The Role of Self-identity in the Theory of
Planned Behavior: A Meta-Analysis
Jostein Rise1
Paschal Sheeran
Norwegian Institute for
Alcohol and Drug Research
Oslo, Norway
University of Sheffield
Sheffield, UK
Silje Hukkelberg
Department of Mental Health, Norwegian Institute
of Public Health Oslo, Norway
The present study used meta-analysis to evaluate the role of self-identity in the
theory of planned behavior (TPB). Altogether, 40 independent tests (N = 11607)
could be included in the review. A large, sample-weighted average correlation
between self-identity and behavioral intention was observed (r+ = .47). Multiple
regression analyses showed that self-identity explained an increment of 6% of the
variance in intention after controlling for the TPB components, and explained an
increment of 9% of the variance when past behavior and the TPB components
were controlled. The influence of self-identity on behavior was largely mediated by
the strength of behavioral intentions. Theoretical implications of the findings are
discussed.
jasp_611
1085..1105
If a person sees himself or herself as concerned about the environment,
does this mean that the person is likely to intend to recycle? And does this
“environmental identity” directly influence recycling intentions, or does
holding the identity mean that the person is more likely to see recycling as
advantageous (i.e., hold a positive recycling attitude), perceive social pressure
to recycle (i.e., believe there is a supportive subjective norm), or believe
that recycling is easy (i.e., see the behavior as under one’s personal control)?
The present research is concerned with these questions. In particular, we
meta-analyzed the findings of studies that have measured self-identity, attitude, subjective norm, perceived behavioral control, and intention to assess
the nature and strength of relations between self-identity and behavioral
intentions.
1
Correspondence concerning this article should be addressed to Jostein Rise, Norwegian
Institute for Alcohol and Drug Research, P.O. Box 565, Sentrum 0105, Oslo, Norway. E-mail:
[email protected]
1085
Journal of Applied Social Psychology, 2010, 40, 5, pp. 1085–1105.
© 2010 Copyright the Authors
Journal compilation © 2010 Wiley Periodicals, Inc.
1086 RISE ET AL.
Theories of Reasoned Action and Planned Behavior
The relation between attitudes and behavior has been an area of major
concern in social psychology ever since the seminal review by Wicker (1969),
indicating that the ability of attitudes to predict behavior is actually quite
poor (cf. Eagly & Chaiken, 1993). Perhaps the most important attempts to
remedy this problem have been the introduction of the theory of reasoned
action (Fishbein & Ajzen, 1975) and its successor, the theory of planned
behavior (TPB; Ajzen, 1988).
The theory of reasoned action (TRA) proposed that the concept of behavioral intention (e.g., “I intend to buy organic produce”) mediates the relationship between attitude and behavior, and put forward the concept of
subjective norm as a second predictor of intention. Whereas attitude refers to
the person’s overall evaluation of performing the behavior (e.g., “For me,
buying organic produce would be good/bad”), subjective norm refers to perceived social pressure from important others to perform, or not to perform,
the behavior (e.g., “Most people who are important to me think that I should
buy organic produce”).
The theory of planned behavior (TPB) added the concept of perceived
behavioral control to the TRA as a third predictor of intention. Perceived
behavioral control (PBC) refers to the perceived ease or difficulty of performing a behavior (e.g., “For me, buying organic produce would be easy/
difficult”). Thus, according to the TPB, the more positive the person’s
attitude, the stronger the subjective norms and the greater the perceived
control over the behavior, the more likely it is that the person will intend to
perform the behavior. Correspondingly, the stronger the intention to
perform the behavior, the more likely it is that the person will perform the
behavior, assuming, of course, that the person possesses “actual control”
over the performance (see Ajzen & Madden, 1986; Sheeran, Trafimow, &
Armitage, 2003).
