Childhood temperament and family environment as predictors of internalizing & externalizing trajectories from ages 5 - 17
Journal of Abnormal Child Psychology, Oct,
2005 by Leslie D. Leve, Hyoun K. Kim, Katherine C.
Understanding how child characteristics and the family environment
relate to increases and decreases in problem behavior across childhood and adolescence is of key interest to developmental
and clinical psychologists.
One avenue to expand such knowledge is to examine the link between
specific child characteristics and specific problem behaviors. Several studies have shown that family environmental factors
might moderate the relationship between specific child temperamental characteristics and child internalizing and externalizing
behavior (Bates, Pettit, Dodge, & Ridge,
1998; Morris et al., 2002; Stoolmiller, 2001).
However, knowledge about the unique and interactive effects of temperamental
characteristics and family environment on change in internalizing and externalizing behavior from early childhood to late adolescence is limited. Further, we know little about whether boys and girls follow similar patterns of change and prediction.
this article, we examine the role of boys' and
girls' impulsivity, fear / shyness and family environment at age 5 on the development of internalizing and externalizing behavior through late adolescence.
and community-based studies suggest that internalizing behavior is relatively stable across childhood but increases somewhat
during adolescence (Bongers, Koot, van der
Ende, & Verhulst, 2003; Twenge & Nolen-Hoeksema, 2002). There is also evidence that internalizing trajectories vary by sex, with girls showing higher mean levels and sharper
increases in internalizing symptoms from childhood to adolescence than boys (Angold, Erkanli, Silberg, Eaves, & Costello, 2002; Keiley, Lofthouse, Bates, Dodge,
& Pettit, 2003).
of 310 studies using the Children's Depression Inventory (Kovacs, 1985) suggested that girls had slightly
fewer depressive symptoms in childhood but surpassed boys after age 13 (Twenge & Nolen-Hoeksema, 2002).
Predictors of change
shyness and emotional reactivity / inhibition to novelty have been shown to reliably predict concurrent and later internalizing problems at clinical and symptom
levels (Colder, Mott, & Berman, 2002;
Kagan, Snidman, Zentner, & Peterson, 1999; Prior, Smart, Sanson, & Oberklaid, 2000).
For example, Schwartz, Snidman and Kagan (1999) found that 61% of
the toddlers who avoided novelty displayed anxiety symptoms in adolescence, whereas only 27% of the toddlers who were uninhibited showed anxiety symptoms in adolescence. There is some indication that fear / shyness shares a common genetic liability with depression and anxiety, which may partially explain the predictive effects (Goldsmith & Lemery, 2000; Ono et al., 2002).
In addition, numerous studies have linked parental depression with child internalizing behavior (NICHD Early Child Care Research Network, 1999; Spence, Najman, Bor, O'Callaghan, & Williams, 2002). Thus, children with a depressed parent have a dual-risk for showing increases
in internalizing problems:
predisposed to have a fearful temperament and they're exposed to an environment in which the parent suffers from depression.
Exposure to harsh discipline and marital discord
also increases the likelihood that children will develop internalizing problems (Buehler, Anthony, Krishnakumar, & Stone, 1997; Capaldi, 1992; Davies & Windle,
2001; Shaw, Keenan, Vondra, Delliquadri, & Giovannelli, 1997).
studies have shown that temperament interacts with environmental characteristics to predict internalizing behavior. Morris
et al. (2002) found internalizing problems in children who were high in irritable distress and had mothers who used high levels of psychological control and Shaw et al. (1997) found that preschool boys' depressive behaviors were predicted by the interaction between high temperamental negative emotionality and exposure to parental conflict.
suggest that an emotional, fearful temperament interacts with characteristics of the family environment to predict internalizing problems. Additional
research is needed to examine the prediction of change through adolescence and to determine whether different processes operate by sex.
the developmental course of externalizing behavior have been more mixed. Different studies indicate decreasing or increasing
externalizing behavior from early childhood to adolescence depending on the measure, reporting agent and age span used (e.g., Loeber, Burke, Lahey, Winters, & Zera, 2000; Munson,
McMahon, & Spieker, 2001).
For example, Keiley, Howe, Dodge, Bates and Pettit (2001) used the externalizing scale
from the Child Behavior Checklist (CBCL; Achenbach,
1991) and found that externalizing behavior decreased
from kindergarten thru Grade 8 on the basis of mother reports but increased when teacher reports were examined.
