Rewards can be used effectively with repeated exposure to increase liking of vegetables in 4-6-year-old children

Abstract

Objective: To examine whether parents offering a sticker reward to their child to taste a vegetable the child does not currently consume is associated with improvements in children's liking and consumption of the vegetable.

Design: A randomized controlled trial evaluated the effectiveness of exposure only (EO) and exposure plus reward (E + R), relative to a control group, on children's liking and consumption of a target vegetable. Assessments were conducted at baseline and 2 weeks from baseline (post-intervention). Follow-up assessments were conducted at 4 weeks and 3 months from baseline.

Setting: The study took place in Adelaide, South Australia. Participants were self-selected in response to local media advertisements seeking to recruit parents finding it difficult to get their children to eat vegetables.

Subjects: Participants were 185 children (110 boys, seventy-five girls) aged 4-6 years and their primary caregiver/parent (172 mothers, thirteen fathers).

Results: The E + R group was able to achieve more days of taste exposure. Both EO and E + R increased liking at post-intervention compared with control and no further change occurred over the follow-up period. All groups increased their intake of the target vegetable at post-intervention. Target vegetable consumption continued to increase significantly over the follow-up period for E + R and control but not for EO.

Conclusions: The findings provide support for the effectiveness of using a sticker reward with a repeated exposure strategy. In particular, such rewards can facilitate the actual tastings necessary to change liking.

Fig. 1

Diagram showing the flow of participants through each stage of the randomized controlled trial

Fig. 2

Number of days of taste exposure (tastes), refusals to taste (refusals) and offers of the vegetable by the parent (offers), for the EO (exposure only, n 58; ) and the E+R (exposure plus reward, n 57; ) groups, in a randomized controlled trial conducted among children aged 4–6 years and their primary caregiver/parent, Adelaide, South Australia. Values are means with their standard deviations represented by vertical bars. Mean values were significantly different between groups: *P < 0·05

Fig. 3

Target vegetable liking ratings for the target vegetable at baseline ( ) and post-intervention ( ), and magnitude of change in rating from baseline to post-intervention ( ), for the control (baseline, n 64; post-intervention, n 61), EO (exposure only; baseline, n 35; post-intervention, n 34) and E+R (exposure plus reward; baseline, n 45; post-intervention, n 43) groups, in a randomized controlled trial conducted among children aged 4–6 years and their primary caregiver/parent, Adelaide, South Australia. Hedonics ratings represent ‘yummy’ above the ‘0’ point and ‘yucky’ below it. Values are means with their standard errors represented by vertical bars. Change between baseline and post-intervention was significant: *P < 0·05

Fig. 4

Target vegetable liking ratings for the target vegetable at post-intervention ( ), 4-week follow-up ( ) and 3-month follow-up ( ), for the control (post-intervention, n 61; 4 weeks, n 55; 3 months, n 57), EO (exposure only; post-intervention, n 34; 4 weeks, n 34; 3 months, n 35) and E+R (exposure plus reward; post-intervention, n 43; 4 weeks, n 40; 3 months, n 41) groups, in a randomized controlled trial conducted among children aged 4–6 years and their primary caregiver/parent, Adelaide, South Australia. Hedonics ratings represent ‘yummy’ above the ‘0’ point and ‘yucky’ below it. Values are means with their standard errors represented by vertical bars

Fig. 5

Target vegetable consumption on the previous day (g) at baseline ( ) and post-intervention ( ), and magnitude of change in consumption from baseline to post-intervention ( ), for the control (baseline, n 64; post-intervention, n 61), EO (exposure only; baseline, n 35; post-intervention, n 34) and E+R (exposure plus reward; baseline, n 45; post-intervention, n 43) groups, in a randomized controlled trial conducted among children aged 4–6 years and their primary caregiver/parent, Adelaide, South Australia. Values are means with their standard errors represented by vertical bars. Change between baseline and post-intervention was significant: *P < 0·05

Fig. 6

Target vegetable consumption on the previous day (g) at post-intervention ( ), 4-week follow-up ( ) and 3-month follow-up ( ), for the control (post-intervention, n 61; 4 weeks, n 55; 3 months, n 57), EO (exposure only; post-intervention, n 34; 4 weeks, n 34; 3 months, n 35) and E+R (exposure plus reward; post-intervention, n 43; 4 weeks, n 40; 3 months, n 41) groups, in a randomized controlled trial conducted among children aged 4–6 years and their primary caregiver/parent, Adelaide, South Australia. Values are means with their standard errors represented by vertical bars. Mean values were significantly different between time periods: *P < 0·05

Fig. 7

Frequency of vegetable consumption on the previous day at baseline ( ), 4-week follow-up ( ) and 3-month follow-up ( ), for the control (baseline, n 63, 4 weeks, n 56; 3 months, n 57), EO (exposure only; baseline, n 34, 4 weeks, n 32; 3 months, n 34) and E+R (exposure plus reward; baseline, n 44, 4 weeks, n 40; 3 months, n 41) groups, in a randomized controlled trial conducted among children aged 4–6 years and their primary caregiver/parent, Adelaide, South Australia. Values are means with their standard errors represented by vertical bars. Mean values were significantly different between time periods: *P < 0·05