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Positive Psychology 1
Positive Psychology Progress:
Empirical Validation of Interventions
Martin E. P. Seligman & Tracy A. Steen
University of Pennsylvania
Nansook Park
University of Rhode Island
&
Christopher Peterson
University of Michigan
(final revision, April 22, 2005)
Abstract
Positive psychology has flourished in the last five years. We review its recent developments,
including books, meetings, courses, and conferences. We discuss the newly-created classification
of character strengths and virtues, a positive complement to the DSM’s, and we present some
cross cultural findings that suggest surprising ubiquity of strengths and virtues. Finally, we focus
on psychological interventions that increase individual happiness. In a six-group, random
assignment, placebo-controlled Internet study, we tested five purported happiness interventions
and one plausible control exercise. We found that three of the interventions lastingly increased
happiness and decreased depressive symptoms. Positive interventions can supplement traditional
interventions that relieve suffering and this may someday be the practical legacy of positive
psychology,
Positive Psychology 2
Positive Psychology Progress:
Empirical Validation of Interventions
Five years have passed since the American Psychologist devoted its millennial issue to
the emerging science of positive psychology: the study of positive emotion, positive character,
and positive institutions (Seligman & Csikszentmihalyi, 2000). Drawing on methods effectively
used to advance the science of mental disorders, positive psychologists have been studying
mental health and well-being. Building on pioneering work by Rogers (1951), Maslow (1954,
1962), Jahoda (1958), Erikson (1963, 1982), Vaillant (1977), Deci and Ryan (1985), and Ryff
and Singer (1996)—among many others—positive psychologists have enhanced our
understanding of how, why, and under what conditions positive emotions, positive character, and
the institutions that enable them flourish (e.g., Cameron, Dutton, & Quinn, 2003; Easterbrook,
2003; Gardner, Csikszentmihalyi, & Damon, 2001; Kahneman, Diener, & Schwarz, 1999;
Murray, 2003; Vaillant, 2000).
Positive psychologists do not claim to have invented the good life or to have ushered in
its scientific study, but the value of the overarching term positive psychology is to unite what had
been scattered and disparate lines of theory and research about what makes life most worth living
(Peterson & Park, 2003). As the basic science continues, other lines of work are moving into the
realm of application (Linley & Joseph, 2004). Can we take what we have learned about the
science and practice of mental illness and use it to create a practice of making people lastingly
happier? That is, can we create an evidence-based practice of positive psychology?
In this paper, we first review the recent growth within positive psychology. Next, we
describe basic research which bears on whether people can become lastingly happier and then
present the results of our own happiness interventions that we rigorously tested with a
randomized, placebo-controlled design.
Progress Report
Positive psychology is an umbrella term for the study of positive emotions, positive
character traits, and enabling institutions. Research findings from positive psychology are
intended to supplement, not remotely to replace, what is known about human suffering,
weakness, and disorder. The intent is to have a more complete and balanced scientific
understanding of the human experience—the peaks, the valleys, and everything in between. We
believe that a complete science and a complete practice of psychology would include an
understanding of suffering and happiness, as well as their interaction, and validated interventions
that both relieve suffering and increase happiness—two separable endeavors.
Books. In the last five years, aside from a special issue and a special section of the
American Psychologist (January 2000 and January 2001, respectively), literally hundreds of
articles on the topics have appeared in the scholarly and popular press. Books have begun to
appear. For example, see The Handbook of Positive Psychology (Snyder & Lopez, 2002),
Authentic Happiness (Seligman, 2002), A Psychology of Human Strengths (Aspinwall &
Staudinger, 2003), Flourishing (Keyes & Haidt, 2003), Positive Psychological Assessment: A
Handbook of Models and Measures (Lopez & Snyder, 2004), Positive Psychology in Practice
(Linley & Joseph, 2004), and Handbook of Methods in Positive Psychology (Ong & van Dulmen,
in press). These volumes summarize the empirical findings and the methods used in the science.
We want to highlight our own Character Strengths and Virtues: A Handbook and
Classification (“CSV”; Peterson & Seligman, 2004). The CSV represents the most ambitious
project self-consciously undertaken from the perspective of positive psychology, and it intends to
do for psychological well being what the Diagnostic and Statistical Manual of the American
Positive Psychology 3
Psychiatric Association (DSM; 1994) does for the psychological disorders that disable human
beings. The CSV describes and classifies strengths and virtues that enable human thriving.
Although respectful of the DSM, we attempted to avoid some of its problems by making clear
why some entries are included in the CSV and others excluded, by regarding positive traits as
individual differences that exist in degrees, rather than all-or-nothing categories, and by
developing reliable and valid assessment strategies (questionnaires, surveys, interviews, and
informant reports) (Peterson, Park, & Seligman, 2005).