Several meta-analyses have shown that behavioral intention is predictable
from the three components of the TPB (e.g., Armitage & Conner, 2001a;
Godin & Kok, 1996; Sheeran & Taylor, 1999). However, the level of prediction is far from perfect; the variance explained in intention ranges from just
28% to 40%, on average. This consideration has led several researchers to
question the sufficiency assumption of the TPB; that is, the assumption that
the theory adequately captures all theoretical determinants of intention. In
fact, Ajzen (1991) relaxed this assumption when he developed the TPB,
stating that the TPB is, in principle, open to inclusion of additional predictors
so long as they increase the explained variance in behavioral intentions.
Accordingly, several researchers have proposed additional predictors that
might be used to augment the model’s predictive validity (for reviews, see
SELF-IDENTITY META-ANALYSIS
1087
Abraham, Sheeran, & Johnson, 1998; Conner & Armitage, 1998). The aim of
the present research is to provide the first comprehensive quantitative assessment of one important additional variable; namely, self-identity.
Role of Self-Identity in the Theories of Reasoned Action and
Planned Behavior
The case for including self-identity as an additional predictor in the TPB
derives from theorists who have argued that identity processes should be
taken into account in the prediction of specific behaviors, and from empirical
evidence that self-identity predicts behavioral intentions after attitudes and
norms have been taken into account (e.g., Biddle, Bank, & Slavings, 1987;
Charng, Piliavin, & Callero, 1988; Sparks & Shepherd, 1992). Self-identity
refers to salient and enduring aspects of one’s self-perception (e.g., “I think of
myself as a ‘green consumer’”; cf. Sparks, 2000). According to identity theory
(e.g., Thoits & Virshup, 1997), people apply socially meaningful categories to
describe themselves when answering the question “Who am I?” in terms of,
for example, sociodemographic characteristics (e.g., gender), social roles
(e.g., mother, father), social types (e.g., smoker, exerciser, healthy eater,
blood donor), and even personality traits (e.g., honest, optimist).
Thus, self-identities (or “me” identifications) are the perspective one takes
toward oneself when taking the role of specific or generalized others, implying that one incorporates the meanings and expectations associated with a
relevant categorization into the self, thus forming a set of identity standards
that guide identity-relevant behaviors (Stets & Burke, 2000). However, from
a reasoned action perspective, self-identity constitutes an external variable
that is assumed to exert its effect through the components of the model
and should, accordingly, have no independent value in the prediction of
behavioral intentions.
Sparks (2000) reviewed two theoretical grounds for assuming that components of the TPB mediate the self-identity/intention relation. The first line
of argument assumes that self-identity exhibits conceptual overlap with attitudes because self-identity is likely to represent a class of behavioral outcomes that are on a par with utilitarian and affective outcomes expected to
flow from behavioral performances (cf. Eagly & Chaiken, 1993). According
to this idea, the concept of attitude should capture whatever influence selfidentity has on intention. When empirical studies do not support this prediction, it has been argued that this is because self-identity concerns may
not have been especially salient when people responded to the evaluative
scales typically used to tap attitude toward behaviors (Eagly & Chaiken,
1993).
1088 RISE ET AL.
However, identity theorists (e.g., Biddle et al., 1985) have argued that
attitudes, norms, and self-identity have different motivational roots. Individuals conform to attitudes for instrumental reasons and to norms for fear
of being rejected by significant others (i.e., external sanctions), whereas one
acts in accordance with one’s self-identity for self-verification reasons. That
is, people are motivated to retain and affirm the sense of self and identity
(cf. Stets & Burke, 2000): People act to be consistent in their identity standard. By this account, when the social categorization including the identity is
activated, the person behaves so as to maintain consistency with the meanings held in the identity standards. Accordingly, self-identity will tend to
predict intentions above the components of the TPB.
The second reason why self-identity may not predict intention after TPB
components have been taken into account relates to the possibility that
self-identity may simply reflect past performance of a behavior. The argument is that people understand what kind of persons they are by making
inferences based on their past behavior (i.e., through a self-perception
process; Bem, 1972). This idea suggests that self-identity should have no
direct effect on behavioral intentions once the effect of past behavior has
been controlled. Relatively few empirical studies have addressed this issue,
and mixed findings have been obtained.
