The role of implicit attitudes towards food and ... - ResearchGate

42 M. Craeynest et al. / Eating Behaviors 9 (2008) 41–51
research is necessary to investigate whether the underlying dynamics of the food and physical activity behaviour are
affected by the treatment, and to what extent their change is related to weight loss and weight regain.
Several characteristics have been found to be important predictors of weight loss in obese youngsters following
treatment, under which baseline degree of overweight and the child's age (Braet, 2006). Further, an amount of theories
have dealt with possible explaining psychological determinants, such as the learning history of the child and a
heightened responsiveness to food cues (for a review, see Braet, 2005). From a healthy psychology perspective,
attitudes towards food and exercise have been put forward as crucial factors in the development and maintenance of
obesity (e.g., De Bourdeaudhuij et al., 2005; Dennison & Shepherd, 1995).
In most studies, attitudes are asked directly, for instance using self-reports. Recently, however, it has been argued
that their indirect assessment, by which cognitions are inferred from behaviour performance other than self-report,
should have a better explanatory and predictive value because of two reasons (Greenwald et al., 2002). First, indirect
measures should be more resistant for demand characteristics that often affect self-reports (see Schwarz, 1999). Second,
indirect measures are supposed to catch cognitive automatic associations that guide spontaneous behaviour, and that
can not easily be tapped by self-reports. The outcome of the indirect assessment of these associations is often called
implicit cognitions. Implicit attitudes then are the measure of automatic associations between an attitude object and a
certain valence (Greenwald et al., 2002).
In the last decades, several indirect response time based paradigms have been constructed to assess implicit attitudes
(for a review, see Fazio & Olson, 2003), amongst which the affective priming task (Fazio, Sanbonmatsu, Powell, &
Kardes, 1986), the Implicit Association Task (IAT; Greenwald, McGhee, & Schwartz, 1998) and the Extrinsic
Affective Simon Task (EAST; De Houwer, 2003). The core principle of these tasks is that implicit attitudes are inferred
from the reaction time (and percentage of errors) performance on a computer sorting task. More specifically, it is
assumed that response latencies will be shorter (and less errors will be made) when participants have to use the same
response bottom to sort stimuli that carry the same valence (congruent stimuli; e.g., names of insects and negative
nouns vs. names of flowers and positive nouns), than when the same response bottom has to be pressed for stimuli with
an opposite valence (incongruent stimuli; e.g., names of insects and positive nouns vs. names of flowers and negative
nouns). Implicit attitudes are calculated then by comparing the performance on the congruent stimuli with the
performance on the incongruent stimuli.
Indirect measures have been applied in several domains of clinical and health psychology (for a review, see Fazio &
Olson, 2003). As described elsewhere (Craeynest et al., 2005), we used the EAST in a cross-sectional study
investigating implicit food and exercise attitudes in children and adolescents with obesity at the beginning of an
intensive treatment. Our results revealed a borderline significant effect, indicating that youngsters with obesity
implicitly preferred both unhealthy and healthy food, whereas normal-weight controls evaluated them as neutral. No
effects were found for physical activity.
Longitudinal research investigating whether implicit food and physical activity cognitions in youth obesity change over
a treatment period, and to what extent they are related to treatment success (i.e., weight loss or weight gain), is scarce. We
only know of the study by Barton, Walker, Lambert, Gately, and Hill (2004) in which a sentence-completion questionnaire
was used to investigate whether automatic exercise and food cognitions change over the course of a residential weight loss
camp for adolescents with obesity. They found a reduction in negative and an increase in positive thoughts about exercise,
but not in those about eating. Further, cognitive change was largely accounted for by the reduction in weight.
This manuscript describes a longitudinal study in which implicit and self-reported food and exercise attitudes are
assessed in youngsters with obesity during a six month inpatient treatment and at a one year follow up. Self-reported
attitudes are assessed with a questionnaire; implicit attitudes are assessed with an EAST. Three main questions are
addressed: First, do implicit and self-reported food and exercise attitudes change during an inpatient treatment for obesity?
Second, to what extent does a change in these attitudes explain the variance in weight change during treatment? And third,
to what extent does a change in these attitudes explain the variance in weight loss or regain at follow up?
2. Methods
2.1. Participants
Participants were thirty-eight obese children and adolescents at the beginning of their hospitalization in 2002–2003
in a medical-paediatric centre (MPC) that is specialized in the treatment of youth obesity. Fourteen of them dropped out