Blackwell Publishing LtdOxford, UKOBRObesity Reviews1467-7881© 2007 Queen’s Printer and Controller of HMSO; published with permission; Journal compilation © 2007 The
International Association for the Study of Obesity? 20078123125Review ArticleSocial psychological factors in tackling obesity G. R. Maio et al.
obesity reviews
Social psychological factors in tackling obesity
G. R. Maio, G. G. Haddock and H. L. Jarman
School of Psychology, Cardiff University,
Keywords: Attitudes, ambivalence, obesity, implicit.
Cardiff, UK
Accepted 28 November 2006
Address for correspondence: Professor GR
Maio, School of Psychology, Cardiff University,
Cardiff CF10 3AT, UK.
E-mail: maio@Cardiff.ac.uk
OnlineOpen: This article is available free online at www.blackwell-synergy.com
Background: the role of ambivalence in
healthy behaviour
In the fight to reduce rising levels of obesity, a persistent
obstacle is the psychological conflict between things people
want to eat – for instance, fatty or sweet foods – and good
health. People have very mixed feelings and beliefs about
healthy lifestyle options. They experience positive sensations from eating foods that provide excessive calorie and
salt content, yet finding the time to exercise (which in itself
they may find unpleasant) is difficult. People know that rich
foods are bad for them but, on the other hand, they also
know that moderate exercise is good for them (1). No one
escapes the psychological conflict, or ‘ambivalence’ that
ensues. Yet, public information campaigns insist on simply
reminding people to avoid certain foods and to exercise,
rather than helping to resolve this deep-seated ambivalence.
Ambivalence is an important issue because prior experimental evidence from the field of social psychology reveals
it to be an important obstacle to healthy behaviour. Healthrelated ambivalence makes it psychologically difficult to
resist the temptations of unhealthy choices.
Several studies illustrate the effort required to overcome
unhealthy temptations (2). In one study, young teenagers
were given the opportunity to eat a large quantity of crisps,
which they consumed with glee. The experimenter then
presented them with a jug of Quench, a ‘new’ bright-red
drink, along with a written description of its positive and
negative attributes. The thirsty participants were told that
they could have some of the drink, but it would be better
to wait until later because supplies were short. The participants then sat alone with the drink for 10 min. During this
obesity reviews (2007) 8 (Suppl. 1), 123–125
time, the experimenter unobtrusively videotaped them and
gave them an additional questionnaire to assess the ways
in which they had coped with their temptation to drink the
beverage.
Analyses revealed that the participants tried a range of
strategies to avoid drinking the beverage. Some participants
moved the tasty-looking juice away from them. Others
tried to focus attention on other materials that were available in the laboratory (e.g. magazines) or tried to highlight
the negative (not positive) aspects of the drink in the questionnaire that the experimenter had given to them. In addition, participants even created negative attributes of the
drink (e.g. that it was ‘too sweet’) that were never even
mentioned in the initial, brief description. These behaviours betray a high amount of psychological effort aimed
at combating temptation. More important, this effort
occurred more strongly when the experimenter emphasized
that the participants were free to choose whether or not to
consume the beverage. Freedom of choice makes it more
difficult to resist temptation. Other research and theory
indicate that stress (3,4) and habit formation also impede
the ability to resist temptation (5). Yet, choice, stress and
habit are all inescapable or difficult to reduce.
Methods to reduce health-related ambivalence
So how can we help people cope with this ambivalence?
Unfortunately, there is good reason to doubt the efficacy of
interventions that simply provide new persuasive information. The problem is that people who are high in ambivalence towards an issue carefully scrutinise any information
that can help resolve their conflict (6,7). As a result, ambiv-
This paper was commissioned by the Foresight programme of the Office of Science and Innovation, Department of Trade and Industry
© 2007 Queen’s Printer and Controller of HMSO; published with permission
Journal compilation © 2007 The International Association for the Study of Obesity. obesity reviews 8 (Suppl. 1), 123–125
123
124
Social psychological factors in tackling obesity
G. R. Maio et al.
alent individuals are more likely to pick out flaws in the
messages when the messages are overly simplistic (e.g. ‘just
say no’) and form more negative attitudes and behaviours
towards the healthy options after detecting the flaws.
