Everybody knows that eating a lot of candy makes children "hyperactive". If they didn't eat so many sweets, they wouldn't be like that, and when they get lots of sweets, their behavior is just awful. Yes, we do know that... or don't we? Lots of parents have had this issue on their minds over the weekend, although because Halloween fell on a Saturday this year, teachers may feel they got a break.
As usual, to think straight about a belief of this kind, we need to think it over carefully. In fact, careful research on this topic does not show that eating sweets is related to children's activity levels or their attentiveness in the classroom or at home. So, why are we so ready to jump to the conclusion that sugar makes kids wild? Let's think about some possible reasons for this incorrect conclusion.
1. Confusing language: Everyone has heard the term "hyperactive" --- sometimes abbreviated by parents and teachers to a simple "hyper". It's something that everyone knows children can be. Some of them take medicine so they won't be that way, so it makes sense that taking something else, like candy, could cause their behavior. But the fact is that being active is not the same as being "hyperactive". Almost all children are more active than adults, and often more active than adults like, but they are not "hyperactive" (a specific diagnosis) even when they are hard on the furniture or our nerves. Like adults, normal children are different from each other in their activity levels, and each child can be different depending on circumstances. Eating candy is only one of many factors that might affect a child's behavior, but the way we talk about activity can confuse the way we think about it.
2. Confounded variables: When many factors occur at the same time, it's not logical to pick just one of them as the sole cause of any change, unless you have good evidence that that one factor is responsible for what happens. That evidence is hard to get when events occur naturally instead of in the laboratory, so we usually need to consider that causes can be confounded or confused with each other.
Halloween is definitely a time when the factor of candy consumption is very much confounded or confused with other factors that might cause behavior changes. Here are some of them:
When children are excited, and when they anticipate a candy feast, they tend not to eat their regular meals. Lack of ordinary nutrition is a factor that is confounded with candy consumption on Halloween. It's probably not very likely that missing a meal or two causes much immediate behavior change, but it could happen.
When children stay up later than usual, they generally do not sleep late the next day, so their behavior can be affected.
When children are frightened (even pleasurably scared), their sleep and behavior can be affected.
When parents are worried about having children go out trick-or-treating, and concerned about examining every piece of candy before it's eaten, some real anxiety can intrude. (Not to imply that parents should not do this. We're just looking for confounding variables.)
When parents and teachers believe that children will behave badly, they may show their beliefs by being extra quick to notice and squelch undesirable behavior, or even by telling children, "We knew you'd be terrors today". These adult behaviors can also affect the way children act.
When children are told that candy will make them act up, they may "know" this is true, and comply with the rule adults have given them.
3. Isolating the candy variable: Given that there are so many confounding variables, how would we go about figuring out whether sugar causes changes in children's behavior? This could not be done in any ordinary setting where children know that they're eating candy, or the adults around them are aware of what they eat. The only way this could be done (and it has been done) is to use a setting like a summer camp where children have no access to food outside the planned diet. Then, you give all the children sugar-free food. Assigning children to conditions at random, you give each child a tasteless daily supplement that contains either sugar or some inactive substance. Only one person knows which children get sugar, and that person has no contact with the children, but simply writes names on containers of supplements. Someone else gives the children their supplements, and another uninformed person rates each child's behavior each day. At the end of a week or two, the ratings for the two groups are compared. If, under these circumstances, the children receiving sugar were rated as significantly more active, less attentive, or in some way "worse" than the other group, that would be support for the idea that "sugar causes hyperactivity"-- but that's not the way it has ever worked out.
Funny, no one ever seems to advance the hypothesis that adults who eat some of the kids' candy then become crabby and irritable and judge children to be misbehaving when in fact they're acting quite normal. Could that be the problem? Just kidding... I think!
