Some kids just have a natural love for peas, beets or carrots — but not enough of them. This country has too many obstinate little people who don’t eat things that aren’t the colour white. America’s health statistics attest to that: As of 2012, almost one-third of kids ages 2-19 in the United States were considered overweight or obese.
So how do you get kids to eat better, beyond blending cauliflower in the mashed potatoes or hiding mushrooms in the sloppy joes? There’s a fierce debate, both among parents and psychologists, over whether parents and educators should bribe kids to eat healthily. Recent research suggests that, while there can be some downsides to the strategy, it can also really work.
In a study published in the journal Health Economics in January, researchers carried out a field experiment to try to motivate 8,000 children in different schools to eat healthier. They found that giving the students a small incentive for eating healthy — in this case, a 25 cent token the kids could spend at the school store, carnival or book fair — doubled the fraction of kids eating at least one serving of fruits or vegetables.
The researchers also found that the effects lingered after the experiment ended, though they did subside somewhat. Two months after the end of the experiment, kids who had been rewarded for their health behaviour for a period of five weeks were still eating 44 per cent more fruit and vegetables than they had before the experiment begun.
The authors argue that the study provides evidence that short-run incentives can help form lasting behaviours and that longer periods of “interventions” are more effective at changing behaviour than shorter ones.
There’s an obvious downside to these practices. Psychological studies have shown that, while external rewards like bribes are effective at getting people to adopt certain behaviours, they can undermine what’s called intrinsic motivation — a person’s internal drive to do a task, for example because it makes them feel more autonomous or competent.
In a 1999 analysis of 128 previous studies, researchers found that giving people rewards did significantly reduce their motivation to pursue the activity when they were not given a reward. In simpler terms that are probably obvious to any parent — bribing kids can spoil them.
Even when this is true, however, there’s often another force at work that may be even more important in changing people’s behaviours in the long-term: healthy life habits. Once people do something over and over again, it can become a subconscious, almost involuntary, inclination. And recent research suggests that those healthy habits have more staying power than the incentive of a bribe or reward.
Habits are powerful things. Most people have certain cues — like certain emotions, places, friends or times of day — that trigger a powerful urge to do a habit, whether it biting nails, smoking a cigarette, or eating a cookie. But habits can also be incredibly useful, if people can harness their power to shake bad behaviours in the longer run.
Another study of more than 1,500 kids in Chicago published in 2014, which was the subject of a Freakonomics podcast, supports the idea that they can. By giving kids who ate healthy a small reward — a pen, a rubber bracelet or a little plastic trophy — the researchers raised the proportion of children who chose a healthy snack from 17 per cent to about 75 per cent. But when the researchers stopped doling out the rewards, they found that more kids continued to choose the healthy option – suggesting that intervention might have helped to form a healthy habit.
The debate often comes down to the language people use — whether they call it bribery, a reward or an incentive.