In a recent, large-scale study examining the normative
developmental trajectories of externalizing behavior using the CBCL, Bongers
et al. (2003) found a significant reduction in child externalizing from ages 4 to 18.
studies find that boys have higher mean levels of externalizing behavior than girls (Broidy et al., 2003), though there is some evidence that growth rates may differ by sex, with the gender gap closing over time (Galambos, Baker, & Almeida, 2003).
Predictors of change
In the coercion model, the primary pathway to child and adolescent externalizing problems is through reciprocal, coercive interchanges
between the child and parent (Patterson,
Reid, & Dishion, 1992). Within this model, harsh
discipline has been identified as a key variable in accounting for variance in child externalizing outcomes (Eddy & Chamberlain, 2000; Keiley et al., 2003).
Conger and Elder (2001) examined change in delinquent behavior across 4 waves of data from ages 12/13 to 15/16 and found that harsh parenting predicted
growth trajectories of delinquency. Harsh parenting is often correlated with maternal depression and marital discord, but
each has been shown to have independent effects on externalizing behavior (Burke, 2003; Marchand, Hock, & Widaman, 2002).
parenting, maternal depression is related to growth in child externalizing problems (Munson et al., 2001; Owens & Shaw, 2003).
characteristics in early childhood also relate to externalizing problems in later childhood and adolescence (Schwartz, Snidman, & Kagan, 1996; Shaw, Owens, Giovannelli,
& Winslow, 2001). For example, lack of self-control in childhood was found to relate to teacher and parent reports of externalizing behavior problems assessed between
ages 9 and 15 (Caspi, Henry, McGee, Moffitt,
& Silva, 1995) and children rated as high on novelty
seeking were at greater risk for early adolescent externalizing behavior (Tremblay, Pihl, Vitaro, & Dobkin, 1994).
childhood fear / shyness might have a protective effect, as such characteristics are negatively associated with externalizing problems in adolescence (Moffitt, Caspi, Dickson, Silva, & Stanton, 1996; Schwartz et al., 1996).
As with internalizing
problems, research is beginning to show that family environment and temperamental characteristics interact to predict externalizing
problems. Bates et al. (1998) found that child impulsive / unmanageable temperament more strongly related to later externalizing problems when parents used unrestrictive,
noncontrolling parenting strategies.
Sandler and West (2000) found that inconsistent parental discipline was most strongly related to externalizing
problems for children high on impulsivity. Thus, family environment characteristics and impulsive temperamental characteristics appear to jointly contribute to later externalizing problems. However, effects on change and
sex-specific effects need to be explored into adolescence.
The Current Study
Bates et al.
(1998) noted that most developmental studies report only modest-to-moderate levels of associations
between temperament and child adjustment outcomes and between parenting and child adjustment outcomes. One explanation for
such effect sizes is the tendency to examine the independent contributions of temperament and family environment and to rely
on a single reporter (mother) of child temperament (Sanson, Hemphill, & Smart, 2004).
examined the independent and interactive contributions of specific temperamental characteristics and family environment characteristics
to externalizing and internalizing behavior. We extended prior work by incorporating growth modeling to test how temperament
interacts with family environment to predict change in externalizing and internalizing behavior over time in a sample of boys and girls.
The study had
two primary aims. First, we sought to examine the developmental trajectories of internalizing and externalizing
behavior in a normative sample of boys and girls. It was hypothesized that there would be significant increases in internalizing
behavior (especially for girls) and significant decreases in externalizing behavior from ages 5 to 17.
Second, we sought to examine childhood temperament, family environment and Temperament X Family Environment
interactions on age 17 internalizing and externalizing behavior and change in internalizing and externalizing behavior.
It was hypothesized
that the mean level of age17 internalizing behavior would be predicted by age 5 fear / shyness, age 5 family environment and their interaction and that the mean level of age 17 externalizing behavior would be predicted
by age 5 impulsive temperament, age 5 family environment and their interaction.
weren't made regarding which variables would predict growth in internalizing and externalizing over time owing to the lack
of prior work on this topic. Within these two aims, we also examined the role of gender. As Sanson et al. (2004) noted, there has been suggestive evidence (but no clear pattern) for sex differences in the
temperament - behavior problem link.
Participants were part of an ongoing longitudinal study of a community-based sample (N = 373). Two
cohorts of participants were originally recruited from a medium-sized city in the Pacific Northwest.
Cohort 1 was recruited via advertisements in local newspapers, mailed newsletters and flyers posted in public areas throughout
the local community. All families with 18 month-old children were invited to participate. The resulting sample (n = 166) matched the family size, income and occupational status statistics of the local area.