The general scheme of the CSV relies on six overarching virtues that almost every culture
across the world endorses: wisdom, courage, humanity, justice, temperance, and transcendence
(Dahlsgaard, Peterson, & Seligman, 2005). Under each virtue, we identified particular strengths
that met the following criteria:
• ubiquity - is widely recognized across cultures
• fulfilling - contributes to individual fulfillment, satisfaction, and happiness broadly
construed
• morally valued - is valued in its own right and not as a means to an end
• does not diminish others - elevates others who witness it, producing admiration, not
jealousy
• nonfelicitous opposite - has obvious antonyms that are "negative"
• traitlike - is an individual difference with demonstrable generality and stability
• measurable - has been successfully measured by researchers as an individual
difference
• distinctiveness - is not redundant (conceptually or empirically) with other character
strengths
• paragons - is strikingly embodied in some individuals
• prodigies - is precociously shown by some children or youth
• selective absence - is missing altogether in some individuals
• institutions - is the deliberate target of societal practices and rituals that try to
cultivate it
Table 1 lays out the classification, which includes 24 strengths of character. While we avoid a
claim of universality, one of ubiquity seems warranted by the evidence below.
Each chapter in the CSV describes what is known and what is not known about each of
the included strengths: paradigm cases, consensual definition, historical and cross-cultural
background, measurement, correlations and consequences of having or lacking the strength,
development, enabling and disabling conditions, gender differences, and interventions that build
the strength. We intend this volume to be a framework for conducting future research and
creating new interventions.
Three surprising empirical findings have already emerged, First, we have discovered a
remarkable similarity in the relative endorsement of the 24 character strengths by adults around
the world and within the United States (Park, Peterson, & Seligman, 2005a). The most
commonly-endorsed (“most like me”) strengths, in 40 different countries, from Azerbaijan to
Venezuela, are kindness, fairness, authenticity, gratitude, and open-mindedness, and the lesser
strengths consistently include prudence, modesty, and self-regulation. The correlations of the
rankings from nation to nation are very strong, in the .80 range, defying cultural , ethnic, and
religious differences. The same ranking of greater versus lesser strengths characterizes all 50 US
states—except for religiousness, somewhat more evident in the south—and holds across gender,
age, red versus blue states, and education. Our results may reveal something about universal
human nature and/or the character requirements minimally needed for a viable society (cf. Bok,
Positive Psychology 4
1995).
Second, a comparison of strengths profiles between US adults and US adolescents
revealed overall agreement on ranking, yet a noticeably lower agreement than that found
between US adults and adults in any other nation we have studied (Park, Peterson, & Seligman,
2005b). Hope, teamwork, and zest were more common among US youth than US adults, whereas
appreciation of beauty, authenticity, leadership, and open-mindedness were more common
among adults. As our attention turns to the deliberate cultivation of character strengths, we
should be as concerned with how to keep certain strengths from eroding on the journey to
adulthood as well as with how to build others from scratch (Park & Peterson, in press b).
Third, although part of the definition of a character strength is that it contributes to
fulfillment, strengths “of the heart”-- zest, gratitude, hope, and love--are more robustly
associated with life satisfaction than the more cerebral strengths such as curiosity and love of
learning: (Park, Peterson, & Seligman, 2004). We find this pattern among adults and among
youth, as well as longitudinal evidence that these “heart” strengths foreshadow subsequent life
satisfaction (Park, Peterson, & Seligman, 2005b). One more finding to note: Self-regulation
among parents, while not strongly associated with parental life satisfaction, is positively linked
to the life satisfaction of their children (Park & Peterson, in press a).
Meetings, centers, and courses. Well-attended scholarly meetings occur regularly. For
example, in October 2004, over 390 positive psychologists from 23 countries attended the Third
Annual International Positive Psychology Summit in Washington, DC. The European Network
of Positive Psychology sponsored its second conference in July 2004 in Italy, attended by 300
people from all over the world. Young researchers apply to attend the annual summer Positive
Psychology Institute, a week-long program in which researchers early in their careers exchange
ideas and receive guidance from more senior figures in positive psychology. From May 15 to
June 30 of 2005, 2006, and 2007, Medici II will be held at the University of Pennsylvania:
dozens of scientists and scholars will gather to work together on five projects: (a) productivity
and health as a function of happiness; (b) national well-being indices; (c) spirituality and
successful aging; (d) psychological capital; and e) positive psychology websites in Chinese and
Spanish and ultimately all major language groups.
The Positive Psychology Network funds more than fifty research groups involving more
than a hundred and fifty scientists from universities all over the world. The first Positive
Psychology Centers (at the University of Pennsylvania, the University of Michigan, the
University of Illinois, and Claremont Graduate University) now exist.
