Do Positive Psychology Exercises Work? A Replication of
Seligman et al. (2005)
Myriam Mongrain and Tracy Anselmo-Matthews
Objectives: The current work replicated a landmark study conducted by Seligman and colleagues
(2005) that demonstrated the long-term beneﬁts of positive psychology exercises (PPEs). In the origi-
nal study, two exercises administered over 1 week (“Three Good Things” and “Using your Signature
Strengths in a New Way”) were found to have long-lasting effects on depression and happiness (Selig-
man, Steen, Park, & Peterson, 2005). Design: These exercises were tested here using the same
methodology except for improvements to the control condition, and the addition of a second “positive
placebo” to isolate the common factor of accessing positive, self-relevant constructs. This component
control design was meant to assess the effect of expectancies for success (expectancy control), as
well the cognitive access of positive information about the self (positive placebo). Results: Re-
peated measures analyses showed that the PPEs led to lasting increases in happiness, as did the
positive placebo. The PPEs did not exceed the control condition in producing changes in depression
over time. Conclusions: Brief, positive psychology interventions may boost happiness through a
common factor involving the activation of positive, self-relevant information rather than through other
speciﬁc mechanisms. Finally, the effects of PPEs on depression may be more modest than previously
assumed. C2012 Wiley Periodicals, Inc. J. Clin. Psychol. 68:382–389, 2012.
Keywords: positive psychology exercises; signature strengths; three good things; depression; happi-
ness; e-mental health
Positive psychology is the study of positive experiences, positive character traits, and the in-
stitutions that help cultivate them (Seligman, 2011). Its proponents argue that the movement
has embraced the most rigorous scientiﬁc approach in the study of positive human experi-
ence, and research has proliferated capturing the attention of thousands of scientists (Seligman
et al., 2005; Simonton & Baumeister, 2005; Seligman, 2011). Positive psychotherapy is now
emerging as a new form of intervention, pitting itself against established therapy approaches
(Seligman, Rashid, & Parks, 2006; Wood & Tarrier, 2010). The techniques espoused by positive
psychologists must be held to the same level of scrutiny and accountability as the more tradi-
tional forms of intervention. As stated by Seligman (2011), positive psychology should teach
people effective pathways to improved functioning and well-being.
The current work takes a critical look at a landmark study conducted by Seligman and
colleagues (2005) documenting the efﬁcacy of positive psychology exercises (PPEs). They tested
happiness interventions via the Internet with a convenience sample of 411 participants using
a random assignment, placebo control design. The happiness interventions comprised daily
exercises performed over a 1-week period. The placebo control involved writing about early
memories every night for a week. The two most effective exercises included (a) “Three good
things in life,” in which participants were asked to write three good things that happened
that day and why they happened, and (b) “Using signature strengths in a new way,” in which
participants took an online inventory of their character strengths which provided feedback about
their top ﬁve strengths as catalogued by Peterson and Seligman (2004). Participants were then
asked to use one of those strengths in a new and different way every day for 7 days.
Seligman et al. (2005) collected information on happiness and depressive symptoms at pretest,
posttest, 1 week, 1 month, 3 months, and 6 months after the administration of these interventions.
Correspondence concerning this article should be addressed to: Myriam Mongrain, 4700 Keele
St., Toronto, Ontario, Canada, M3 J1 P3; e-mail: firstname.lastname@example.org
JOURNAL OF CLINICAL PSYCHOLOGY, Vol. 68(4), 382–389 (2012) C2012 Wiley Periodicals, Inc.
Published online in Wiley Online Library (wileyonlinelibrary.com/journal/jclp). DOI: 10.1002/jclp.21839
Replication of Seligman et al. (2005) 383
The “Three good things” and “Using signature strengths in a new way” conditions led to
particularly positive results when the changes in mood were considered over a longer period of
time. For both interventions, differences in levels of depression and happiness were evident at the
1-month, 3-month, and 6-month assessments when compared with the early memory control
condition. These two positive psychology exercises (PPEs) were included for replication in the
The aim of the current study was to replicate these results while enhancing the scientiﬁc rigor
of the work by Seligman and colleagues (2005). The same methodology was employed except
for modiﬁcations to the early memory control condition. A more convincing rationale as to why
this exercise may improve well-being was included to match the rationales of the “The three
good things” and “Using signature strengths in a new way” exercises. Termed the “expectancy
control,” this exercise involved an argument for how reﬂecting on the past, even for a short period
of time, can increase understanding, self-acceptance, and happiness. This change was designed
to control for a “common factor” (Frank & Frank, 1991) in PPEs involving high expectancies
for success. If the PPEs failed to outperform this control condition, then their effects could be
attributed to the manipulation of belief in positive change.
