages to increase physical activity (Löckenhoff & Carstensen, 2007; Mikels et al., 2010; Notthoff & Carstensen, 2013). Drawing on the tenets of SST, individuals may be more motivated to engage in physical activity when doing so aligns with socioemotional goals. For example, older adults may find physical activity most appealing when it promotes emotional meaning and satisfaction; in contrast, younger adults may find physical activity most appealing when it promotes exploration and achievement.

Recent work has shown that spending on others (termed "prosocial spending") can have greater emotional benefits than spending on oneself (Anik, Aknin, Norton, Dunn, & Quoidbach, 2013; Dunn, Aknin, & Norton, 2008). Extending this concept, the researchers posit that, in the context of financial incentives, earning for others may offer older adults a more emotionally meaningful alternative to individual financial incentives, which may, in turn, better support health behavior change for older adults. Because of the profound link between physical activity and risk for cardiovascular disease and stroke, and because previous research suggests that financial incentives are most effective for simple, well-defined, objectively measurable activities, the behavioral outcome of interest in this study focuses on walking measured by pedometer step counts (Scott & Schurer, 2008). In addition, because SST postulates specifically about motivational priorities in younger relative to older adults, the investigators recruited adult participants of all ages. The researchers designed this study to test the effectiveness of prosocial relative to individual financial incentives for increasing walking in older and younger adults. Reasoning from SST, the investigators hypothesize that younger adults will be relatively more motivated by incentives that produce personal benefits (i.e. individual financial incentives), but older adults will be relatively more affected when incentives were more emotionally meaningful (i.e. benefit another person or social cause). The investigators also predict that, when given the choice of incentive, older adults will be more likely to choose to earn for others rather than to earn for themselves, relative to younger adults. In addition, the investigators will also test the effects of prosocial relative to individual financial incentives on intrinsic motivation for physical activity and behavioral maintenance (maintaining increased steps) once incentives are removed.

Community-residing adults aged 18 and older are recruited via advertisements on Internet bulletin boards and local newspapers to participate in a study that requires four visits to our laboratory and three weeks of pedometer wear in exchange for $50. Importantly, participants are unaware of the incentive component of this study. Once participants contact research staff to indicate their interest, they are phone screened for eligibility (see the eligibility criteria section of this entry).

During the first in-lab session, after providing informed consent, participants respond to a series of questionnaires using Qualtrics survey software. Participants are provided with a pedometer, instructed on its use, and asked to wear it each day. One week later, participants return to complete the second study session. Participants complete questionnaires while pedometer steps are downloaded. Participants are randomly assigned within age group and gender to one of five possible incentive conditions (which can be found in the arms and interventions section of this entry). One week later, participants return to the lab for the third study session where they complete questionnaires while pedometer steps are downloaded. All participants are told their average daily steps from the previous week and how this average relates to the first week's average. Participants in incentivized conditions who increase steps are told how much they earned. Participants in the personal condition and choice participants who elect to keep the earnings receive a check for the amount of their earnings. Participants in the loved one and charity conditions and choice participants who elect to give their earnings to a loved one or charity witness the research staff write a check for the amount of their earnings to their selected loved one or charity and enclose the check along with a cover letter into an envelope to be mailed. Participants in the incentivized conditions who do not increase steps were told that they did not earn any money. All participants in incentivized conditions are reminded that the incentive portion of the study is complete and that they will not earn money by changing steps the final week of the study. One week later, participants complete the final study session. Participants complete questionnaires while pedometer steps are downloaded. All participants are told their average daily steps from the previous week and how this average relates to the second week's average. At the end of the session, participants are debriefed, paid, and thanked for their participation.

• Study Type: Interventional
• Enrollment (Actual): 450
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • California
    • Stanford, California, United States, 94305
      • Life-span Development Lab

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Adults aged 18 and older are being targeted. We aim to recruit equal numbers of men and women, but this is not a specific target. There are no racial or ethnic targets.
• Individuals who pass a phone screening that includes physical (PAR-Q) and cognitive (MMSE) measures are eligible for this study. These individuals must either answer "no" to all the questions on the Physical Activity Readiness Questionnaire (PAR-Q) or receive verbal permission from their doctor. Additionally, they must also show no signs of cognitive impairment as indicated by scores greater than or equal to 23 points on the 26-point Mini-Mental State Examination (MMSE).

Exclusion Criteria:

• We will not recruit minors (17 or younger) because this is a study of adult development.
• Individuals who answered "yes" on any questions of the PAR-Q and/or received a score less than or equal to 22 on the MMSE.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: BASIC_SCIENCE
• Allocation: RANDOMIZED
• Interventional Model: FACTORIAL
• Masking: SINGLE