Positive psychology courses at both the undergraduate and graduate levels are now
offered at several dozen US universities and in Europe, exposing students to the idea that it
makes sense to study what is right about people in addition to what is wrong. Martin Seligman
and Ben Dean offered a 48-hour telephone course, Authentic Happiness Coaching, on the
principles, tests, and interventions in Positive psychology. More than 1000 people participated,
including clinical and counseling psychologists, coaches, educators, psychiatrists, physicians,
and personnel managers. The first Master's degree will be offered by the University of
Pennsylvania, a Masters of Applied Positive Psychology, starting in September 2005. Within one
month of announcing the existence of the degree, over two hundred applications were filed.
Widespread dissemination of positive psychology research means that the general
psychological community is beginning to understand that respectable science can be done on the
positive side of life. Websites devoted to Positive Psychology are burgeoning, and some of the
most popular include: www.apa.org/science/positivepsy.html, www.bus.umich.edu/Positive/,
www.reflectivehappiness.com and www.positivepsychology.org/. A Positive Psychology
Listserv can joined at: www.positivepsychology.org/pospsy.htm#PP%20Listserve. There has
Positive Psychology 5
been strong media interest in positive psychology, with hundreds of newspaper and magazine
articles appearing all over the world. Time Magazine devoted its cover and almost its entire
January 17, 2005 issue to the scientific advances and practice implications of the field.
Funders have been generous. Atlantic Philanthropies, the Annenberg Foundation,
Sunnylands Trust, the Mayerson Foundation, the Templeton Foundation, the Hovey Foundation,
the Gallup Foundation, the U.S. Department of Education, and others have made substantial
grants to support the scientific research and the dissemination of the findings.
Interventions. We focus the rest of this article on the efficacy of psychological
interventions to increase individual happiness, in many ways the bottom line of work in positive
psychology. First, a caveat about the word happiness itself: We work under the assumption that
happiness is a scientifically unwieldy term and that its serious study involves dissolving the term
into at least three distinct and better-defined routes to "happiness" (Seligman, 2002): (a) positive
emotion and pleasure (the pleasant life); (b) engagement (the engaged life); and (c) meaning (the
meaningful life). Our recent research suggests that people reliably differ according to the type of
life that they pursue and further that the most satisfied people are those who orient their pursuits
toward all three, with the greatest weight carried by engagement and meaning (Peterson, Park, &
Seligman, in press). We continue to use the word happiness, but only in the atheoretical sense of
labeling the overall aim of the positive psychology endeavor and referring jointly to positive
emotion, engagement, and meaning.
One nonobvious reason to be interested in interventions that build happiness is that
happiness is not an epiphenomenon. An important fact that has emerged in the last few years is
that happiness is causal and brings many more benefits than just feeling good. Happy people are
healthier, more successful, and more socially engaged, and the causal direction runs both ways
(Lyubomirsky, King, & Diener, 2004). We look forward to continued research on the correlates
and consequences of happiness. The causal efficacy of happiness has focused our research group
on one practical matter: interventions that build happiness.
Can Positive Psychology Make People Lastingly Happier?
From the Buddha through the human potential movement of the 1960s through the
pioneering work of Michael Fordyce (1977, 1983) through the self-improvement industry of the
1990s, at least one hundred "interventions" claiming to increase happiness lastingly have been
proposed. We have collected these and have distilled about forty of them into replicable and
manualizable form. Which of these really work, and which are at best placebos?
There exists a royal road for answering questions like these with respect to medication or
psychotherapy--the random-assignment placebo-controlled (RCT) design—and the very same
method can be used to validate what, if anything, builds the positive side of life. We first began
by teaching these exercises to students in undergraduate and graduate courses and then to a wide
variety of mental health professionals in a telephone course. We saw so many powerful "case
studies" (in which the testimonial "life-changing" kept appearing spontaneously) that we were
inspired to try them out in RCTs and determine if they worked when subjected to rigorous
testing.
We also considered the possibility that there would be no exercises that would make
people lastingly happier. Research into the hedonic treadmill, adaptation, and the heritability of
positive affectivity all implies that people adapt rapidly to positive changes in their world and
return to their baseline level of happiness (Brickman & Campbell, 1971; Kahneman, 1999;
Lykken & Tellegen, 1996). But because of the power of the case history anecdotes we
encountered, we decided to persist and to put the interventions to the random-assignment placebo
controlled test.
Positive Psychology 6
We now detail the efficacy of five exercises that we have so far put to this test. First, we
address two methodological issues: (a) how we measured happiness and depression; and (b) how
we delivered the intervention and collected outcome data via the Internet.
Measuring happiness and depression. Measuring depression was straightforward. We
used the CES-D symptom survey (Radloff, 1977). After surveying existing measurements of
happiness, however, we could find no parallel "symptom survey” of all the three forms of
happiness (positive emotion, engagement, and meaning). There exist useful measures of general
happiness (e.g., Fordyce, 1977; Lyubomirsky & Lepper, 1999), but these do not allow
researchers to make finer distinctions in levels of happiness, especially at the upper end of the
scale; scores are skewed and thereby impose a low ceiling. Nor do they include all of the
"symptoms" of the pleasant life, the engaged life, and the meaningful life.