As found in component control designs in psychotherapy research (Haaga & Stiles, 2000), the
“therapeutic ingredients” in PPEs were dismantled further by isolating a common component
involving the access of positive, self-relevant information. A “positive placebo” was created
identical to the ﬁrst control exercise, except that positive memories about one’s life had to be
retrieved. The role of this positive placebo was to assess whether there was anything “special”
about the PPEs other than the access of positive self-representations. These group comparisons
appeared critical in light of a concluding statement made by Seligman et al. (2005): “The ﬁnding
of beneﬁcial effects [of PPEs] with no human therapeutic alliance suggests the operation of
powerful speciﬁc ingredients in the exercises” (Seligman et al., 2005, p. 420). The main purpose of
the current work was to test whether those exercises, now incorporated in positive psychotherapy
(Rashid & Seligman, 2011), involved speciﬁc ingredients responsible for increasing well-being
rather than a common focus on positive aspects of one’s self and one’s life.
In short, this study attempted to add to the body of research on positive interventions by ﬁrst
replicating the effects reported by Seligman et al. (2005). In addition, the demand characteristics
of the original control exercise were improved, and a second positive placebo was added to
test for the effects of accessing positive information about the self. The main hypothesis was
that the PPEs (“Using signature strengths in a new way” and “Three good things”) would be
associated with increases in happiness and decreases in depressive symptoms relative to both
placebo groups over 6 months, replicating the ﬁndings of Seligman and colleagues (2005). Both
control groups (early, and early positive memories) were expected to provide temporary boosts
in mood that would dissipate over time because they did not involve any speciﬁc “therapeutic”
The initial sample comprised 1,447 primarily White (78%), Canadian (84%) females (83%).
Participant ages ranged from 18 to 72 years, with a mean of 33. Participants were recruited
primarily through advertisements on Facebook, with an ad stating: “Feel better: Participate
in Project HOPE (Harnessing One’s Personal Excellence).” The advertisements appeared to
Canadian users over 18 years of age.
In terms of demographics, 64% of participants had some college or university education, with
40% earning under $20,000 a year and 23% earning over $50,000. Thirty percent of participants
were married and 44% percent had children. As a whole, the sample had clinically signiﬁ-
cant levels of depressive symptomatology (Center for Epidemiologic Studies Depression Scale
[CES-D] measure of depression, ¯
x=20.39, s =14.62, which is above the cut-off for mild
x=16; Geisser, Roth, & Robinson, 1997).
384 Journal of Clinical Psychology, April 2012
Participant remuneration.Participants who registered for the study before November
1, 2007, received $30 remuneration upon completion of the posttest measures administered at
1 week (55% received remuneration). To manage costs while increasing sample size, participants
registering after this date were not offered $30 but were entered into a $1,000 draw upon com-
pletion of the posttest measures. To encourage participation in subsequent follow-up sessions,
all participants were entered in a $1,000 rafﬂe at each follow-up. The incentives in the current
study were slightly higher than those provided by Seligman and colleagues (2005), who offered
one $500 and three $100 awards at each follow-up.
Steen Happiness Index (SHI).The SHI was created and utilized by Seligman et al.
(2005) to serve as a measure of happiness that might be particularly sensitive to upward changes
in happiness (Seligman et al., 2005; Duckworth, Steen, & Seligman, 2005). The index comprises
20 items that require the participant to choose from one of ﬁve statements that most closely
reﬂects how they have felt over the past week. Scores on this scale were found to be highly
correlated with other measures of happiness and to have an internal consistency of α=.95 and
a test-retest reliability of .97 over 1 week (Seligman et al., 2005).
CES-D.The CES-D (Radloff, 1977; also utilized in Seligman et al., 2005) is a widely used
20-item inventory designed to measure the incidence of depressive symptoms over the prior week.
Each symptom is rated in terms of frequency on a 5-point Likert scale, ranging from 0 (less than
1 day) to 4 (most or all of the time). Much research has illustrated the good internal consistency,
reliability, convergent and concurrent validity, and sensitivity of this measure (Santor, Zuroff,
Ramsay, Cervantes, & Palacios, 1995). Internal consistency has been reliably found to be excellent
in a wide variety of samples (Corcoran & Fisher, 1987; Radloff, 1977).