When the children
in Cohort 1 reached age 5, a second cohort of 5 year-old children (n = 207) was recruited using the
same recruitment procedures as with Cohort 1. Sample retention rates have remained high throughout the study. i.e., data were
collected on 97% of the original sample (n =
363) at the final assessment (age 17).
The ethnic diversity of the sample is similar to the region from which it was drawn:
- 88% Caucasian
- 7% mixed ethnic background
- 2% Hispanic
- 1% African American
- 1% Native American
- 1% Asian American
were 5, the mean ages for mothers and fathers were 33 and 36, respectively. At age 5, 79% of the children were living in families
with 2 biological parents. At age 17, 48% of the children were living with 2 biological parents and 9% of the children were
living with a biological parent and a stepparent.
When the children
were 5, the mean parental educational level was some college (without graduation) and mothers and fathers had mean occupation levels of 5 (e.g., clerical or sales worker) and 6 (e.g., technician, semiprofessional, or small business owner), respectively, on the Hollingshead 9-factor occupational
code (Hollingshead, 1975). Mean levels of education level and occupation didn't significantly increase by the age-17 assessment. Mean family
income levels were $18,000-24,000 per year at age 5 (1986-1988) and $40,000 per year at age 17 (1998-2001).
the sample comprised working-class and middle-class families. However, many of the families experienced significant socioeconomic
For example, over 10% of the families reported being homeless for at least 1 month (M = 5 months),
18% of the families had a gross annual income of less than $25,000/year between 1998 and 2001 - the average family income
in this area was $48,527 (U.S. Bureau of
the Census, 2000) - and 47% of mothers and 40% of fathers
had a high school degree or lower as their highest educational degree.
The analytic sample for this study consisted of 337 youths (174 boys; 163 girls) whose parents had completed
the CBCL in at least 3 of the following data collection points:
- age 5 (analytic sample n = 330)
- age 7 (n = 285)
- age 10 (n = 220)
- age 14 (n = 321)
- age 17 (n = 312)
A 1-year data-collection
hiatus occurred when some youths were 7 or 10, resulting in somewhat smaller sample sizes for those assessment waves. A mean
comparison test indicated that the mean levels of internalizing and externalizing behavior of the excluded youth weren't significantly
different from those included in the analytic sample at any time point.
At the age 5 assessment, families participated in a 2-hr home visit during which parents individually completed questionnaires
and participated in an interview. At all assessment waves, mothers and fathers completed a battery of questionnaires. Project
staff received a minimum of 25 hrs. of training prior to conducting interviews.
standardized data collection protocols was monitored via weekly team meetings and weekly one-on-one meetings with the project
coordinator. In addition, all instruments were checked for ambiguous or unintentionally skipped responses and any missing
data were then collected. There were no mean level differences between cohorts on the measures used in this report.
Internalizing and Externalizing Behavior Across
Time Internalizing and
externalizing behavior was measured using parent
report on the CBCL at all 5 assessments. Parents individually rated their child
on 112 behavior problems on a scale ranging from 0 (not true) to 2 (very true or often true). Externalizing
raw scores (aggressive & delinquent behavior
subscales; 33 items total) and internalizing raw scores
(the withdrawn, somatic complaints & anxiety/depressed
subscales; 32 items total) were examined in this report.
Scores were averaged across both parents to create an index score. (3) The mean interparent correlation was .51 for externalizing
and .35 for internalizing. Scores across all waves consistently demonstrated high internal reliability ([alpha] = .82-.95 for externalizing & .78-.92 for internalizing). Examination of the CBCL
T-scores indicated that the sample contained variability in the extent to which the youth exhibited clinical-level problems
in at least one wave: 19% demonstrated clinical-level externalizing symptoms and 20% demonstrated clinical-level internalizing
symptoms. Means and standard deviations for all variables reported here are included in Table I.
Age 5 Childhood Temperament
At age 5, the
Children's Behavior Questionnaire (CBQ; Rothbart,
Ahadi, Hershey, & Fisher, 2001) was administered.
The CBQ is
a 195-item, parent-report questionnaire that measures temperamental characteristics in 3 to 7 year-olds using a 7 point Likert-type
scale -1 (extremely untrue of your child) to 7 (extremely true of your child). The temperamental
dimensions assessed by the CBQ were derived from dimensions of temperament measurable in infancy and toddlerhood (Goldsmith, 1996; Rothbart, 1981).