Some studies have observed that self-identity retains a unique effect on
behavioral intentions after TPB components and past behavior have been
taken into account (Conner, Warren, Close, & Sparks, 1999; Hildonen, 2001;
Thompson & Rise, 2002); some studies have not shown an independent
effect of self-identity on behavioral intentions (e.g., Fekadu & Kraft, 2001);
whereas in other studies it has not been possible to separate the effect of
self-identity on intention from that of past behavior because other predictors
were included in the same step (Conner & Flesch, 2001; Conner & McMillan,
1999; Terry, Hogg, & White, 1999). In sum, it remains unclear whether the
association between self-identity and behavioral intention merely reflects
experience with the focal behavior.
A further conceptual difficulty associated with evaluating the strength of
the self-identity/intention relation relates to a general problem with what can
be termed the additional-variables paradigm in TPB research. In this paradigm, researchers identify a variable that is not specified in the TPB, measure
that variable in a TPB study of a particular behavior, and then assume that
if the variable captures unique variance in intention (after TPB predictors are
controlled), then their variable constitutes an additional predictor in the
TPB. As O’Keefe (2002) pointed out, this practice undermines the principle
of parsimony and is likely to lead to the development of a plethora of
behavioral intention models whose validity and generalizability are indeterminate (also see Trafimow, 2004).
SELF-IDENTITY META-ANALYSIS
1089
To guard against this problem, O’Keefe (2002) proposed two criteria that
should be used to evaluate additional predictors in the TPB. First, a given
conceptual candidate should provide a large additional contribution to the
prediction of intention (after controlling for components of the TPB), which
reaches well beyond statistical significance. Second, the proposed concept
needs to demonstrate its utility in predicting behavioral intentions across a
wide range of behavioral domains.
However, it is clear that primary research studies are rarely in a position
to satisfy O’Keefe’s (2002) criteria. What is needed is a meta-analytic strategy
that accumulates effect sizes across studies in a manner that permits general
conclusions. Only one meta-analysis of the self-identity/intention relation has
been conducted to date (Conner & Armitage, 1998), and this review deserves
updating, for two reasons. First, the meta-analysis examined only six studies;
and second, past behavior was not taken into account in the analysis. The
conclusion we draw is that a new meta-analysis of the self-identity/intention
relation—one that includes recent research and that permits statistical
control of both TPB components and past behavior—is overdue.
The Present Study
Based on the foregoing discussion, the aim of the present study is to
provide a meta-analytic integration of research on self-identity and the TPB.
In particular, the review aims to (a) quantify the strength of the relationship
between self-identity and behavioral intentions; (b) estimate the increment
in the variance in intentions that is attributable to self-identity after TPB
variables have been taken into account; (c) estimate the increment in variance
attributable to self-identity after both TPB variables and past behavior have
been taken into account; and (d) assess whether intention mediates the selfidentity/behavior relationship.
Method
Selection of Studies
Several procedures were used to collect the samples of studies: (a) social
scientific databases (e.g., BIDS, Conference Papers Index, PsychLit) were
searched; (b) reference lists of identified papers were evaluated for inclusion;
and (c) authors of published papers were contacted for potential unpublished
studies and studies that were in press. In order to be included in the review,
a bivariate statistical association between self-identity and behavioral
1090
RISE ET AL.
intention had to be retrievable from the studies. We also coded correlations
for future behavior, past behavior, and TPB variables whenever available. In
total, 40 independent tests of the self-identity/intention relation were identified from 33 papers. Table 1 presents the characteristics and effect sizes of the
studies that were included in the review.
Meta-Analytic Strategy
To provide an estimate of the effect size, the weighted average of the
sample correlations (r+) was used. This coefficient describes the direction and
strength of the relationship between two variables ranging from -1.00 to
+1.00. We assumed that studies in the meta-analysis were sampled from
populations with mean effect sizes that vary (i.e., random-effects model).
Therefore, we used the Hunter–Schmidt method (Hunter & Schmidt, 1990;
Hunter, Schmidt, & Jackson, 1982; for a discussion, see Field, 2001, 2005).
