Kids can seem as different as ladybugs and killer bees -- and about as disparate in their behavior.

Some are easy to handle; others are tough even for seasoned parents and teachers to manage.

And recent research seems to show that children may be predisposed to their behavior from an early age.

By studying data compiled on children at 6 months of age and then 12 years later, a pair of professors has found correlations between infants' fussiness and later behavior problems in school.

"These findings indicate that some children are predisposed to social and emotional problems that manifest themselves in school," said Dr. Roy Martin, a professor of educational psychology at The University of Georgia.

The study's results may help parents and teachers create environments for these "difficult" children that reduce the chances of problem behavior later, Martin said.

"The central message of temperament research is not that some behaviors have a genetic basis, or that behavior is predictable over a long period of time," he said. "It's that, because of these predispositions, environmental adjustment may be critical for the healthy development of children. This message is highly relevant to schools."

Working with Dr. Matti Huttunen, a psychiatrist at the University of Helsinki in Finland, Martin has analyzed data collected on hundreds of infants born in Helsinki during a 12-month period.

In Huttunen's research, begun in 1976, mothers were asked to rate their 6-month-old infants in several categories: general crying and fussiness; how regular the infants were in feeding, sleeping and elimination; sensitivity to wet and soiled diapers; and their activity level and emotional intensity.

After 12 years, when the infants had reached the sixth grade, Huttunen visited schools throughout metropolitan Helsinki and asked teachers to complete a questionnaire designed to measure their impressions of student behavior. The teachers evaluated their students for school performance, withdrawn and depressed behavior, and dangerous and quarrelsome behavior.

The Helsinki Longitudinal Temperament Study used temperament assessed at age 6 months to predict teacher ratings of temperament and behavior problems at age 12 years.

Huttunen obtained data from about 1,372 children between the ages of 6 and 8 months, born between July 1, 1975, and June 30, 1976, in two major obstetrical clinics in Helsinki. The parents' ratings he obtained were based on a Finnish version of the Carey Infant Temperament Questionnaire. The survey was administered when mothers brought their infants to clinics for well-baby checkups, which are provided free in Finland.

During April and May of 1988, when these children were 11 to 12 years old, Huttunen contacted a number of schools in the area served by these clinics. More than 125 teachers in 69 schools rated 1,306 students.

"This is not a longitudinal study in the traditional sense; a sample of children initially identified was not followed over time," Martin said. "Rather, a sample of children from one location was assessed, and 12 years later children from the same location were assessed. The data reported are based on 231 children who were assessed at both periods -- that is, at 6 months and at 12 years."

Among their findings:

Males -- Boys who were active and emotionally intense at 6 months old had more behavior problems during preadolescence. "That includes what I call `school performance problems' -- paying attention in class, motivation to learn -- as well as behavior problems," Martin said.

The strongest relationship was between 6-month activity/emotional intensity and 12-year reactivity, he said.

"Infant males rated as less active and mild in emotional intensity were rated as 12-year-olds as less likely to argue with other children in play, less likely to overreact in stressful situations, and less likely to be sensitive to environmental temperature changes," he said.

Females -- Girls who are more sensitive and fussy about wet diapers tend to be more anxious and depressed at age 12.

"There's a very strong relationship here," Martin said. "The more fussy the girl infants were, the more school performance problems they had. With girls, the connection seems to be how easily their nervous systems are irritated. These very sensitive little girls seem to become more anxious later on."

Girls, rated as infants as more irregular in patterns of sleep, times of hunger and bowel movements, were rated as 12-year-olds as less task-persistent, more distractible and more active.

However, "the correlations are low," Martin said. "They were obtained against a background of incredible measurement noise. Parents filled out the questionnaires while waiting to have their baby seen in a health clinic -- an unstructured situation that provides poor control over attention and motivation."

Other contributions to the "noise" level include the age of the questionnaire and the fact that it had been translated into Finnish.

"Given these problems, the prediction task was like looking through a home telescope toward a distant planet on a cloudy night," Martin said. "Under these circumstances, it's not the clarity of the image that's important; it's that you see any image at all.

"The low correlations are important: not because of their size but because they exist at all," he said.

Future Uses of the Data

Martin said the study was conducted primarily to advance the theoretical understanding of child development.

"It's important to know the development pathways that lead to problem behaviors; we need to know which factors raise the probability that a child will end up with problem behavior," he said.

"We hope it will lead to some of these more practical applications," Martin said. "This includes engaging in some sort of supportive program to help prevent problems for children you identify early as at risk for these problems."

This information may help parents and teachers understand the behavior of children in their care.

"Such information, communicated carefully, could help caretakers understand particular sensitivities of their children and the kinds of environments that might lead to problems. This approach places emphasis on prevention," Martin said.

"Dr. Huttunen and I see these preliminary findings as the first step in a series of studies where we look at the fact of very early personality/temperamental differences in children as they affect physical and mental health issues," he said.

The next step in the research involves collecting health records on all of the children who were assessed at 6 months. School nurses in Finland keep careful records of childhood illnesses and accidents, Martin said.

"We believe some of these behaviors might be related to things like accident rates of children and to some diseases strongly associated with stress reactions: asthma, a variety of allergic reactions and a susceptibility to infectious diseases," he said.

Drs. Martin and Huttunen also plan to take advantage of Finland's careful records of mental health admissions and criminal activity.

"We'll assure the anonymity of the individual, but we're trying to gain access to those records and see if the data we obtain can predict these things, based on comparison with earlier data," Martin said.

But just how is it possible for researchers to be able to predict that a child's behavior at 6 months of age will affect his behavior at 12 years?

"We think the most plausible explanation for this kind of relationship begins with some genetic differences in children. These genetic differences create individual differences in behavior," Martin said. "These behaviors then cause adverse social reactions from parents and peers, which then create the behavior problems we see at age 12."

For example: An emotionally intense baby may cause the mother to begin acting differently -- not spending as much time with the child, treating the child a little more harshly or reacting with slightly more frustration. The problem worsens if emotional intensity and behavior problems created by the mother-child relationship then create similar problems with the child's peers.

"The important point here is that we don't think behavior problems are a direct effect of the very early temperamental behavior, but these behaviors have social consequences that cause the behavior problems," Martin said.