For this study, two dimensions of temperament were included:
- the ability (or lack thereof) to control one's impulses
- the aversion to approach objects or people
We termed these temperament dimensions impulsivity and fear / shyness, respectively.
Based on these definitions and the face value
of items on the CBQ subscales, the impulsivity composite was comprised of the impulsivity subscale (13 items) and the reverse-coded inhibitory control
subscale (which measures
the ability to control impulses; 13 items).
Sample items for the 2 subscales, respectively, include "usually
rushes into an activity without thinking about it" and "can lower his / her voice when asked to do so."
The fear / shyness composite was comprised of the fear subscale (12 items) and the shyness subscale (13 items). Sample items for the 2 subscales, respectively, include "isn't afraid of large dogs &/or other animals" and "often prefers to watch rather than join other children playing."
for the 4 subscales was acceptable ([alpha] = .76-.94, M = .82). Internal consistencies for
the impulsivity and fear / shyness composite scales were .74 and .68, respectively. Because correlations between the mother and father ratings on both scales
were high (i.e., .58), they were aggregated to form an index of child temperament.
Age 5 Harsh Parental Discipline
At the age
5 assessment, parents were individually interviewed regarding discipline practices. Parents used a 5 point Likert-type scale
- 1 (never) to 5 (very often) - to
indicate how often they:
- swore at
- hit / slapped / spanked
their child. A harsh discipline composite was formed by aggregating these 3 items with 2 items
from a global interviewer rating.
interviewer ratings were the interviewer's responses following the 2-hr home visit to 2 questions:
- "How would you rate each
on a 5-point Likert-type scale ranging from 1 [very good] to 5 [poor])
- "To what extent did the
parent use physical punishment such as spanking"
on a 3-point scale with values of 1 [not mentioned], 2
[distinct impression] & 3 [mentioned directly]).
scale was converted to a 5-point scale (with
values of 1, 3, & 5) prior to analysis.
paternal harsh discipline scores correlated .62 and were thus aggregated to represent the average household discipline that
the child received at age 5. The internal consistency alpha of the harsh discipline scale was .71.
Age 5 Maternal Depressive Symptoms
At the age
5 assessment, mothers completed the Center for Epidemiological Studies of Depression Scale (CES-D; Radloff, 1977) to assess their depressive symptoms. The CES-D consists of 20 items to assess depressive symptomatology among adults
in the general population.
how they felt during the past week on a 4-point Likert-type scale ranging from 0 (rarely or none of the time) to 3 (most or all of the time); scores were summed across
items. The internal consistency alpha was .87.
Age 5 Marital Adjustment
At the age 5 assessment, we combined parents'
Dyadic Adjustment Scale score (DAS; Spanier,
1976) with their marital status to create a marital adjustment
variable. The DAS measures the overall quality of the marriage, including dyadic satisfaction, dyadic cohesion, dyadic consensus
and affectional expression across 32 items (usually
rated on a 6-point Likert-type scale). Internal consistency
alphas were .92 for mothers and .91 for fathers. The sample means for this study were nearly identical to mean levels for
married couples reported by Spanier. Because the mother and father ratings correlated .52, their scores were aggregated.
Marital status (0 [single] & 1 [married]) & DAS scores were then multiplied
to create a marital adjustment score, thus allowing single-parent families to be included in the analyses. (4)
Age 5 Family Income
income at child age-5, measured on a 10-point scale ranging from 0 (less than $5000 per year) to 9 (more than $54,000 per year), was included as a control variable.
employed latent growth curve modeling (LGC) using Mplus (Muthen & Muthen, 2001) to test the two study
aims to examine the developmental trajectories of internalizing and externalizing behaviors (age 5 -17) and to examine the
utility of 5 variables measured at age 5 (impulsivity,
fear / shyness, harsh discipline, maternal depressive symptoms and marital adjustment) in predicting age-17 internalizing / externalizing and change in
internalizing / externalizing. For both aims, parent ratings on the CBCL at ages
5, 7, 10, 14 and 17 were used as indicators to estimate two latent factors (intercept & slope).
factor was centered at age 17. Thus, the intercept factor can be interpreted as the level of internalizing / externalizing
behavior at age 17. Because all of the predictors were assessed at age 5, placing the intercept at age 17 allowed an examination
of prospective predictive patterns from childhood to late adolescence.
