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

46 M. Craeynest et al. / Eating Behaviors 9 (2008) 41–51
3.3. Mean evolution in implicit and self-reported attitudes during treatment
3.3.1. Implicit attitudes
Physical activity. A 3 (time: T1 vs. T2 vs. T3) ×3 (word category: sedentary activities vs. moderate intense PA vs.
high intense PA) ×2 (extrinsic response valence: positive vs. negative) Repeated Measures ANOVA only revealed a
main effect of time on the reaction times, F(2, 17)=10.22, pb.01, indicating that the participants reacted faster on the
persecuting test moments (respectively T1: M=858 ms, SD=47 ms; T2: M=733 ms, SD=34 ms; T3: M=674 ms,
SD=29 ms). No effects were found for word category, all Fsb1.82, and extrinsic response valence, all Fsb2.56. This
indicated that the participants remained neutral towards sedentary activities, moderate and intense PA. The same
3×3×2 ANOVA performed on the percentages of errors, showed no significant effects, all Fsb1.35.
Food. Using a 3 (time: T1 vs. T2 vs. T3)×2 (word category: unhealthy vs. healthy food) ×2 (extrinsic response
valence: positive vs. negative) Repeated Measures ANOVA, the results only revealed a main effect for time, F(2, 17)=
416.88, pb.001. This indicated that the participants react faster on the persecuting test moments (respectively T1:
M=868 ms, SD=59 ms; T2: M=724 ms, SD=38 ms; T3: M=694 ms, SD=23 ms). No effects were found for word
category and extrinsic response valence, all Fsb3.23. The same 4×2×2 ANOVA was conducted on the percentages of
errors, however no significant effects were found, all Fsb2.10. Implicit food and physical activity associations are
presented in Table 1.
3.3.2. Self-reported attitudes
Physical activity. A 3 (time: T1 vs. T2 vs. T3)×3 (word category: sedentary activities vs. moderate intense vs. high
intense PA) Repeated Measures ANOVA showed a main effect of time, F(2, 17)=5.93, pb.05, indicating that the
participants became more positive on the successive measure moments (T1: M=1.47, SD=0.14; T2: M=1.81,
SD=0.14; T3: M=2.01, SD=0.11). Also the main effect of word category was significant, F(2, 17)=8.16, pb.01.
Post hoc paired t-tests revealed that in general, moderate intense PA (M=2.09, SD=0.50) was rated more positive than
sedentary activities (M=1.68, SD=0.40), t(18) =3.59, pb.01, and than high intense PA (M=1.52, SD=0.77), t(18) =
2.78, p b.05. Sedentary activities and high intense PA were rated equally, tb1. The interaction effect of time and word
category was not significant, Fb1.
Food. A 3 (time: T1 vs. T2 vs. T3) ×2 (word category: unhealthy vs. healthy food) ANOVAwith Repeated Measures
showed a main effect of word category, F(1, 17)=6.46, pb.05. A post hoc paired t-test revealed that, in general, the
participants were more positive towards healthy (M=1.97, SD=0.69) than towards unhealthy food (M=0.91,
SD=1.51), t(18)=2.38, pb.05. The main effect of time and the interaction effect of time and word category were not
significant, both Fsb1. Table 2 describes the mean self-reported attitudes for the persecuting test moments.
3.4. Prediction of ABMI change during treatment by attitudinal change during treatment
To investigate whether attitudinal changes could explain the variance in ABMI change, we conducted standard
multiple regression analyses. Because of the small sample size, the predictive power of the several attitudinal change
variables on ABMI change was examined separately for implicit and self-reported attitudes and for food and physical
activity, resulting in four different models. In each model, baseline ABMI, age and sex (entered as a dummy variable:
girl=0; boy=1) were entered as covariates. ABMI and attitudinal change during treatment were calculated by
respectively subtracting the ABMI and attitudinal scores at T1 from T2.
3.4.1. Implicit attitudes towards physical activity
In a first model, ABMI change during treatment was the dependent variable, and the change in attitude towards
sedentary activity (RT), towards moderate intense PA (RT), towards high intense PA (RT), towards sedentary activity
(PE), towards moderate intense PA (PE), towards high intense PA (PE), baseline ABMI, age and sex were entered as
independent variables. The model accounted for 73% of the variance, F(9, 18)=6.51, pb.01. Attitudinal change
towards high intense PA (RT) was a significant predictor, adjusted for age, sex and baseline ABMI, β=.51; t(18) =2.91,
pb.05. Remarkably, this indicated that a decrease in overweight was related to a more negative attitude towards high
intense PA at the end of the treatment. Further, also baseline ABMI, β = −.57; t(18)=4.03, p b.01, and sex, β =.64;
t(18)=4.12, p b.01, were significant predictors. The first indicated that decrease in overweight was related to a
higher baseline ABMI, and the latter indicated that girls had a higher probability to decrease in overweight than