In order to capture the week-by-week upward changes in happiness that we thought
might occur following our happiness interventions, we created a new measure, the Steen
Happiness Index (SHI). We used as our explicit model the Beck Depression Inventory (BDI;
Beck, Ward, Mendelson, Mock, & Erbaugh, 1961). Just as the BDI is sensitive to changes in
depressive symptoms, we created the SHI to be sensitive to changes, particularly upward
changes, in happiness levels. The SHI contains 20 items and requires participants to read a series
of statements and pick the one from each group that describes them at the present time. The
items on the SHI reflect the three kinds of happy lives (the pleasant life, the engaged life, and the
meaningful life): experiencing and savoring pleasures, losing the self in engaging activities, and
participating in meaningful activities. Response choices range from a negative (= 1) to an
extreme positive (= 5). For example:
A. Most of the time I am bored. (1)
B. Most of the time I am neither bored nor interested in what I am doing. (2)
C. Most of the time I am interested in what I am doing. (1)
D. Most of the time I am quite interested in what I am doing. (2)
E. Most of the time I am fascinated by what I am doing. (3)
Pilot work with several hundred adult respondents showed that scores on this measure
converge substantially with other measures of happiness (r = .79 with the Lyubomirsky &
Lepper’s [1999] General Happiness Scale and r = .74 with Fordyce’s [1977] Happiness Scale as
would be expected, but that they were, as we hoped, more bell-shaped. Furthermore, change in
SHI scores across a one-week period were sensitive to the self-reported occurrence of positive
and negative events, even when prior SHI scores were controlled.
Internet-based interventions. We used the Internet to recruit participants, to deliver the
intervention, and to collect our data (Prochaska, DiClemente, Velicer, & Rossi, 1993). At this
stage in our intervention research, this convenience sample served our purposes well, because on
average we have 300 new registrants every day to our website (www.authentichappiness.org)
which contains many of the positive questionnaires free. But we also believe this sample may be
at least equal to, and perhaps superior to, college sophomores or clinic volunteers in its scientific
justification. One small advantage of collecting data via the Internet is that it obviates data entry
by the researcher (and associated human error). One larger advantage is substantial cost-
effectiveness in large sample studies. After paying for website development and maintenance,
there are virtually no additional costs to data collection for adequately-powered studies, and we
have offered the use of our website to interested researchers.
Much more scientifically important, and controversial, is the possibility of biased
sampling. Gosling, Vazire, Srivastava, and John (2004) compared survey data collected via the
Internet to survey data collected via traditional methods. They concluded that: (a) Internet data
are just as diverse as data collected via traditional methods; (b) participants who voluntarily
Positive Psychology 7
participate in web-based studies are no more psychologically disturbed than traditional
participants; and (c) participants in Internet studies are no less likely to take the study seriously
or to provide accurate information than participants in traditional samples. We believe our
sample is biased but in a relevant direction. It is tilted toward those who want to become happier,
exactly the ultimate target of our interventions. We would not want to generalize our findings to
people who do not want to become happier or to people who have to be coerced into taking
psychological tests. Based on these considerations, we chose to use the Internet.
Procedure. For our first large RCT, we designed five happiness exercises and one placebo
control exercise. Each exercise was delivered via the Internet and could be completed within one
week. One of these exercises focused on building gratitude, two focused on increasing awareness
of what is most positive about oneself, and two focused on identifying strengths of character. In a
randomized, placebo-controlled study, we compared the effects of these exercises with those of
what we thought would be a plausible placebo control: journaling for one week about early
memories. We followed our participants for six months, periodically measuring symptoms of
both depression and happiness.
We recruited a convenience sample from among visitors to the website created for
Seligman's (2002) book Authentic Happiness by creating a link called "Happiness Exercises."
The study was described on the site as an opportunity to help test new exercises designed to
increase happiness. Over the course of approximately one month, we recruited 577 adult
participants, 42% male and 58% female. Almost 2/3 of the participants (64%) were between the
ages of 35 and 54. Of the participants surveyed, 39% had a degree from a four-year college and
27% had some graduate school education. Notably, only 4% of the participants did not have
education or vocational training after high school, another limit on the generalizability of our
findings. Consistent with their reported level of education, approximately 3/4 of the participants
classified their income level as "average" or above. The sample was largely white (77%)..
Visitors were told that the exercise they were to receive was not guaranteed to make them
happier and that they might receive an inert (placebo) exercise. We did not offer any initial
financial incentives for doing the exercises. In order to insure good follow-up, we did tell
participants, however, that upon completion of follow-up tests at one week, one month, three
months, and 6 months after completing the exercise, they would be entered into a lottery. The
lottery prizes included one $500 award and three $100 awards.