The slope factor
represents the rate of change in internalizing / externalizing behaviors (age 5-17 years). Models were
estimated using the full information maximum likelihood (FIML) estimator in Mplus, which allows the inclusion of participants
with partial data on the dependent variables.
No data imputations
were made on any of the predictor variables. Separate models were tested for boys and girls to examine differential change
and prediction by sex.
between the 5 predictors and internalizing / externalizing behavior for boys and girls are presented in Table II. For boys,
fear / shyness, harsh discipline, maternal depressive symptoms, and marital adjustment were significantly related to internalizing behavior
across time points, whereas impulsivity wasn't.
maternal depressive symptoms and marital adjustment were related to internalizing behaviors across time points, impulsivity
was significantly associated only with adolescent internalizing behavior and fear / shyness was related only to childhood internalizing behavior. Harsh parenting wasn't associated with girls' internalizing behavior
at any time point.
For externalizing behavior, impulsivity, harsh discipline, maternal depressive symptoms and marital adjustment were
strongly associated with boys and girls' externalizing behavior across time points. Fear / shyness showed a modest association with boys' externalizing behavior at age 7 and no association with girls' externalizing behavior
at any time point.
also significant correlations among the predictors (not shown in table). Impulsivity showed a significant
inverse relationship to fear / shyness for both sexes and correlated with harsh discipline for boys. Harsh discipline was related to maternal depressive symptoms
for boys. Finally, maternal depressive symptoms correlated negatively with marital adjustment for both sexes.
[FIGURE 1 OMITTED]
LGC Analyses: Developmental Trajectories of Internalizing / Externalizing
As is shown
in Fig. 1, the general trends of internalizing and externalizing behaviors (ages 5-17) appeared to be linear
for both sexes, suggesting that linear LGC models would fit the data well for each trajectory model.
are multiple types of linear growth models, two 2-factor linear growth models were tested to confirm the linear pattern: a
linear growth model and a linear spline growth model. In the linear growth model, the intercept factor loadings were all fixed
at 1 and the slope factor loadings were centered at age 17 and therefore fixed at -12, -10, -7, -3 & 0 (for ages 5, 7, 10, 14 & 17, respectively).
In the linear
spline growth model, the age 5 factor loading of the slope was fixed at -1 & the age17 factor loading was fixed at 0;
the other 3 loadings were freely estimated (B.
Muthen, personal communication, January 10, 2005). The linear spline model is a more general form than the linear
model because it allows for some types of nonlinear growth patterns (i.e., only the first & the final factor loadings are fixed). The unconditional growth trajectory models for internalizing and externalizing are described
below by sex.
Internalizing Trajectory for Boys
growth model of boys' internalizing behavior didn't fit the data well. [chi square](6) = 27.22, p =
.00. In contrast, the linear spline model had a significantly better fit, [chi square](3) = 5.04, p =
.17. By freeing 3 parameters, the chi-square statistic reduced from 27.22 to 5.04, nested [chi square] =
22.18, df = 3, p < .00.
indicated a significant improvement of fit over the linear model, the linear spline model was used for analyses on boys' internalizing
behavior. The means of the intercept and slope factor were 4.97 (z = 13.59, p < .001) & .49
(z = 1.26, ns), respectively.
represent the mean age17 score (4.97) & mean rate of change (.49) for boys' internalizing behavior. The nonsignificant
slope factor mean suggested that boys' internalizing behavior was relatively stable across this time period.
and slope factor had variances of 6.87 (z = 3.95,
p < .001) & .73 (z = 1.15, ns),
intercept factor variance indicated that there was significant individual variability in age17 internalizing, but the nonsignificant
slope factor variance indicated that there was little individual variance in change of internalizing behavior. The correlation
between the intercept & slope factor wasn't significant (1.48, z = 1.24, ns), suggesting that age17 internalizing
had no bearing on change in boys' internalizing behavior.
Internalizing Trajectory for Girls
model of girls' internalizing behavior didn't fit the data well, [chi square](6) = 29.55, p = .00,
but the linear spline model had a significantly better fit, [chi square](3) = 5.12, p = .16, nested [chi square] = 24.43, df = 3, p < .00. Therefore, the linear spline model was used for analyses on girls' internalizing behavior.
The means of
the intercept & slope factor were 6.20 (z
= 13.56, p < .001) & 1.09 (z = 2.31, p < .05), respectively. The significant positive slope factor mean indicated that, on average, girls' internalizing
behavior increased over time.