Homogeneity analyses were conducted using the chi-square statistic
(Hunter et al., 1982) to determine whether variation among the correlations
was greater than by chance. The formula for degrees of freedom for this test
is k - 1, where k is the number of independent correlations. If chi square is
nonsignificant, then the correlations are homogeneous and the average
weighted effect size (r+) can be said to represent the population effect size.
Computation of weighted average effect size and homogeneity statistics were
conducted using Schwarzer’s (1988) Meta computer program.
Multiple Regression Analyses
All of the studies included in the review reported intercorrelations
between self-identity and TPB variables. Correlations among self-identity,
past behavior, and all TPB predictors were available in 11 cases. We used
computations of the sample-weighted average correlations among selfidentity, TPB variables, and past behavior as the input matrix for multiple
regression in order to determine the increment in variance attributable to
self-identity after controlling for relevant predictors.
Results
Sample-Weighted Average Correlations
The guidelines provided by Cohen (1992) are useful for interpreting
the magnitude of the sample-weighted average correlations (r+). Cohen
Give money to charity
Exercise
Casual sex
Cannabis use
Alcohol consumption
Alcohol consumption
Students
Austin & Sheeran (2001)
Campbell & Sheeran (2001)
Conner & Flesch (2001)
Conner & McMillan (1999)
Conner, Warren, Close, & Sparks
(1999, Study 1)
Conner, Warren, Close, & Sparks
(1999, Study 2)
Young adults,
general population
Students
Students
Students
Students
Students
Åstrøm & Rise (2001)
Eat a low-fat diet
Eat a low-fat diet
Eat a low-fat diet
Donate blood
Donate blood
Intentions to work for
National Health Services
Eat healthy food
Behavior
Students
Hospital workers
General population
Prospective students
Students
General population
Sample
Armitage & Conner (1999a)
Armitage & Conner (1999b)
Armitage & Conner (1999c)
Armitage & Conner (2001b, Study 1)
Armitage & Conner (2001b, Study 2)
Arnold et al. (2006)
Authors
Studies of the Relation Between Self-Identity and Behavioral Intention
Table 1
175
251
181
384
249
176
735
221
413
110
134
172
978
N
.57
.17
.56
.29
.81
.48
.65
.57
.56
.54
.69
.44
.19
r
SELF-IDENTITY META-ANALYSIS
1091
Moan & Rise (2006)
Moan, Rise, & Andersen (2004)
Ouellette & Wood (1998)
Rapaport & Orbell (2000)
Conner, Warren, Close, & Sparks
(1999, Study 3)
de Pelsmacker & Janssens (2007)
Evans & Norman (2003)
Fekadu & Kraft (2001)
Giles, McClenahan, Cairns, &
Mallet (2004)
Hagger & Chatzisarantis (2006,
Study 1)
Hagger & Chatzisarantis (2006,
Study 2)
Hildonen (2001)
Jackson, Smith, & Conner (2003)
Mannetti, Pierro, & Livi (2004)
Authors
Table 1 Continued
Various mundane
behaviors
Dieting behavior
Buy ecological products
Physical activity
Recycling
University students
Students
University employees
Students and young
workers
Adolescents
Parents
Students
University students
Reduce smoking
Smoking
Various behaviors
Provision of emotional
support and practical
assistance
Speeding behavior
Road crossing
Use contraceptives
Donate blood
General population
Adolescents
Female adolescents
University students
University students
Alcohol consumption
Behavior
Students
Sample
145
159
71
195
206
85
230
250
241
334
1833
354
100
159
N
.31a
.25
.69
.23
.69
.50
.41
.80
.83
.23
.42
.31
.59
.65
r
1092 RISE ET AL.
Community residents
Females
University students
Terry, Hogg, & White (1999)
Theodorakis (1994)
Theodorakis, Bagiatis, & Goudas
(1995)
Thompson & Rise (2002)
Eat organic vegetables
Attitudes toward
genetically modified
foods
Household recycling
Participate in a physical
fitness program
Teach individuals with
disabilities
Exercise and recycle
drinking cartons
Eat a low-fat diet
Eat a low-fat diet
Quit smoking
Quit smoking
Buy sustainable-produced
foods
Purchase British beef
Eat a low-fat diet
232
99
143
395
261
99
239
216
182
242
204
204
550
.61
.71
.56
.31
.37
.74
.46
.70
.44
.64
.17
.34
.30
Because self-identity was measured with respect to smoker identity, whereas intention was measured with respect to smoking
reduction, this correlation has been recoded.
