Cultivating Gratitude: Does Manipulating Expectations Improve the Efficacy of a Gratitude Intervention?
Phase: NA
Conditions: Gratitude + No Expectations, Gratitude + Expectations, Events Control
Sponsor: University of California, Los Angeles

 
 
 
Study Protocol and Statistical Analysis Plan: Cultivating Gratitude: Does Manipulating 
Expectations Improve the Efficacy of a Gratitude Intervention?  
NCT03784001  
January 10, 2019 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Cultivating Gratitude: Does Manipulating Expectations Improve the Efficacy of a Gratitude 
Intervention?  
Interventions designed to elicit gratitude, an emotion expressed when one feels they have 
received something beneficial from other people or entities (Emmons & McCullough, 2003), 
have been shown to positively affect psychological and physical well-being. In previous studies, 
participants instructed to cultivate feelings of gratitude reported reductions in stress (i.e., 
O’Leary & Dockray, 2015) and increases in life satisfaction (e.g., Emmons & McCullough, 
2003, study 1; Froh, Sefick, & Emmons, 2008; Khanna & Singh, 2016; and Gilek, 2010; Kerr, 
O’Donovan, & Pepping, 2015), positive mood (e.g., Emmons & McCullough, 2003, study 2; 
Martínez-Martí, Avia, & Hernández-Lloreda, 2010; Khanna & Singh, 2016; and Froh et al., 
2014, study 2), and well-being (e.g., Khanna & Singh, 2016; Deng et al., 2019; and Jachowska, 
Brown, Ronaldson, & Steptoe, 2015) (e.g. Froh, Sefick, & Emmons, 2008; Emmons & 
McCullough, 2003; Watkins, Woodward, Stone, & Kolts, 2003, study 3, study 4). Though 
gratitude interventions are widely used, there are very few studies that examine whether small 
additions to methodology can enhance the effectiveness of these interventions. Drawing from 
literature on mindset and the placebo effect, we hypothesized that ​providing participants with 
information about the positive effects of previous gratitude interventions would improve their 
well-being, mood, and sleep after participating in a gratitude intervention. 
The majority of randomized controlled trials (RCTs) designed to cultivate gratitude 
report beneficial outcomes, though these effects are typically small. Evidence from studies on 
mindset and expectations suggest that these effects may be enhanced, though few studies have 
tested this.   Research on mindset - conscious or embodied expectation (Crum, Leibowitz, & 

Verghese, 2017)- and the placebo effect indicates that individuals may experience greater health 
improvements when they know the benefits of a job or activity (e.g., Crum & Langer, 2007; 
Desharnais, Jobin, Côté, Lévesque, & Godin, 1993). In one  study, for example, hotel maids who 
were told how many calories each of their job tasks burned and informed that their work met the 
requirements for good exercise and an active lifestyle exhibited significant health 
improvements--reduced weight, blood pressure, and body fat--when compared to hotel maids 
who were not provided with this information (Crum & Langer, 2007). In another study, 
participants who were told that an exercise program was meant to improve psychological 
well-being showed significant improvements in well-being relative to uninformed participants 
(Desharnais, Jobin, Côté, Lévesque, & Godin, 1993).  These studies suggest that knowing the 
benefits of an activity beforehand can enhance beneficial effects.  
Indeed, motivation and participant engagement are important factors in intervention 
efficacy (Lyubomirsky & Layous, 2013). Being motivated to first begin, and then continue to put 
effort into, a positive intervention can enhance intervention benefits. Participants who chose to 
engage in (and actually received) a “happiness” intervention (either promoting optimism or 
gratitude) experienced the greatest increases in happiness; of those receiving a happiness 
intervention, participants who put the most effort into their intervention’s exercises had the 
greatest gains in well-being (Lyubomirsky, Dickerhoof, Boehm, & Sheldon, 2011). Similarly, 
there is some evidence that reading encouraging information about an intervention improved 
outcomes. In an intervention in which the experimental conditions wrote about their best possible 
selves - their goals in different domains of life - participants who read peer testimonies about the 
effectiveness of the intervention had greater improvements in well-being than participants who 