The measures and design of the study were identical to that of Seligman et al. (2005).
Participants were asked to log onto the website for the study entitled Project HOPE at
www.projecthopecanada.com. Participants then completed a battery of tests including base-
line measures of happiness (SHI) and current depressive symptoms (CES-D) and then were
randomly assigned to one of four conditions. Segments of the rationales for each condition are
rExpectancy control (early memories): “‘The unexamined life is not worth living (Socrates).’
The importance of self-knowledge and understanding has long been recognized. We believe
that a strong sense of self and an understanding of the factors that have come to make you
the person you are today are essential components of well-being. Our early life experiences
can inﬂuence us and play a role in how we think and act later on in our lives. It may be
important to reﬂect upon these early experiences to gain a better understanding of the person
we are today. Every night over the next week, set aside about 10 minutes before bed to do this
exercise. It will require you to log on to this website to write about an early memory.”
rPositive placebo (positive early memories, in addition to rationale above): “A careful consid-
eration of our past may help us to better understand who we are today and ultimately lead to
increased self-acceptance and well-being, particularly when we focus on the positive aspects.
Every night over the next week, set aside about 10 minutes before bed to do this exercise. It
will require you to log on to this website to write about an early positive memory.”
rThree good things (Seligman et al., 2005): “We think too much about what goes wrong and
not enough about what goes right in our lives. Of course, sometimes it makes sense for us to
analyse bad events so that we can learn from them and avoid them in the future. However,
people tend to spend more time thinking about what is bad in life than is helpful. Worse, this
tendency to focus on bad events sets us up for anxiety and depression. One way to keep this
from happening is to develop our ability to think about the good in life. In order to help you
Replication of Seligman et al. (2005) 385
build this skill you will be asked to log on to the website daily for seven days to list three
things that went well on that day and why they happened.”
rUsing signature strengths in a new way (Seligman et al., 2005): “Honesty. Loyalty. Persever-
ance. Creativity. Kindness. Wisdom. Courage. Fairness. These and about 16 other character
strengths are valued in almost every culture in the world. We believe that people can get more
satisfaction out of life if they learn to identify which of these character strengths they possess
in abundance and then use them as much as possible whether working, loving, or playing.
This exercise consists of two parts. You will take a questionnaire that gives you feedback
about your strengths. This will take about 45 minutes. The next day you will be asked to use
these strengths in new ways every day for one week and to report back to us each day to
describe how you did so.”
All exercises included a requirement of approximately 10 minutes a day and all stated the same
expectancy priming: “The beneﬁts of this work may not be immediate, but like exercising, the
advantages can emerge over time with continued practice”. At the conclusion of the week-long
exercise period, participants completed outcome measures including the CES-D and the SHI.
Participants were also sent reminder e-mails for their 1-month, 3-month, and 6-month online
follow-up assessments including the CES-D and the SHI.
There were a total of 1,447 participants who ﬁlled out the initial questionnaires and were assigned
to an exercise condition. Of these, 344 (24%) completed all the requirements of the study,
including the 6-month follow-up. ttests show that those who dropped out by 6 months were, at
baseline, more depressed, CES-D; t(1444) =2.07, p=.04, and less happy, SHI; t(1444) =−3.66,
p<.001. Drop-out rates did not differ signiﬁcantly by condition, χ2(3) =4.77, p=.19.
Replication of Seligman et al. (2005)
Happiness.The analyses in Seligman et al. (2005) involved repeated measures analyses of
variance (ANOVAs) that were replicated here to determine whether “Three good things” and
“Using signature strengths in a new way” were effective in increasing happiness levels over the
6-month study period over and above the control conditions. Participants who completed test
measures at all ﬁve time points were included.1
An overall repeated measures ANOVA was conducted (four conditions by ﬁve time peri-
ods) for the happiness measure (SHI).2A signiﬁcant main effect for time was found, F(4,
1A drawback of the repeated ANOVA statistic is that participants with missing data points are excluded,
which is particularly problematic given our high attrition rate. Multilevel modeling, conducted in SAS
and using maximum likelihood estimation was performed as a sensitivity test. The models were run on
participants who provided data at baseline and 1 week (n=960) to preserve a more balanced data set
and produce reliable estimates. Payment for participation and demographic variables including age, gender,
income, education, as well as adherence (number of nights the exercises were completed) were included in the
models to determine their potential inﬂuence on outcome. All groups, including “Early positive memories”
(estimate =.03, standard error [SE]=.01, t=2.82, p=.005), “Three good things” (estimate =.03,
SE =.01, t=2.68, p=.007), and “Using signature strengths in a new way” (estimate =.03, SE =.01,
t=2.21, p=.03), were related to higher rates of change in happiness compared with the expectancy control
group. The PPEs were not signiﬁcantly different from the positive placebo. The “Three good things” exercise
was marginally associated with greater reductions in depression when compared with the “Early memories”
control group (estimate =−.46, SE =.25, t=−1.87, p=.06), but not compared with the positive placebo
(estimate =−.14, SE =.24, t=−.57, p=.57). These results mirror those obtained with the repeated
measures ANOVAs presented in the text.