a
Sparks & Shepherd (1992)
Spence & Townsend (2006)
Sparks & Guthrie (1998, Study 3)
College students
Students
UK sample, general
population
Danish sample,
general population
Finnish sample,
general population
General population
General population
Sheeran (1998)
Sparks & Guthrie (1998, Study 1)
Sparks & Guthrie (1998, Study 2)
Spanish students
Norwegian students
General population
Rise & Ommundsen (2010, Study 1)
Rise & Ommundsen (2010, Study 2)
Robinson & Smith (2002)
SELF-IDENTITY META-ANALYSIS
1093
1094 RISE ET AL.
Table 2
Meta-Analysis of Self-Identity and Theory of Planned Behavior Variables
Relationship
r+
95% confidence interval
c2
Intention/self-identity
Intention/attitude
Intention/subjective norm
Intention/PBC
Attitude/self-identity
Attitude/subjective norm
Attitude/PBC
Subjective norm/self-identity
Subjective norm/PBC
PBC/self-identity
.47
.50
.39
.35
.37
.36
.25
.29
.14
.25
.46–.49
.49–.51
.37–.40
.33–.36
.36–.39
.35–.38
.23–.27
.28–.31
.12–.16
.24–.27
761.83***
604.19***
203.06***
1280.11***
438.46***
258.46***
749.62***
263.69***
434.04***
1185.81***
Note. N = 11607. k = 40. N = sample size on which sample-weighted average correlation is based; k = number of correlations; r+ = sample-weighted average correlation;
c2 = chi-square test for homogeneity of sample correlations; PBC = perceived
behavioral control.
***p < .001.
proposed that a correlation of .10 is small, .30 is medium, and .50 is
strong.
Table 2 presents the average correlations obtained among self-identity
and TPB variables (k = 40). The sample-weighted average correlation
between self-identity and behavioral intentions was of medium magnitude
(r+ = .47), according to Cohen’s (1992) criteria (95% confidence interval =
.46–.49). The robustness of this correlation can be determined by estimating
the number of unpublished studies with null findings that would be required
to invalidate the conclusion that self-identity and intentions are significantly
associated at the 5% alpha level. The fail-safe N (Rosenthal, 1984) was 35485,
which greatly exceeds the recommended tolerance level of 5k + 10. Because it
is extremely unlikely that there are so many studies with null results that we
were unable to locate, the average correlation between self-identity and intention should be considered robust.
The reliability of measures of self-identity included in the meta-analysis
was generally high (mean a = .78). Nevertheless, we elected to account
for measurement error using the formulas described by Hunter et al. (1982).
The sample-weighted average correlation corrected for unreliability was .52.
SELF-IDENTITY META-ANALYSIS
1095
Thus, 1.3% of the variance was a result of unreliability, and 4.1% of the
variance was a result of sampling error.
The discriminant validity of self-identity, compared to the other components of the TPB, was also supported by the findings (Table 2). The highest
average correlation was between self-identity and attitude (r+ = .37). The
magnitude of this association indicates that there is only modest conceptual
overlap between the two concepts. Similarly, small to medium correlations
were obtained between self-identity and both subjective norm and PBC
(r+s = .29 and .25, respectively).
Self-Identity as an Additional Predictor of Intention in the TPB
A two-step hierarchical regression analysis was conducted to determine
whether self-identity enhances the prediction of behavioral intentions beyond
that engendered by the TPB on its own. The components of the TPB were
included in the first step, and self-identity was entered in the second step (see
Table 3). Attitude was the strongest determinant in the first step (beta = .36,
p < .001), although subjective norm and PBC were also significant predictors
of intention. These three predictors accounted for 35% of the variance in
intentions.