& slope factor had variances of 10.68 (z
= 4.01, p < .001) & .30 (z = .14, ns),
respectively, suggesting that there was significant variance in age17 internalizing behavior but nonsignificant variance in
change in internalizing behavior. The correlation between the intercept & slope factor was significant (4.13, z = 1.98, p < .05), suggesting that the higher the age17 internalizing behavior score, the steeper the rate of
increase over time.
Externalizing Trajectory for Boys
model of externalizing behavior for boys fit the data well, [chi square](9) = 7.48, p = .59. The linear spline
model for boys didn't result in a significant improvement over the linear model, [chi square](6) = 4.33,
p = .63, nested [chi square] = 3.15, df = 3, p > .25. Therefore, the linear model was used for analyses
of boys' externalizing trajectories.
The means of
the intercept & slope factor were 7.29 (z
= 13.22, p < .001) & -.16 (z = -3.56, p < .001), respectively. The negative slope factor mean indicated that there were significant decreases in boys'
externalizing behavior over time.
& slope factor had variances of 44.08 (z
= 7.05, p < .001) & .21 (z = 4.12, p < .001), respectively, indicating that there was significant variability in age17 externalizing behavior & change in
between age17 externalizing & the slope factor was significant (2.12, z = 4.55, p < .001), suggesting
that the higher the age17 externalizing behavior score, the steeper the rate of increase over time.
Externalizing Trajectory for Girls
model of externalizing behavior for girls fit the data well, [chi square](9) = 17.57, p = .04. The linear spline
model for girls didn't result in a significant improvement over the linear model, [chi square](6) = 13.92,
p = .03, nested [chi square] = 3.65, df = 3, p > .25.
Therefore, the linear model was used to analyze girls' externalizing trajectories.
The means of
the intercept and slope factor were 6.85 (z =
11.72, p < .001) and -.12 (z = -2.65, p < .001), respectively. The negative slope factor mean indicated that there were significant decreases in externalizing behavior
and slope factor had variances of 45.92 (z =
6.93, p < .001) and .19 (z = 4.21, p < .001), respectively, indicating that there was significant variability in age17 externalizing behavior and change in externalizing
behavior. The correlation between age17 externalizing behavior and the slope factor was significant (2.28, z = 4.84, p < .001), suggesting that the higher the age17 externalizing behavior score, the steeper the rate of increase over time.
LGC Analyses: Multivariate Prediction Models
To examine our second aim, 4 multivariate LGC models were tested to examine the utility of impulsivity, fear / shyness, harsh discipline, maternal depressive symptoms and marital adjustment (measured at age 5) in predicting boys' and girls' internalizing and externalizing growth curve
patterns. The control variable (family
income) was also included as a predictor
in each model.
In addition, prior to entry in the multivariate LGC models, the family environment predictors (maternal depressive symptoms, harsh discipline
& marital adjustment) were considered
individually for their interaction with the 2 temperament variables (impulsivity & fear / shyness) in each model.
If a Family Environment X Temperament interaction significantly predicted boys' or
girls' externalizing or internalizing when examined in isolation, the interaction term was included in that multivariate LGC
model. This method of determining which interaction terms to include was driven by the theoretical predictions in this study
and by the necessity to limit the number of interaction terms in the models given the number of possible interactions (Kim, Capaldi, & Stoolmiller, 2003).
Interaction terms that were significant in the multivariate LGC model were explored
post hoc by saving each individual's slope factor score on the dependent variable, conducting a median split on the temperament
variable and then plotting the relationship between the second predictor and the slope factor score by temperament group using
Internalizing Trajectory for Boys
In addition to the control variable and predictor variables, the Impulsivity X Marital Adjustment interaction term was significant
when tested in isolation and was thus added to this growth model.
Boys with higher levels of fear / shyness at age 5 who experienced harsh discipline and whose mothers reported high depressive symptoms at age
5 had higher levels of age17 internalizing behavior.
No variable significantly predicted change over time. The model accounted for 42%
of the variance in age17 internalizing behaviors and 9% of the variance in the rate of change. The parameter estimates, standard
errors and critical ratios for the multivariate LGC models for boys and girls' internalizing behavior are presented in Table
Internalizing Trajectory for Girls
No interaction terms were significant when tested in isolation for girls' internalizing
behavior; therefore, only the control variable and 5 predictors were included in this model. Fear / shyness and maternal depressive symptoms at age 5 were significantly and positively associated with the age17
Maternal depression at age 5 was significantly and positively related to
the rate of change and family income was significantly and negatively associated with the rate of change, suggesting that
girls whose mothers reported higher levels of depressive symptoms at age 5 and girls from lower income families showed greater
increases in internalizing behavior over time.