read unrelated testimonies and participants in the control condition (Layous, Nelson, & 
Lyubomirsky, 2012). 
To our knowledge, only two gratitude interventions have tested outcome differences 
between informed (of benefits of gratitude interventions) versus not informed conditions. In one 
intervention, one gratitude condition was assigned to read fake articles about gratitude practices 
being effective. These participants experienced decreased well-being (at post-intervention), then 
increased well-being (at a three-week follow-up) compared to participants who read articles 
about gratitude practices being ineffective (Sin, Della Porta, & Lyubomirsky, 2011). These 
results do not clearly indicate if it is beneficial to advertise intervention efficacy, and utilized 
fake testimonies for encouragement. Harbaugh and Vasey (2014) had one gratitude condition 
read a short paragraph explaining the rationale for the intervention which concluded with the 
statement, “Filling out the following questionnaire is expected to have a positive effect on your 
well-being”. Participants were shown this rationale at the beginning of their instructions for 
every writing session, but did not experience better outcomes than the gratitude condition not 
shown the rationale (Harbaugh & Vasey, 2014). This finding may indicate that providing 
encouraging information about gratitude does not enhance intervention effectiveness. However, 
informed participants in Harbaugh and Vasey (2014) were only told one general benefit of 
gratitude. The present study told participants six specific, favorable outcomes from past gratitude 
studies. This design was intended to remind participants of intervention benefits each time they 
made a gratitude list, and was predicted to significantly improve participant’s outcomes.  
The present study sought to determine whether telling participants the benefits of 
gratitude exercises would improve the effectiveness of a two-week gratitude intervention. 

Participants were randomized to one of three conditions: gratitude + expectations (GE), gratitude 
+ no expectations (GNE), or events control. Participants in the GE condition were shown a 
beneficial outcome from a past gratitude study each time they made a gratitude list; those in the 
GNE condition were not. Based on studies in which participants experienced improved health 
and well-being when they knew the benefits of an activity (e.g., Crum & Langer, 2007; 
Desharnais, Jobin, Côté, Lévesque, & Godin, 1993), we hypothesized that participants in the GE 
condition would experience the greatest improvements in outcomes. Our primary outcome was 
well-being and our secondary outcomes were positive affect, sleep quality, sleep quantity, 
gratitude, stress, and depressive symptoms. We hypothesized that, compared to the control and 
GNE conditions, (1) the GE condition would report the greatest increases in hedonic, 
eudaimonic, and overall well-being and (2) the GE condition would report the greatest gains in 
positive affect, sleep quality, sleep quantity, and gratitude, and the greatest reductions in stress 
and depressive symptoms.  
Method 
Participants and Procedure 
Participants were recruited from an undergraduate psychology class at a large, public 
university. Inclusion criteria were being 18 years or older and having access to an email account. 
The study was announced to all 197 students in-person by the professor and via email. Study 
participation was offered as an alternative to completing one of the six class writing assignments, 
which were of comparable effort and time investment to study activities. All students were 
emailed a study information sheet. Students had to affirm that they met inclusion criteria and 
electronically sign and date the information sheet to enroll in the study. One hundred and 

