40 Food Choice
Food as the reward
Other research has explored the impact of using food as a reward. For these
studies, gaining access to the food is contingent upon another behavior, as
in “If you are well behaved you can have a cookie.” Birch, Zimmerman,
and Hind (1980) presented children with foods as a reward, as a snack,
or in a nonsocial situation (the control). The results showed that food
acceptance increased if the foods were presented as a reward, but that the
more neutral conditions had no effect. This suggests that using food as a
reward increases the preference for that food.
The relationship between food and rewards, however, appears to be more
complicated than this. In one study, children were offered their preferred
fruit juice as a means to be allowed to play in an attractive play area
(Birch et al., 1982). The results showed that using the juice as a means to
get the reward reduced the preference for the juice. Similarly, Lepper et al.
(1982) told children stories about a child eating imaginary foods called
“hupe” and “hule,” in which the child in the story could only eat one if
they had finished the other. The results showed that the food which was
used as the reward became the most preferred one, and this has been
supported by similar studies (Birch, Marlin, and Rotter, 1984; Newman and
Taylor, 1992). These examples are analogous to saying “If you eat your
vegetables, you can eat your dessert.” Although parents use this approach
to encourage their children to eat vegetables, the evidence indicates that
this may be increasing their children’s preference for pudding even further,
as pairing two foods results in the “reward” food being seen as more
positive than the “access” food. As Birch (1999) concluded, “Although these
practices can induce children to eat more vegetables in the short run,
evidence from our research suggests that in the long run parental control
attempts may have negative effects on the quality of children’s diets by
reducing their preferences for those foods” (p. 51).
Not all researchers, however, agree with this conclusion. Dowey (1996)
reviewed the literature examining food and rewards and argued that the
conflicting evidence may relate to methodological differences between
studies, and that studies designed to change food preference should be con-
ducted in real-life situations, should measure outcomes over time and not
just at one time point, should involve clear instructions to the children,
and should measure actual food intake, not just the child’s stated preference.
The recent intervention study described above incorporated these meth-
odological considerations into its design (Lowe, Dowey, and Horne, 1998)
and concluded that food preferences could be improved by offering rewards