Table 3
Hierarchical Regression of Intention on Theory of Planned Behavior Variables
and Self-Identity
Variable
Step 1
Attitude
Subjective norm
Perceived behavioral control
Step 2
Self-identity
2
R
Model F
DR2
Fchange
Note. N = 11607. k = 40.
***p < .001.
Beta
.36***
.23***
.23***
.35
2075.09***
Beta
.29***
.18***
.18***
.28***
.41
651.50***
.06
2021.14***
1096 RISE ET AL.
Notwithstanding this level of prediction by TPB variables, the inclusion
of self-identity in the second step significantly enhanced the prediction of
behavioral intentions (DR2 = .06, p < .001). Together, the four predictors
accounted for 41% of the variance in intention. Attitudes and self-identity
exhibited the highest beta weights (betas = .29 and .28, respectively), as compared to .18 for both subjective norms and PBC.
Predictive Validity of Self-Identity Controlling for TPB Variables and
Past Behavior
In the next analysis, TPB variables were entered on the first step, past
behavior was entered on the second step, and self-identity was entered on the
third step of a hierarchical regression (k = 16; N = 3488). The TPB components accounted for 31% of the variance (see Table 4), and past behavior
explained an additional proportion of the variance (5%). In the final step,
self-identity was able to account for a highly reliable increment of 9% in
the variance explained in behavioral intentions. In this subgroup of studies,
Table 4
Hierarchical Regression of Intention on Theory of Planned Behavior Variables,
Self-Identity, and Past Behavior
Variable
Step 1
Attitude
Subjective norm
Perceived behavioral control
Step 2
Past behavior
Step 3
Self-identity
2
R
Model F
DR2
Fchange
Note. N = 3488. k = 16.
***p < .001.
Beta
.36***
.25***
.20***
.31
525.38***
Beta
Beta
.31***
.20***
.18***
.22***
.16***
.14***
.23***
.16***
.36
485.92***
.05
253.37***
.34***
.45
560.75***
.09
552.38***
SELF-IDENTITY META-ANALYSIS
1097
self-identity turned out to be the strongest determinant of intentions, along
with attitude (betas = .34 and .22, respectively), whereas the betas for TPB
predictors were clearly lower. These findings suggest that self-identity cannot
be construed as simply a reflection of past behavior, but captures a separate
and distinct psychological process in the formation of behavioral intentions.
Does Intention Mediate the Self-Identity/Behavior Relation?
There were 13 studies (N = 2141) that included a prospective measure of
behavior in which intercorrelations with self-identity, intention, and PBC
could be retrieved. Using the sample-weighted average correlations as the
input matrix, regression of behavior on intention and PBC showed significant
beta coefficients for both predictors (betas = .47 and .29, respectively;
ps < .001), and 36% of the variance in behavior was explained. The bivariate
association between self-identity and behavior was significant (beta = .43,
p < .001). Including self-identity on the second step of the regression equation engendered a significant increment in the variance accounted for
(Fchange = 82.93, DR2 = .02, p < .001). Self-identity, intention, and PBC each
had significant beta coefficients (betas = .20, .30, and .35, respectively;
ps < .001).
Although these findings appear to suggest that self-identity has a direct
influence on behavior, even after intention and PBC have been taken into
account, two considerations speak against this interpretation. First, correlations between PBC and both intention and self-identity were unusually small
in this subset of studies (r+s = .22 and .08, respectively), so findings are likely
to have been different if the values were similar to those obtained in the larger
sample of studies (see Table 2). Second, self-identity was significantly associated with behavior after intention and PBC were controlled in none of the
13 primary studies, which suggests that the significant association may simply
be an artifact of the large sample included in the meta-analysis. Finally, it is
worth noting that a Sobel’s test indicated that intention was a highly reliable
mediator of the self-identity/behavior relation (Z = 22.76, p < .001).