After participants agreed to the terms presented, they answered a series of basic
demographic questions and completed two questionnaires: the SHI and CES-D as already
described. Then participants received a randomly assigned exercise. Participants were
encouraged to print out or write down the instructions for their exercise and keep them accessible
during the week to come. They were instructed to return to the website to complete follow-up
questionnaires after completing their assigned exercise.
Participants received reminder e-mails. The first reminder, sent early in the week,
repeated the instructions for their assigned exercise. They were also given contact information
and encouraged to contact the researchers with any questions or concerns. The second reminder
e-mail, sent later in the week, reminded participants to return to the website for the follow-up
questionnaires: "Thank you again for participating in our study. Please remember to return to
[url] by [relevant date] to give us feedback about your exercise and complete follow-up
questionnaires."
When participants returned to the website after their exercise, they completed the same
measures of happiness and depression administered at pre-test. In addition, participants answered
a "manipulation check" question to assess whether they had in fact completed the exercise as
instructed during the relevant time period (scored yes or no).
Positive Psychology 8
Of the 577 participants who completed baseline questionnaires, 411 (71%) completed all
five follow-up assessments. Participants who dropped out of the study did not differ from those
who remained on their baseline happiness or depression scores, nor was there differential
dropout from the six exercises. We include in our analyses only those participants who
completed all follow-up questionnaires1.
Detailed descriptions of the exercises are available upon request , but here are overviews
of each:
• Placebo control exercise: early memories - Participants were asked to write about
their early memories every night for one week.
• Gratitude visit - Participants were given one week to write and then deliver a letter of
gratitude in person to someone who had been especially kind to them but had never
been properly thanked.
• Three good things in life - Participants were asked to write down three things that
went well each day and their causes every night for one week. In addition they were
asked to provide a causal explanation for each good thing.
• You at your best - Participants were asked to write about a time when they were at
their best and then to reflect on the personal strengths displayed in the story. They
were told to review their story once every day for a week and to reflect on the
strengths they had identified.
• Using signature strengths in a new way - were asked to take our inventory of
character strengths online at www.authenichappiness.org and receive individualized
feedback about their top five ("signature") strengths (Peterson, Park, & Seligman,
2005). They were then asked to use one of these top strengths in a new and different
way every day for one week.
• Identifying signature strengths - This exercise was a truncated version of the one just
described without the instruction to use signature strengths in new ways. Participants
were asked to take the survey, to note their five highest strengths, and to use them
more often during the next week.
Results of the interventions. Two of the exercises—using signature strengths in a new
way and three good things—increased happiness and decreased depressive symptoms for six
months. Another exercise, the gratitude visit, caused large positive changes for one month. The
two other exercises and the placebo control created positive but transient effects on happiness
and depressive symptoms. Not surprisingly, the degree to which participants actively continued
their assigned exercise on their own and beyond the prescribed one-week period mediated the
long term benefits.
Here are more details. Using ANOVAs followed by planned contrasts, we compared the
scores of participants across the following time points: pre-test, immediate post-test (after doing
their exercise for one week), 1 week after the post-test, 1 month after the post-test, 3 months after
the post-test, and 6 months after the post-test. Figures 1 and 2 show the happiness and depression
scores of participants by assigned exercise. Sample sizes for each condition are shown in these
figures, as well as effect sizes associated with statistically significant (p < .05) contrasts for the
intervention group between baseline scores and those at the different follow-ups2.
An overall ANOVA for happiness scores (six conditions X six time periods) showed
significant effects for time (F = 26.38, p < .001) and for the interaction of condition by time (F =
12.38, p < .001). Similar effects were found for depression scores: significant effects for time (F
= 39.77, p < .001) and for the interaction of condition by time (F = 5.21, p < .001).
Participants in all conditions (including the placebo control condition) tended to be
Positive Psychology 9
happier and less depressed at the immediate post-test (after doing their exercise for one week)
(see Figures 1 and 2). One week later and at every testing period thereafter, however, participants
in the placebo control condition were no different than they had been at baseline.
As Figures 1 and 2 show, at the immediate post-test (after one week of doing the assigned
exercise), participants in the gratitude visit condition were happier and less depressed. In fact,
participants in the gratitude visit condition showed the largest positive changes in the whole
study. This boost in happiness and decrease in depressive symptoms was maintained at follow-up
assessment one week and one month. But by three months, participants in the gratitude visit
condition were no happier or less depressed than they had been at baseline.
Participants in the three good things exercise began to show beneficial effects at one
month following the post-test. At the one month follow-up, participants in this exercise were
happier and less depressed than they had been at baseline, and they stayed happier and less
depressed at the three month and six month follow-ups.