2Eleven participants failed to complete the SHI, explaining the differences in the degrees of freedom for the
happiness and depression analyses.
386 Journal of Clinical Psychology, April 2012
Figure 1. Average happiness scores on the SHI over the 6-month study period.
Note. Effect sizes are noted where means differed signiﬁcantly from baseline (p <.05).
337) =8.53, p<.001, ηp
2=.092, indicating that participants increased in self-reported levels
of happiness over time. A signiﬁcant time by condition interaction was also obtained, F(12,
1017) =2.35, p=.006, ηp
2=.027, showing varying changes in happiness over time among the
Planned contrasts were conducted comparing happiness scores at each follow-up to baseline
scores within each group. Participants in the expectancy control group tended to increase in
happiness at 1 week (p=.07, d=.10), but returned to baseline at the 1-month, 3-month,
and 6-month follow-ups (ps >.10; see Figure 1). Thus, as expected, the control condition may
have boosted mood initially due to expectancy effects, but did not lead to any lasting change
in happiness. The “Early positive memories” placebo condition showed signiﬁcant increases in
happiness at 1 month (p<.001, d=.27), 3 months (p=.001, d=25), and 6 months (p=.01,
d=20; see Figure 1). Thus, our results indicate that our positive placebo was associated with
lasting gains in happiness.
For “Three good things,” happiness increased signiﬁcantly at 1 week (p=.004, d=.15), and
continued to be elevated at the 3-month (p=.001, d=.22) and 6-month (p=.02, d=.16)
follow-ups (see Figure 1). For “Using signature strengths in a new way,” happiness signiﬁcantly
increased compared with baseline levels at 1 week (p<.001, d=.29), 1 month (p=.03, d=.16),
and at 6 months (p=.01, d=.24; see Figure 1). In summary, the Seligman and colleagues
(2005) ﬁndings for happiness were mostly replicated, and the PPEs surpassed the effect of the
expectancy control group, but not the positive placebo.
Depressive Symptoms.Parallel analyses were conducted with depressive symptoms to
determine how exercises may have affected depression over time. An overall repeated mea-
sures ANOVA was conducted (four conditions by ﬁve time points) with the CES-D as the
outcome measure. Participants evidenced signiﬁcant decreases in depressive symptoms over the
6-month study, effect for time, F(4, 348) =4.57, p=.001, ηp
2=.050. However, contrary to
the ﬁndings obtained by Seligman et al., (2005), there was no time by condition interaction
effect, F(12, 1050) =1.48, p=.13, indicating that changes in the CES-D did not differ across
Replication of Seligman et al. (2005) 387
Replication of Seligman et al. (2005)
A science builds itself on tests of replicability. Seligman and colleagues (2005) previously
reported impressive ﬁndings that demonstrated the effectiveness of positive psychology exercises
in increasing levels of happiness and decreasing depression over a period of 6 months. Our
methodology was identical, but utilized more powerful placebos and yielded results that were
more modest. The PPEs produced greater increases in happiness compared with the expectancy
control condition, conﬁrming that their effectiveness cannot be reduced to the creation of
“high hopes.” But the positive placebo (positive early memories) produced effects that were
as signiﬁcant and as long lasting as those of the “Three good things” and “Using signature
strengths in a new way” exercises. We may have serendipitously stumbled upon another effective
exercise with its own speciﬁc ingredients, but we prefer to believe that the access of positive,
self-relevant information is the common factor with the largest “therapeutic” effect shared with
the other PPEs.