Number of Arms

5

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: Personal - self; Participants had the opportunity to earn money for themselves by increasing their average steps per day.	Other: Offering a financial incentive to increase walking; After a baseline week of walking while wearing a pedometer, participants will be randomly assigned to one of the five conditions. In each of these conditions, participants will have the chance to earn .02/step for each additional step per day (on average across the week, above baseline levels). After a week of incentivized walking, participants will again be asked to wear the pedometer for one final week (with no incentive). Because the investigators need a week of walking before the incentive week, it is important that participants do not know the specific incentive aspect at the beginning of the study. Therefore, the investigators will not disclose the incentive structure at the beginning of the study. The investigators will debrief participants at the end of the study, and they will be fully informed of the purposes of the study at that time.
EXPERIMENTAL: Prosocial - loved one; Participants had the opportunity to earn money for a loved one of their choice by increasing their average steps per day.	Other: Offering a financial incentive to increase walking; After a baseline week of walking while wearing a pedometer, participants will be randomly assigned to one of the five conditions. In each of these conditions, participants will have the chance to earn .02/step for each additional step per day (on average across the week, above baseline levels). After a week of incentivized walking, participants will again be asked to wear the pedometer for one final week (with no incentive). Because the investigators need a week of walking before the incentive week, it is important that participants do not know the specific incentive aspect at the beginning of the study. Therefore, the investigators will not disclose the incentive structure at the beginning of the study. The investigators will debrief participants at the end of the study, and they will be fully informed of the purposes of the study at that time.
EXPERIMENTAL: Prosocial - charity; Participants had the opportunity to earn money for a charity of their choice by increasing their average steps per day.	Other: Offering a financial incentive to increase walking; After a baseline week of walking while wearing a pedometer, participants will be randomly assigned to one of the five conditions. In each of these conditions, participants will have the chance to earn .02/step for each additional step per day (on average across the week, above baseline levels). After a week of incentivized walking, participants will again be asked to wear the pedometer for one final week (with no incentive). Because the investigators need a week of walking before the incentive week, it is important that participants do not know the specific incentive aspect at the beginning of the study. Therefore, the investigators will not disclose the incentive structure at the beginning of the study. The investigators will debrief participants at the end of the study, and they will be fully informed of the purposes of the study at that time.
EXPERIMENTAL: Choice; Participants were given the choice to earn money either for themselves, a loved one, or a charity by increasing their average steps per day.	Other: Offering a financial incentive to increase walking; After a baseline week of walking while wearing a pedometer, participants will be randomly assigned to one of the five conditions. In each of these conditions, participants will have the chance to earn .02/step for each additional step per day (on average across the week, above baseline levels). After a week of incentivized walking, participants will again be asked to wear the pedometer for one final week (with no incentive). Because the investigators need a week of walking before the incentive week, it is important that participants do not know the specific incentive aspect at the beginning of the study. Therefore, the investigators will not disclose the incentive structure at the beginning of the study. The investigators will debrief participants at the end of the study, and they will be fully informed of the purposes of the study at that time.
NO_INTERVENTION: Control; Participants were not offered a financial incentive to increase their average steps per day. They simply wore the pedometer for three weeks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in average steps per day	Difference in average steps per day (from baseline week to incentive week)	Step count is measured via pedometer every day for three weeks

Collaborators and Investigators

• Sponsor: Stanford University
• Collaborators: National Institutes of Health (NIH)
• Investigators: Principal Investigator: Laura L Carstensen, PhD, Stanford University

Publications and helpful links

General Publications

• Carstensen LL. The influence of a sense of time on human development. Science. 2006 Jun 30;312(5782):1913-5. doi: 10.1126/science.1127488.
• Lockenhoff CE, Carstensen LL. Aging, emotion, and health-related decision strategies: motivational manipulations can reduce age differences. Psychol Aging. 2007 Mar;22(1):134-146. doi: 10.1037/0882-7974.22.1.134.
• Mikels JA, Lockenhoff CE, Maglio SJ, Goldstein MK, Garber A, Carstensen LL. Following your heart or your head: focusing on emotions versus information differentially influences the decisions of younger and older adults. J Exp Psychol Appl. 2010 Mar;16(1):87-95. doi: 10.1037/a0018500. Erratum In: J Exp Psychol Appl. 2010 Jun;16(2):157.
• Notthoff N, Carstensen LL. Positive messaging promotes walking in older adults. Psychol Aging. 2014 Jun;29(2):329-341. doi: 10.1037/a0036748.
• Anik L, Aknin LB, Norton MI, Dunn EW, Quoidbach J. Prosocial bonuses increase employee satisfaction and team performance. PLoS One. 2013 Sep 18;8(9):e75509. doi: 10.1371/journal.pone.0075509. eCollection 2013.
• Dunn EW, Aknin LB, Norton MI. Spending money on others promotes happiness. Science. 2008 Mar 21;319(5870):1687-8. doi: 10.1126/science.1150952. Erratum In: Science. 2009 May 29;324(5931):1143.
• Scott A, Schurer S. Financial incentives, personal responsibility and prevention. Discussion paper comissioned by the National Health and Hospitals Reform Commission. 2008. Retrieved from: http://www.health.gov.au/internet/nhhrc/publishing.nsf/Content/discussion-papers
• Raposo S, Hogan CL, Barnes JT, Chemudupati T, Carstensen LL. Leveraging goals to incentivize healthful behaviors across adulthood. Psychol Aging. 2021 Feb;36(1):57-68. doi: 10.1037/pag0000428. Epub 2020 Jul 6.

Study record dates

Study Major Dates

• Study Start: September 1, 2013
• Primary Completion (ACTUAL): March 1, 2017
• Study Completion (ACTUAL): March 1, 2017

Study Registration Dates

• First Submitted: January 27, 2017
• First Submitted That Met QC Criteria: January 30, 2017
• First Posted (ESTIMATE): January 31, 2017

Study Record Updates

• Last Update Posted (ACTUAL): April 28, 2017
• Last Update Submitted That Met QC Criteria: April 26, 2017
• Last Verified: April 1, 2017

More Information

Terms related to this study

• Keywords: physical activity; walking; incentive; step count
• Other Study ID Numbers: IRB-28280

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: The researchers will share de-identified participant data with other researchers.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No