A similar long term improvement occurred for participants in the using signature
strengths in a new way condition. Immediate effects were less pronounced than for the three
good things condition, but at the one month follow-up and beyond, participants in this condition
were happier and less depressed than they had been at baseline. In contrast, participants in the
truncated identifying signature strengths condition showed an effect only at the immediate post-
test but not thereafter. Likewise, participants in the you at your best condition showed an effect
only at the immediate post-test.
What caused the long term benefits? Regardless of their exercise, participants were asked
explicitly to do their assigned exercise for only one week. When we contacted participants for
one-week, one month, three month, and six month follow-ups, we asked participants whether
they had indeed continued the exercise for more than one week on their own. We hypothesized
that continued practice of an intervention would mediate positive outcomes at follow-up. To test
this, we conducted ANOVAs with reported adherence to the exercise and continuing the exercise
as the independent variables, and the happiness score as the dependent variable. We did
analogous ANOVAs with depression (CES-D) score as the dependent variable.
The results were straight-forward. There was a significant effect for adherence to the
exercise on happiness scores at all time periods and a significant effect for adherence to the
exercise on depression scores at the one-month follow-up point. The interaction between
continuing the exercise and adherence to the exercise was significant for happiness scores,
indicating that participants who continued the exercises were the happiest. This interaction was
also significant when the CES-D was the dependent variable, indicating—again—that the long
term effects of the effective exercises (Figure 2) were most pronounced for those who continued
the exercises on their own.
The Future of Positive Interventions
We found specific interventions that make people lastingly happier, and we believe this
study holds implications—small and large—for the future of positive interventions and perhaps
for clinical interventions. We operationalized and compared five happiness interventions to a
placebo control in a sizable random assignment experiment, finding that two interventions—
writing about three good things that happened each day and why they happened, and using
signature strengths of character in a new way—made people happier (and less depressed) up to
six months later. One other intervention—the gratitude visit—produced large positive changes
but only for one month. Six months is far from “happily ever after,” but our results suggest that
lastingly increased happiness might be possible even outside fairy tales. Effect sizes were
"moderate" or larger and this is contradicts the widespread belief that the pursuit of happiness is
Positive Psychology 10
futile because of inevitable adaptation or an immutable hedonic set-point.
Participants in our study were asked to perform their assigned exercise for one week and
then return to the website periodically for follow-up assessments. Regardless of their assigned
exercise, participants—even those in the control group—were on average happier and less
depressed at immediate post-test. This pattern highlights the crucial importance of a longitudinal,
placebo-controlled design in research of this nature, particularly with participants who expect to
be made happier. As these studies continue and more exercises are explored, more and more
inert exercises will be found, and these inert exercises can serve as placebo controls even though
they were intended as active enhancers of well being. Parametric variation can also serve the
control group function, yielding “dose-response” curves for increasing intensity or duration of
the exercise.
Pioneers in this field (e.g., Fordyce, 1977, 1983) found that happiness levels could be
increased by “shotgun” interventions involving multiple exercises. Identifying specific
ingredients is an uncommon early move in the testing of interventions and our studies go beyond
such demonstrations, although further work is of course needed to identify the fine-detail of how
our interventions worked. We also recommend the random assignment placebo control. It may
be that the mere act of doing something assigned by a professional in the expectation of gain to
boost happiness is sufficient to lift one's spirits in the short-term (Frank, 1973). This may be
particularly true of our sample, composed as it is of people who want to become happier, who
are invested in the outcome, and who think www.authentichappiness.org is a plausible authority.
Baseline CES-D scores indicated that our participants were, on average, mildly depressed. Our
participants were probably motivated to try things to feel better, and most did—at least
temporarily. Hence the importance of placebo controls.
By one week following the intervention, participants in the placebo control group (the
early memories exercise) had returned to their baseline levels of happiness and depression
symptoms, and there they remained through the six-month follow-up. Those participants who
were asked to write a story about themselves at their best—you at your best—demonstrated the
same pattern as the placebo: an immediate boost in happiness after a week of doing the exercise
and an immediate reduction in depressive symptoms as well, with neither lasting beyond the
post-test. Therefore, we conclude that this exercise is not an effective intervention, at least not in
isolation.
We add "in isolation" because in our multi-exercise programs (which have not yet been
subjected to RCT), we use this exercise to introduce the signature strengths interventions, and it
is possible that telling an introductory story of one's highest strengths, followed by the effective
signature strength exercise, may amplify the benefits on happiness and depression. It seems
plausible—given that three of the interventions were effective when delivered alone—to suppose
that a package of positive interventions, perhaps including ones that were ineffective in isolation,
might well exceed the beneficial effects of any single exercise. Such packages, likely containing
some moves that are truly inert, some moves that are inert in isolation but effective in a package,
and some moves that are always active, is what any therapy consists in. We have designed and
are testing such packages.
