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

50 M. Craeynest et al. / Eating Behaviors 9 (2008) 41–51
given the fact that these effects were not found on both performance levels (reaction times and percentage of errors)
and that earlier studies did not show any evidence for implicit attitudes towards physical activity (e.g., Craeynest
et al., 2005; butseeBarton et al., 2004), the implicit attitude effects should be interpreted with caution. In contrast,
decrease in overweight seemed to be strongly related to ‘fixed’ variables such as sex, age and baseline ABMI (see
also Braet, 2006).
There are several aspects that may offer a possible explanation for the only limited and tentative implicit attitude effects we
found. First, it is obvious that the small sample size, due to the huge dropout, may have reduced the power of the analyses.
Second, the treatment took place in a very controlled setting with strict diet and exercise guidelines. Given the
accumulating evidence that the environment is an important predictor for food choice and physical activity (Booth
et al., 2001), it may be that the decrease in overweight during treatment was rather due to ‘external’ environmental
characteristics, than to ‘internalized’ psychosocial determinants such as implicit attitudes.
Third, it has been demonstrated that implicit measures may not be considered as stable constructs that are
immune for contextual influences (Blair, 2002). Therefore, it may be that the results were attenuated by the different
contexts in which the youngsters were assessed (at the medical paediatric centre, at the university, and for a minority
at home).
Fourth, as mentioned in the Introduction, there is no doubt that using indirect measures may have several advantages
over self-reports (Greenwald et al., 2002). Nevertheless, each of the paradigms has its own limitations that should be
considered. With respect to the EAST, at this moment little is known about its validity and reliability. Huijding and de
Jong (2005) found that a pictorial version of the EAST had good predictive validity for avoidance behaviour in
individuals with spider phobia. However, Teige, Schnabel, Banse, and Asendorpf (2004) found that the EAST
investigating implicit self-concept of personality had low internal consistency. Undoubtedly, more research is needed
about the psychometric characteristics of the EAST, not only in general, but also within specific domains such as in the
assessment of food and physical activity cognitions in children and adolescents. In addition, it should be investigated to
what extent the performance on indirect measures in a longitudinal study design is related to learning effects. Steffens
(2004) found that faking becomes easier after having some experience with an IAT, and probably the same is true for
the EAST.
Finally, there are some limitations that should be considered. First, the results of the treatment, both on decrease in
overweight and on attitudinal change, would have been stronger if they could be compared with those of an untreated
group of obese youngsters. Second, food and exercise attitudes are not direct determinants of weight, but they are
mediated by food intake and exercise behaviour. Therefore, future research should include objective behavioural
measures. Moreover, correlations between these behavioural and the implicit measures can provide then an idea of the
validity of the implicit measures (see Teachman & Woody, 2003).
In sum, this study showed that a decrease in overweight in obese youngsters after a six month inpatient treatment
was not significantly related to self-reported attitudes. In contrast, a decrease in overweight seemed to be related to
some changes in implicit attitudes towards food and physical activity, but these findings should be interpreted with
caution. More research is needed to the psychometric qualities of implicit measures within this field, and to what extent
implicit food and exercise attitudes are related to actual food intake and exercise behaviour.
Acknowledgements
This research was supported by grant B/03814/01 from the Ghent University. We are very grateful to the MPC
Zeepreventorium and the children for their cooperation to this study. In addition, we wish to thank Jan De Houwer for
his ideas on conceptualizing the experiment. Furthermore, many thanks go to all colleagues and students who assisted
in data collection, especially Els Persijn, Leen Van Vlierberghe, Katrien Verhoeven and Mieke De Roo.
Appendix A
Target stimuli of the EAST
Target stimuli food:
Unhealthy food words: crisps, coke, French fries
Healthy food words: water, apple, tomato