The model accounted for 49% of the variance in age17 internalizing behavior and 100%
of the variance in the rate of change. (Note that the variance for the slope was negative & therefore was fixed at 0. This common practice
resulted in a complete accounting of the slope variance.)
Externalizing Trajectory for Boys
In addition to the control variable and predictor variables, 2 interaction terms were included in this multivariate
- Impulsivity X Maternal
- Fear / Shyness X Maternalc Depressive Symptoms
As shown in Table IV, impulsivity and harsh discipline at age 5 were positively associated
with age17 externalizing behavior.
In addition, the Impulsivity X Maternal Depressive Symptoms interaction was negatively associated with age17 externalizing
behavior and the rate of change.
Analysis of this interaction indicated that only when impulsivity was low did maternal
depressive symptoms predict higher age17 externalizing behavior and increases in externalizing behavior over time. The model
accounted for 23% of the variance in age17 externalizing behavior and 18% of the variance in the rate of change.
Externalizing Trajectory for Girls
In addition to the control variable and predictor variables, three interaction terms were included in this multivariate
- Impulsivity X Harsh Discipline
- Impulsivity X Marital
- Fear / Shyness X Harsh Discipline
Impulsivity and the Impulsivity X Harsh Discipline interaction were positively associated
with age17 externalizing behavior, whereas family income, fear / shyness and the Fear / Shyness X Harsh Discipline interaction were negatively associated with age17 externalizing behavior.
The same variables were significant for the slope factor. analysis of the significant
interaction effects indicated that harsh discipline predicted higher age17 externalizing behavior and increases in externalizing
behavior when impulsivity was high but not when impulsivity was low.
In the same vein, harsh discipline at age 5 predicted higher age17 externalizing behavior and increases in externalizing
when fear / shyness was low but not when fear / shyness was high.
This model accounted for 46% of the variance in age17 externalizing behavior and 36%
of the variance in the rate of change. The Impulsivity and Fear / Shyness X Harsh Discipline interaction effects on girls' externalizing slopes are presented in Fig. 2.
Prior research has shown that temperament and family environmental characteristics such as parenting, parent depression and marital adjustment are among the strongest predictors of internalizing and externalizing behavior. Their importance is
highlighted by studies that have shown subsequent decreases in child internalizing / externalizing behavior when such processes
are targeted in interventions (Forgatch,
DeGarmo & Beldvas, in press; Stoolmiller, Eddy, & Reid,
is known about the role of temperament and how it might interact with family environmental characteristics to predict intervention efficacy. This report is a first
step to inform intervention studies by using growth curve modeling to examine how temperament and family environment interact to predict changes in problem behavior from age 5 to 17.
The LGC analyses suggested that girls' internalizing behavior
significantly increased over time, whereas boys' internalizing behavior remained fairly stable. This pattern of results resembles
that of prior studies.
For example, Bongers et al. (2003) found significant
increases for girls' but not boys' internalizing trajectories from ages 4 to 18 and reported mean levels at each time point
that were nearly identical to those in the current study.
The tendency for girls to show greater increases
in depression and anxiety than boys during adolescence has been theorized to relate to girls' increased vulnerability and reactivity to
stressful events involving others, girls' greater rumination about events and emotions and sex-differential socialization
pressures (Leadbeater, Blatt, & Quinlan,
1995; Nolen-Hoeksema, 1994; Zahn-Waxler, Klimes-Dougan, & Slattery, 2000).
Interpersonal stressors such as relationship problems
with peers or family members might be increasingly stressful during puberty, when girls develop more negative body images
than boys (Allgood Merten, Lewinsohn, &
Hops, 1990). Such biological and environmental factors
might precipitate increases in normative levels of girls' internalizing behavior during adolescence.
Conversely, externalizing behavior decreased for
both sexes over time, replicating prior studies using the CBCL in this age range
(e.g., Bongers et al., 2003). As with internalizing behavior, the mean levels of externalizing behavior at
each age were nearly identical to those reported in population-based studies (Bongers et al., 2003).
The decrease in externalizing behavior may have
resulted in part because externalizing behavior is likely to be more overt during early childhood but more covert during late
childhood and adolescence. For example, the frequency of overt physical aggression from childhood to adolescence generally
declines, but more concealed externalizing behaviors such as vandalism and theft increase (Lacourse et al., 2002; Tremblay, 2000).