Further, these single exercises were delivered with "no human hands," electronically on a
website. Discussions of therapeutic effects often emphasize the power of the relationship with
the therapist; only when that is in place do specific interventions work. Finding beneficial effects
with no human therapeutic alliance suggests the operation of powerful specific ingredients in the
exercises. We believe that in the hands of a skilled clinician or coach, even more beneficial
effects might occur. Our ongoing studies of packages of exercises delivered with human hands
find large effect sizes for relieving depression and increasing happiness, in contrast to the mostly
Positive Psychology 11
moderate effect sizes reported here.
We asked participants to do their assigned exercise for only one week. We did not
suggest that they should keep it up thereafter. In retrospect, we believe that one week may not be
enough time for participants in the using signature strengths in a new way condition and the
three good things condition to develop sufficient skills and experience. Yet participants in both
these conditions proceeded to benefit from these exercises up to six months later. We found that
the participants who continued to benefit from the exercises were those people who
spontaneously did them beyond the required one-week period, without our instruction to do so.
We believe that these two interventions are skills which improve with practice and are “fun, and
so are self-maintaining. Unlike many therapeutic outcomes, such as weight loss from dieting,
these exercises are “self-reinforcing.” The majority of participants in these conditions answered
"yes" to a question about whether they were continuing the exercise on their own.
As we continue to develop and test exercises, we will pay particular attention to the ease
with which the exercise can be integrated into one's daily schedule and to the processes of self-
maintenance. It may not be practical for individuals to schedule a formal gratitude visit on a
regular basis, but most people can make time every day to express their appreciation for
someone--elaborately and sincerely. In any package of positive interventions, it may be optimal
to intersperse exercises that make an immediate impact (e.g., the gratitude visit) with those
exercises that are easily integrated into the daily routine.
An important question left unanswered by the current study is whether "more is better"
when it comes to happiness interventions. Given that the using signature strengths in a new way
exercise, the three good things exercise, and the gratitude visit exercise were all effective, does it
make sense to assign them all to a person who wishes to be happier? And if so, is there an
optimal sequence? Is there a personality type for whom some exercises take and others do not?
We are currently testing both the number of exercises parametrically and in different sequences
in an attempt to bolster our effects on happiness and depression.
Measurement of positive states needs more research. Many happiness researchers
subscribe to the notion that happiness is necessarily subjective and is essentially whatever the
individual defines it to be (e.g., Lyubomirsky, Sheldon, & Schkade, in press). If happiness is in
the eye of the beholder, then self-report measures are the only appropriate measures. We do not
think that this approach is solid enough: Even though we may be the best judge of how happy we
are at the moment, we may not be accurate historians with respect to when and in what types of
situations we were happy in the past. One challenge for researchers is to develop better behavior-
based, domain-specific assessment tools. We suspect that productivity at work and physical
health follow the same patterns as subjective happiness, and we will welcome the day when
productivity and health measures join subjective measures.
Although our study is the most ambitious random assignment placebo controlled test of
happiness interventions we know, our interventions are documented only on a convenience
sample. This population was largely well-educated, White, and financially comfortable.
Furthermore, they were mildly depressed and motivated to become happier. Future research on
the efficacy of these exercises for individuals who are either much happier or much more
depressed than our current population and who come from other backgrounds may uncover
limits on the generality of positive interventions. We are currently asking this question
collaborating with disability counselors whose primary task is to help individuals with
disabilities to achieve high quality employment and a high quality of life.
Nor can we resist the speculation that happiness exercises may prove therapeutic in
depressive disorder. Importantly these interventions also reduced depressive symptoms lastingly,
and in other studies we are finding that this effect is massive. Typically in the therapeutic
Positive Psychology 12
endeavor, we tackle disorders head-on: we teach anxious people to relax, depressed people to
argue against depressing thoughts, people with conflict to gain insight into the sources, and
people with obsessive-compulsive disorders to find out that disasters do not ensue if they do not
perform their rituals. In fact, an unspoken premise of all “talk” therapy is to talk about your
troubles and by confronting them to overcome them. We see positive interventions as a
supplement to therapy focused on troubles, another arrow in the quiver of the therapist.
Psychotherapy as defined now is where you go to talk about your troubles and your weaknesses;
perhaps in the future it will also be where you go to build your strengths. Perhaps on the tenth
anniversary of the millennial issue of the American Psychologist, we will be able to review such
developments.
At least since the time of Aristotle, scholars, philosophers, and religious leaders have
pondered the question, "How can we become lastingly happier?" Yet until recently, the only
guiding question of clinical psychology and psychiatry has been, "How can we reduce
suffering?” We believe that psychology and psychiatry have found some answers to the suffering
question and that this is a fine beginning. But even if answered fully, the mission of psychology
should not end there. Few people are wholly content just with being less depressed and less
anxious and less angry. We suggest that the future mission of our profession include not only
reducing suffering but also increasing the total amount of happiness on the planet.