In sharp contrast to the ﬁndings reported by Seligman and colleagues (2005), the PPEs did
not lead to signiﬁcantly greater reductions in depression over time compared with the control
group. The difference in our ﬁndings may be attributable to differences in control groups. The
rationale in the expectancy control condition provided a credibleexplanation for success that may
have narrowed the gap between groups over time. Furthermore, our participants were slightly
more depressed than those in Seligman et al. (2005), and may have been lower functioning.3
Another possible explanation for the more glowing results reported by Seligman and colleagues
(2005) lies in their sample recruited through Seligman’s self-help book Authentic Happiness
(2002). This select group may have had higher levels of motivation, greater interest, and belief
in positive psychology exercises. This possibility is supported by the fact that the drop-out rate
for participants in Seligman and colleagues (2005) was much lower (29%) than the one in the
current study (76%).
Much of what is effective in psychotherapy is attributable to common factors, while speciﬁc
techniques account for about 15% of improvement (Asay & Lambert, 1999). It may be useful
for positive psychologists to draw from this foundation, and moderate some conclusions. For
example, Seligman et al. (2005) state: “Identifying speciﬁc ingredients is an uncommon early
move in the testing of interventions (PPEs), and our studies go beyond such demonstrations”
(p. 419). We obtained little or no difference between the “Three good things,” “Using signature
strengths in a new way,” and the positive placebo exercise. We could not demonstrate the unique
qualities or speciﬁc ingredients belonging to PPEs exclusively. Furthermore, “client factors”
(Asay & Lambert, 1999) must be taken into consideration for the results obtained by Seligman
et al. (2005) and us. Both samples involved people who wanted to become happier, had access
to books and Internet resources, and were interested in online self-help. This client factor makes
the generalization to other populations difﬁcult.
Summary and Future Directions
Some criticisms have been targeted at the placebo controls in positive psychology research and
the potentially premature conclusions drawn around the efﬁcacy of some interventions (Wood &
Tarrier, 2010). Our design allowed us to partial out expectancy effects, and the results suggest that
PPEs do more than provide belief in change when it comes to self-reported levels of happiness.
Our design also allowed for further consideration of the common component that may underlie
the effectiveness of PPEs. The access of positive aspects of the self-schema may be a common
feature shared across the PPEs and the positive placebo in this study. Perhaps thinking positively
about your past, your day, or your strengths activates the natural growth potential in individuals
(Tallman & Bohart, 1999) and may well mobilize hope by providing tools that bolster optimism
3The average CES-D score in Seligman et al. (2005) hovered around 14, while the average score in the current
sample was 20.4.
388 Journal of Clinical Psychology, April 2012
Means for Happiness and Depression Across Conditions and Across Time
Baseline 1 week 1 month 3 months 6 months
Early memories (n=81) x=2.75, s=.81 x=2.84, s=.83 x=2.80, s =.86 x=2.80, s=.85 x=2.70, s=.88
Early positive memories (n=87) x=2.74, s=.72 x=2.82, s=.76 x=2.93, s=.75 x=2.92, s=.76 x=2.89, s=.85
3 good things (n=102) x=2.76, s=.78 x=2.88, s=.81 x=2.80, s =.83 x=2.94, s=.82 x=2.89, s=.87
Signature strengths (n=74) x=2.75, s=.65 x=2.94, s=.72 x=2.86, s=.76 x=2.86, s=.75 x=2.91, s=.74
Early memories (n=84) x=19.61, s=.14.44 x=18.80, s=13.49 x=19.93, s=14.02 x=20.45, s=14.79 x=20.04, s=14.90
Early positive memories (n=90) x=19.19, s=14.05 x=17.19, s=13.13 x=15.84, s=12.55 x=17.14, s=12.91 x=17.67, s=14.34
3 good things (n=106) x=19.47, s=.14.41 x=15.66, s=11.59 x=18.57, s=12.64 x=16.47, s=11.84 x=16.56, s=14.90
Signature strengths (n=75) x=17.73, s=.14.50 x=14.99, s=13.10 x=16.81, s=14.06 x=14.28, s=11.93 x=15.69, s=14.82
Note. SHI =Steen Happiness Index (Seligman et al., 2005). CES-D =Center for Epidemiologic Studies Depression Scale (Radloff, 1977).
Replication of Seligman et al. (2005) 389
and stimulate pathways toward change (Snyder, Ilardi, Michael, & Cheavens, 2000). It could also
activate positive emotions that are known to broaden cognition, leading to behavioural changes
and upward spirals in mood (Fredrickson, 2001; Garland et al., 2010). Future research on PPEs
should seek to elucidate the speciﬁc mechanisms responsible for improvements in mood and
ﬂourishing and explain how and why they work. This will be most fruitfully accomplished with
rigorous methodological designs and a guiding theory of psychological growth.
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