Indeed, a series of studies sponsored by the Economic and
Social Research Council have demonstrated this type of
backfire when anti-racism messages are presented to
people who are highly ambivalent towards ethnic-minority
groups (8).
A more basic problem with a persuasive information
approach is that it may fail to positively affect nonconscious evaluations of health-related behaviours. Indeed,
the research on anti-racism messages revealed backfire
effects of persuasive messages on implicit measures of attitude, which assess evaluations that people are unable or
unwilling to retrieve from memory (9–11). Implicit measures do not ask people to directly report their attitudes
but, instead, assess their attitudes without their immediate
awareness or control (e.g. using subliminal presentation of
stimuli). Importantly, responses on implicit measures are
often discordant with self-reported (explicit) attitudes. For
example, a person may explicitly report that she dislikes
chocolate cake because of its perceived health impact, yet
she exhibits a strong desire to eat the cake on an implicit
measure (compare this with the work of Roefs et al. (12)).
This difference is important because it is the scores on
the implicit measures that tend to best predict actual spontaneous behaviour (13,14). Thus, it is vital that interventions manage to influence the associations tapped by the
implicit measures and not just the attitudes obtained by
self-report measures. It is likely that this non-conscious
attitude change requires repeated and creative interventions to change attitudes – even a single powerful message
might not be enough to elicit long-term non-conscious
change (15).
Potential clues to addressing this problem are revealed
by important evidence that ambivalence has unique neurological properties. Using functional magnetic resonance
imaging brain imaging techniques, Cunningham et al.
found that regions of the prefrontal cortex (PFC), specifically the ventrolateral PFC, are more active when people
make evaluations of objects that elicit ambivalence, over
and above the activity associated with emotional valence
and intensity, in regions such as the amygdala (16). This
pattern indicates that ambivalence has unique neuropsychological substrates, which may help us understand the
effects of ambivalence on behaviour.
In fact, such evidence may help to solve an interesting
behavioural puzzle about ambivalence. Specifically, ambivalence tends to elicit polarized responses to the objects of
the ambivalence (i.e. extremely positive or extremely negative) (1), despite eliciting enhanced scrutiny of relevant
persuasive messages as described above (7). In other words,
ambivalent people tend to respond in extreme ways that
obesity reviews
are consistent with salient situational factors, despite resisting direct social influence. One potential resolution is that
the polarization and resistance effects occur over different
timescales. The studies showing response polarization
have used very obvious and immediate cues (e.g. mood;
good behaviour) that may be salient within a ‘teachable
moment’, when a person is still processing their conflicting
evaluations. In contrast, the persuasive messages require
longer periods of attention and deliberation, and they
may fail, partly because they are not comprehended early
enough during the person’s thoughts about an object, and
before the person has begun to resolve their ambivalence
in a particular direction.
Neurological scanning can be used to better track the
time course of ambivalence (e.g. using event-related potential or magnetoencephalography) and to test whether situational cues have a different impact during the activation
of brain regions that are associated with ambivalence than
after this activation has subsided. Such evidence may reveal
ways in which interventions can be shaped to use, rather
than challenge, ambivalence. For example, it may be possible to develop signage or messages that give instant
pictorial cues to healthy behaviour immediately after eliciting feelings of ambivalence about a behaviour. These
approaches may be more successful than those that use
drawn-out print messages for ambivalent topics.
Conclusion
Ambivalence and difficulties in trying to resolve it are
important in the health context. It is important to develop
interventions that are capable of affecting the non–
conscious associations that plausibly direct many
unhealthy behaviours, and the tools are present to test this
possibility. There are also powerful tools (e.g. brain imaging techniques) for looking more directly at the neurological structure and consequences of health-related
ambivalence. The use of such tools can coincide with
attempts to explore the ways in which social psychological
approaches to healthy behaviour change can be adapted to
suit public health interventions. We believe that this agenda
should be an important aim for future research.
