The team recruited 111 British children between the ages of four and six years old and played each of them one of three videos.
In two of the videos, the children were shown unfamiliar adults eating raw broccoli with either a positive or a neutral facial expression. The third video, used as a control, was not food related.
The researchers then assessed the children’s willingness to try raw broccoli. This was measured using a seven-point scale from turning away from it to both swallowing and accepting it. Their intake of the vegetable was measured by the number of grams of raw broccoli consumed, and the number of tastes of raw broccoli was examined.
The findings could help children become more accepting of less popular vegetables like raw broccoli and generally facilitate healthier eating in children. The research mainly focused on young children who had never tried broccoli before.
The team found that children who were exposed to video clips of adults enjoying eating broccoli had more tastes of, and ate, on average, more than twice as much of the food in comparison with the kids in the control group—specifically, 11 g (0.4 oz) rather than 5 g (0.2 oz).
Katie Edwards, PhD researcher at Aston University, said: “One explanation for the beneficial effect of positive facial expressions whilst eating could be that conveying food enjoyment gives the observer information about the safety and palatability of food.”
“Raw broccoli was novel for most participants. Thus, children may have eaten more broccoli after watching adults enjoy eating it, because they believed it was enjoyable to eat.”
The researchers were surprised to find, however, that seeing adults enjoying raw broccoli did not impact the children’s initial willingness to try the vegetable.
The results showed that after watching adults enjoying eating raw broccoli, children ate more than double the amount of raw broccoli than children who had seen a non-food-related video. This suggests that smiling while eating green vegetables can encourage children to taste and eat more of that vegetable.
Katie added: “Further work is needed to determine whether a single exposure [to adults enjoying broccoli] is sufficient and whether these effects are sustained over time.”
The full findings of the study were published in the journal Appetite.