twenty-nine participants elected to enroll in the study by submitting a signed information sheet. 
All study procedures were approved by the University of California, Los Angeles Institutional 
Review Board and consent was obtained from participants. The ClinicalTrials.gov identifier for 
this trial is NCT03784001.  
Participants were randomly assigned to one of the three conditions (GNE, GE, or events 
control) using a random number generator. On the first day of the study, participants received a 
baseline questionnaire via email. After completing their baseline questionnaire, participants were 
prompted to an online form, with instructions to type a short list, specific to the condition they 
were in (see ​Interventions​ below for more information). Every two days, participants were 
emailed a link to a new condition-specific online form. In total, participants were instructed to 
complete six condition-specific lists. Participants were emailed their post-intervention 
questionnaire two weeks after they received their baseline questionnaire. Participants received a 
reminder email to complete their baseline and post-intervention questionnaire if they did not 
complete either questionnaire one day after dissemination.  
Interventions 
Participants received an email with a link to each list, sent two days after completion of 
the previous list. GNE participants were instructed to list up to five things they were grateful for; 
GE participants were shown positive findings from gratitude RCTs and were instructed to list up 
to five things they were grateful for. Participants in the events control condition were instructed 
to list up to five events they engaged in that day.  
Both gratitude conditions (GNE and GE) were given the following instructions, adapted from 
Emmons and McCullough (2003) and Sheldon and Lyubomirsky (2006):  

You have been randomly assigned to try to cultivate a sense of gratitude now, and during the 
next few weeks. There are many things in our lives, both large and small, that we might be 
grateful about. These might include particular supportive relationships, sacrifices or 
contributions that others have made for you, facts about your life such as your advantages 
and opportunities, or even gratitude for life itself, and the world that we live in. Think back 
over the past day and, on the lines below, type up to five things in your life that you are 
grateful or thankful for. 
GE participants were also shown a beneficial finding about gratitude on each of their 
questionnaires, immediately before they made their gratitude list. Some of the beneficial findings 
included: “​Undergraduates who practiced gratitude had higher expectations for the upcoming 
week (Emmons & McCullough, 2003, Study 1)” and “Gratitude contemplation can decrease 
body dissatisfaction and increase body esteem (Wolfe & Patterson, 2017)”. 
Participants in the events condition were given the following instructions:  
You have been randomly assigned to write about your daily events now and over the next two 
weeks. Throughout a day, we may engage in many different events. These might include 
classes you had today, conversations you had, or activities you engaged in such as studying 
for a test or eating a meal. Many events happen throughout a day. Think back over your 
activities today and, in the space below, type up to five things or events you remember from 
today. 
Measures 
Demographic characteristics. ​Demographic variables - age, sex race, year in school, 
major, relaitonship status, and family income - were assessed at baseline. 

Primary outcomes. ​Hedonic well-being, eudaimonic well-being, and overall well-being 
were assessed at baseline and post-intervention. Well-being was measured with the Mental 
Health Continuum-Short Form (MHC-SF; Keyes, 2009). Participants rated how often they felt 
14 different emotions or statements, such as “happy” and “satisfied with life”. Items are rated on 
a 6-point likert scale (0 = ​never​, 5 = ​everyday​), with higher numbers indicating greater 
well-being. This measure assesses both hedonic and eudaimonic well-being. The MHC-SF is 
both reliable and valid for use with young adults (Robitschek & Keyes, 2009)  .  
Secondary outcomes. ​Positive affect, sleep quality, sleep quantity, gratitude, and the 
greatest reductions in stress and depressive symptoms were assessed at baseline and 
post-intervention.  
Statistical Analysis Plan 
Differences in demographic variables were assessed using one-way Analysis of Variance 
(ANOVA) and chi-squared tests to examine baseline differences between groups. Next, for each 
primary (i.e., well-being) and secondary outcome (i.e., positive affect, sleep quality) we ran 
separate repeated measures ANOVAs using SPSS. Differences in change over time between 
groups were assessed using the time-by-condition interaction term, which tells us whether groups 
differed over time for each outcome. Post hoc analyses were then conducted to further 
investigate any significant interactions. Finally, to test if completing the gratitude exercises 
improved well-being, we combined the GE and GNE conditions to create a combined gratitude 
(CG) group which we compared to the control condition. To do this, we ran separate repeated 
measures ANOVAs comparing the CG group to the control condition, looking at the 
time-by-condition interaction term for each outcome.