Discussion
The present study examined 40 tests of the predictive validity of selfidentity using meta-analytic procedures and, therefore, constitutes the most
comprehensive and systematic analysis of the self-identity/intention relation
to date. The key findings from the review can be summarized as follows:
Self-identity had a medium-sized average correlation with behavioral
1098
RISE ET AL.
intention, according to Cohen’s (1992) criteria. The association between
self-identity and intention was similar in magnitude to the attitude–intention
relationship (r+s = .48 and .50, respectively) and was larger than the average
subjective-norm/intention, and PBC–intention correlations (r+s = .39 and .35,
respectively). In addition, fail-safe N analyses indicate that the self-identity/
intention association was robust (i.e., resistant to future null results).
Multiple regression analyses show that self-identity enhanced the prediction of intention after components of the TPB—and components of the TPB
plus past behavior—were taken into account. Findings show that selfidentity captured 6% additional variance in intention above and beyond that
afforded by attitude, subjective norm, and PBC, whereas a 9% increase in
explained variance in intention was observed when past behavior was also
controlled. Finally, mediation analysis suggests that the influence of selfidentity on behavior was largely, and perhaps entirely, mediated by the
strength of behavioral intention.
Although the results of the meta-analysis seem to support the inclusion of
self-identity as an additional predictor in the TPB, O’Keefe’s (2002) criteria
must be considered before firm conclusions can be drawn. O’Keefe’s first
criterion is that any potential additional variable in the TPB should contribute a large additional contribution to the prediction of intention, and not
simply a statistically reliable increment. In our view, values of 6% and 9%
additional variance satisfy this criterion. Self-identity explains substantial
additional variance in intention beyond that engendered by TPB variables
and past behavior.
O’Keefe’s (2002) second criterion is that the efficacy of a candidate variable must be demonstrated across a wide range of behaviors. Canary and
Seibold’s (1984) comprehensive categorization of behaviors, examined in
attitude–behavior theories (also see Kim & Hunter, 1993), indicates that
research in the following categories were included in the review: health
behavior (e.g., Sparks & Guthrie, 1998), consumer behavior (e.g.,
Hildonen, 2001), contraceptive behavior (Fekadu & Kraft, 2001), academic
behavior (Theodorakis, Bagiatis, & Goudas, 1995), altruistic behavior (e.g.,
Rapaport & Orbell, 2000), and environmental behavior (e.g., Terry et al.,
1999).
The major categories in which data were not available for inclusion in the
meta-analysis concern the domains of group participation, voting, race relations, religiosity, and deviance. Although it would have been desirable to
include behaviors from these categories, we do not believe that their absence
seriously undermines the meta-analysis, not least because identity concerns
seem highly relevant for behaviors in the absent categories. Overall, it is fair
to suggest that self-identity exhibited good predictive validity across a wide
range of behaviors. Thus, the findings from the present review would seem to
SELF-IDENTITY META-ANALYSIS
1099
satisfy O’Keefe’s (2002) criteria and warrant the conclusion that self-identity
constitutes an important additional predictor in the TPB.
Theoretical implications of this conclusion also deserve attention. Attitude theorists (e.g., Eagly & Chaiken, 1993) have argued that self-identity
refers to a particular class of behavioral outcomes and, therefore, should
overlap with standard attitude measures that (according to both the TRA
and TPB) capture these outcomes. However, two findings in particular seem
to contradict this analysis. First, the variance shared by self-identity and
attitude was quite modest (R2 = .14); and second, self-identity had a significant association with intention, even after the association between attitude
and intention was statistically controlled. Both of these findings should have
been impossible if attitude and self-identity referred to the same concept.
Instead, our findings seem to be more consistent with Biddle et al.’s (1985)
perspective that self-identity has different motivational origins, compared to
attitude and subjective norm. According to this view, a key component of
people’s motivation to formulate behavioral intentions (and, subsequently,
to enact those intentions) is to reinforce, support, and confirm their sense of
self (see Stets & Burke, 2000). In this context, it is timely to reinforce the idea
that the role of self-identity should be interpreted in terms of socially defined
influences, distinct from normative influences (Åstrøm & Rise, 2001; also see
Hagger & Chatzisarantis, 2006). Thus, self-identities derive from socially
constructed categories or types of person, which are accepted by individuals
as descriptive of themselves (see Thoits & Virshup, 1997). In this capacity, the
role of self-identity in the TPB provides an account of the failure of subjective
norm (i.e., the social influence component of the TPB) as a predictor of
intentions, as compared with attitudes and PBC (see Ajzen, 1991).