Conflict of Interest Statement
No conflict of interest was declared.
References
1. Bell DW, Esses VM. Ambivalence and response amplification:
a motivational perspective. Pers Soc Psychol Bull 2002; 28: 1143–
1152.
2. Lima MV. Self persuasion strategies to resist temptation.
Unpublished doctoral dissertation, Cardiff University, UK,
2005.
This paper was commissioned by the Foresight programme of the Office of Science and Innovation, Department of Trade and Industry
© 2007 Queen’s Printer and Controller of HMSO; published with permission
Journal compilation © 2007 The International Association for the Study of Obesity. obesity reviews 8 (Suppl. 1), 123–125
obesity reviews
Social psychological factors in tackling obesity
3. Kruglanski AW, Webster DM Motivated closing of the mind:
‘seizing’ and ‘freezing’. Psychol Rev 1996; 103: 263–283.
4. Muraven M, Baumeister RF. Self-regulation and depletion of
limited resources: does self-control resemble a muscle? Psychol
Bull 2000; 126: 247–259.
5. Wood W, Quinn JM, Kashy DA. Habits in everyday life:
thought, emotion, and action. J Pers Soc Psychol 2002; 83: 1281–
1297.
6. Jonas K, Diehl M, Bromer P. Effects of attitudinal ambivalence
on information processing and attitude-intention consistency. J
Exp Soc Psychol 1997; 33: 190–210.
7. Maio GR, Bell DW, Esses VM. Ambivalence and persuasion:
the processing of messages about immigrant groups. J Exp Soc
Psychol 1996; 32: 513–536.
8. Maio GR, Haddock GG, Watt SE, Hewstone M. Implicit
measures and applied contexts: an illustrative examination of
anti-racism advertising. In: Petty RE, Fazio RH, Brinol P (eds).
Attitudes: Insights from the New Wave of Implicit Measures (in
press).
9. Greenwald AG, McGhee DE, Schwartz JKL Measuring individual differences in implicit cognition: the implicit association
test. J Pers Soc Psychol 1998; 74: 1464–1480.
G. R. Maio et al.
125
10. Schuette RA, Fazio RH. Attitude accessibility and motivation
as determinants of biased processing: a test of the MODE model.
Pers Soc Psychol Bull 1995; 21: 704–710.
11. Wittenbrink B, Judd C, Park B. Evidence for racial prejudice
at the implicit level and its relationship with questionnaire measures. J Pers Soc Psychol 1997; 72: 262–274.
12. Roefs A, Stapert D, Isabella LAS, Wolters G, Wojciechowski
F, Jansen A. Early Associations with food in anorexia nervosa
patients and obese people assessed in the affective priming paradigm. Eat Behav 2005; 6: 151–163.
13. Dovidio JF, Kawakami K, Gaertner SL. Implicit and explicit
prejudice and interracial interaction. J Pers Soc Psychol 2002; 82:
62–68.
14. Dovidio JF, Kawakami K, Johnson C, Johnson B, Howard A.
On the nature of prejudice: automatic and controlled processes. J
Exp Soc Psychol 1997; 33: 510–540.
15. Wilson TD, Lindsey S, Schooler TY. A model of dual attitudes. Psychol Rev 2000; 107: 101–126.
16. Cunningham WA, Johnson MK, Gatenby JC, Gore JC, Banaji
MR. Neural components of social evaluation. J Pers Soc Psychol
2003; 85: 639–649.
This paper was commissioned by the Foresight programme of the Office of Science and Innovation, Department of Trade and Industry
© 2007 Queen’s Printer and Controller of HMSO; published with permission
Journal compilation © 2007 The International Association for the Study of Obesity. obesity reviews 8 (Suppl. 1), 123–125