Positive Psychology 13
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Positive Psychology 15
Author Note
This research was supported by the Annenberg/Sunnylands Trust Foundation, by Atlantic
Philanthropies, by the John Marks Templeton Foundation, and by NIMH grant, MH63430.
Address correspondence to Martin E. P. Seligman, Positive Psychology Center, University of
Pennsylvania, 3701 Market Street, Philadelphia, Pa, 19104; seligman@psych.upenn.edu or to
Christopher Peterson, Department of Psychology, University of Michigan, 525 East University,
Ann Arbor, MI 48109-1109; chrispet@umich.edu.
Footnotes
1. Older people were happier (r = .18, p < .001) and less depressed (r = -.17, p < .001).
Gender and ethnicity were not associated with happiness or depression scores at baseline or at
any of the follow-up assessments. In our analyses, we initially controlled for age, but the results
were unaffected, so we present only the unadjusted means.
2. A closer look with ANOVAs at the individual interventions in comparison to the
placebo comparison condition detailed these effects. With respect to happiness, there were main
effects of time (gratitude visit: F = 39.13, p < .001; three good things: F = 8.76, p < .001; you at
your best: F = 26.77, p < .001; using signature strengths in a new way: F = 8.56, p < .001;
identifying signature strengths: F = 24.94, p < .001), for the interaction of condition by time for
the gratitude visit (F = 6.88, p < .001), for three good things (F = 16.47, p < .001), and for using
signature strengths in a new way (F = 17.91, p < .001) but not for you at your best (F = 1.75, ns)
or identifying signature strengths (F = .35, ns). With respect to depressive symptoms, there were
main effects of time (gratitude visit: F = 20.91, p < .001; three good things: F = 14.43, p < .001;
you at your best: F = 10.37, p < .001; using signature strengths in a new way: F = 13.35, p <
.001; identifying signature strengths: F = 6.59, p < .001), for the interaction of condition by time
for the gratitude visit (F = 4.62, p < .001), for three good things (F = 5.15, p < .001), for you at
your best ( F = 2.83, p < .02), and for using signature strengths in a new way (F = 4.56, p < .001)
but not for identifying signature strengths (F = .20, ns).
Positive Psychology 16
Table 1
Classification of Character Strengths (Peterson & Seligman, 2004)
1. wisdom and knowledge – cognitive strengths that entail the acquisition and use of knowledge.
• creativity: thinking of novel and productive ways to do things
• curiosity: taking an interest in all of ongoing experience
• open-mindedness: thinking things through and examining them from all sides
• love of learning: mastering new skills, topics, and bodies of knowledge
• perspective: being able to provide wise counsel to others
2. courage – emotional strengths that involve the exercise of will to accomplish goals in the face
of opposition, external or internal
• authenticity: speaking the truth and presenting oneself in a genuine way
• bravery: not shrinking from threat, challenge, difficulty, or pain
• persistence: finishing what one starts
• zest: approaching life with excitement and energy
3. humanity – interpersonal strengths that involve “tending and befriending” others
• kindness: doing favors and good deeds for others
• love: valuing close relations with others
• social intelligence: being aware of the motives and feelings of self and others
4. justice – civic strengths that underlie healthy community life
• fairness: treating all people the same according to notions of fairness and justice
• leadership: organizing group activities and seeing that they happen
• teamwork: working well as member of a group or team
5. temperance – strengths that protect against excess
• forgiveness: forgiving those who have done wrong
• modesty: letting one’s accomplishments speak for themselves
• prudence: being careful about one’s choices; not saying or doing things that might
later be regretted
• self-regulation: regulating what one feels and does
6. transcendence – strengths that forge connections to the larger universe and provide meaning
• appreciation of beauty and excellence: noticing and appreciating beauty, excellence,
and/or skilled performance in all domains of life
• gratitude: being aware of and thankful for the good things that happen
• hope: expecting the best and working to achieve it
• humor: liking to laugh and tease; bringing smiles to other people
• religiousness: having coherent beliefs about the higher purpose and meaning of life
Positive Psychology 17
Figure Captions
Figure 1. Steen Happiness Index (SHI) Scores. Figures are effect sizes corresponding to a
statistically significant (p < .05) difference between the intervention group at that point in time
and baseline. If no effect size is shown, the intervention group and the comparison group did not
differ.
Figure 2. Center for Epidemiological Studies-Depression (CES-D) Scores. Figures are
effect sizes corresponding to a statistically significant (p < .05) difference between the
intervention group at that point in time and baseline. If no effect size is shown, the intervention
group and the comparison group did not differ.
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