The findings are also contrary to a self-perception theory perspective on
the nature of self-identity, for similar reasons. Although there was a reliable
association between past behavior and self-identity, the variance shared by
the two concepts was quite modest (R2 = .11), and self-identity predicted
intention, even after past behavior was controlled. Thus, although the acquisition of particular self-identities may be derived, at least in part, from
experience of particular behaviors, self-identity is clearly not simply reducible
to such experience.
Finally, it may be worthwhile to note that self-identity is distinct
from group identity, although both of them are social identities (Stets &
Burke, 2000; Thoits & Virshup, 1997). While self-identity constitutes
me-identification—that is, identification of the self as, say, a smoker—and
includes the meanings, expectations, and activities related to being a smoker,
group identity constitutes we-identification of the self with, say, other
smokers, which implies acting on behalf of the group of smokers (cf. Thoits &
Virshup, 1997). This distinction tends to be blurred in conceptualizations
1100 RISE ET AL.
(Hagger & Chatzisarantis, 2006) and measurement of self-identity
(Falomir & Invernizzi, 1999).
Thus, Falomir and Invernizzi (1999) found that a measure of smoker
identity predicted intention to quit smoking above the TPB components in a
sample of Spanish adolescents. A close inspection of the measure of smoker
identity in Falomir and Invernizzi’s study reveals that it was a mixture of
self-identity as a smoker (“To what extent do you feel as a smoker?”) and
identification with the group of smokers (“To what extent do you identify
with the group of smokers?”). Hence, this study was not included in the
present study. The basic idea is that smokers in many contexts view themselves in terms of what it means to be a smoker as a certain type of social
person (“I am a smoker”), but may in another context shift to a group
identity (“we smokers”) to unite in opposition to a common identity threat;
for example, when health authorities restrict smoking in public places
(e.g., restaurants). Evidence for this distinction was provided by Rise and
Ommundsen (2010), who found that the two concepts were only weakly
related and that they predicted intentions to quit smoking independently.
In conclusion, the present meta-analysis provides the strongest evidence
to date that the concept of self-identity is conceptually and empirically distinct from attitude, subjective norm, PBC, and past behavior. Across a wide
variety of behavioral domains, the self-identity/intention relation rivaled
the strength of the attitude–intention relation. Moreover, self-identity was
responsible for a substantial increment in variance explained in behavioral
intentions, even after the components of the TPB and past behavior had been
taken into account. In our view, these findings warrant the conclusion that
self-identity is a vital predictor of intentions and behavior and should be
incorporated into the dominant model of attitude–behavior relations; that is,
the theory of planned behavior.
This suggests that self-identity may be a distinctive target for persuasive
strategies, but, as noted by O’Keefe (2002) in his review of the literature, there
appears to be little systematic research on identity-based influence strategies.
Nevertheless, he proceeded to suggest two possible labeling strategies: to
make an existing identity more readily activated, and to provide people with
alternative identities. In this context, it may be important to reiterate the
implications of the theoretical underpinnings of the concept; namely, that
identity change is a long-term and reciprocal process. For example, behavior
adjusts to conform to the meanings of the identity standard; while at the same
time, the identity standard changes to adjust to the meaning of the behavior
(cf. Stets & Burke, 2003). These ideas imply that when health authorities
implement intervention programs directed at breaking unhealthy behavioral
patterns, they must consider that they are, in effect, trying to construct
new identities in the sense that the meanings, expectations, and activities
SELF-IDENTITY META-ANALYSIS
1101
associated with becoming a certain type of person or belonging to a novel
social category must be incorporated into the self so as to complete the
behavioral change process. To some extent, this may explain why it is so
difficult to break unhealthy behavioral patterns (e.g., quitting smoking).
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