Thus, parents may not know the full range of externalizing
behaviors in which adolescents engage and externalizing behavior may be reported as declining during adolescence. One limitation
of this study is the reliance of parent-reported (vs. self-reported) behavior
problems. In addition, serious delinquent behaviors that are more common during adolescence than childhood aren't captured
by the CBCL (e.g., robbery & physical
assault), which may also account for the decline found in our study.
This measurement bias might also affect the internalizing trajectories,
as parents might be better reporters of their child's internal symptoms (e.g., depression
and anxiety) during childhood, whereas children might be better reporters during adolescence.
Predictors of Age-17 Internalizing/Externalizing Behavior & Change
Maternal depression and child fear/shyness predicted internalizing behavior across a 12-year time span for both genders (and maternal
depression predicted increases in internalizing for girls), suggesting either that these are two very powerful
characteristics with long-term effects or that they set into place a series of environmental events that mediate the association
between early childhood characteristics and later internalizing behaviors.
The unfolding of adolescent internalizing behavior
might begin with the child's exposure at birth to a genetic and an environmental liability (i.e.,
a depressed parent). The genetic liability may translate into a fearful / shy temperament in early childhood, as there is evidence to suggest a genetic connection between early temperamental fearfulness and later
anxiety / depression (Goldsmith & Lemery, 2000; Ono et al.,
Mediating processes during later childhood and
adolescence might enhance the likelihood that early exposure to maternal depression and temperamental fear / shyness will result in the expression of internalizing problems during adolescence.
Examining the known mediators of internalizing
behavior, such as peer influences, environmental stress and pubertal timing (e.g., Ge et al., 1994; Mesman & Koot, 2001; Nolan,
Flynn, & Garber, 2003; Scaramella, Conger, & Simons, 1999) might help to further predict internalizing trajectories across
childhood and adolescence.
Regardless of the specific mediating mechanisms involved, the
current results suggest that childhood fear / shyness and maternal depression could be used as markers for screening boys and girls at greater risk for developing internalizing problems in adolescence.
In contrast to the relatively sex-invariant predictors found for internalizing behavior, some clear sex differences
were found in the prediction of externalizing behavior. For both sexes, higher age-5 impulsivity predicted higher age17 externalizing
behavior, replicating prior studies and suggesting the importance of individual vulnerabilities on risk for externalizing
problems. However, there were marked sex differences in the effect of harsh discipline on externalizing behavior.
Whereas age-5 harsh discipline directly predicted
boy's age17 externalizing behavior, it predicted girls' externalizing behavior only when it was accompanied by an individual
low fear / shyness or high impulsivity).
The absence of a main effect of harsh discipline of girls' externalizing behavior suggests that it might take more than pure
environmental risk for girls to show high levels of a maladaptive behavior that isn't well accepted from females in this society.
Beginning in toddlerhood, parents and teachers
respond very differently to boys' and girls' aggressive acts, with girls learning early that they'll receive more caregiver
attention for communicative (vs. aggressive) acts (Fagot, Hagan, Leinbach, & Kronsberg, 1985). Reinforcement for culturally defined, sex-appropriate behavior might thus suppress
externalizing behavior in girls, even when environmental risk factors are present (unless a temperamental predisposition to respond impulsively
or fearlessly is also present).
Conversely, for boys, harsh discipline and impulsivity had direct effects on age17 externalizing behavior and maternal depression emerged as a significant predictor of age17 externalizing behavior only when the child was low on impulsivity.
Impulsivity might have a sufficiently strong effect on externalizing behavior, such that maternal depression contributes significantly to externalizing problems only for boys without this individual vulnerability. The strength of
impulsivity as a predictor for boys might also explain why the combination of harsh discipline and impulsivity didn't predict
additional variance in boys' externalizing behavior.
Considering this effect in tandem with the independent
effect of maternal depression on boys' internalizing behavior suggests that the presence of maternal depression predicts later
internalizing behavior, whereas the combination of maternal depression with a child's nonimpulsive temperamental predisposition
predicts boys' externalizing behavior. As is described above, including mediators such as peer relations during middle childhood
might help explain these longitudinal effects.
Somewhat surprisingly, marital adjustment wasn't significant in any of our analyses, despite the fact that the bivariate correlations
suggested significant relations between marital adjustment and externalizing and internalizing in childhood and adolescence
for both genders. There was a strong, negative correlation between marital adjustment and maternal depression.
correlations between marital adjustment and the other predictors were nonsignificant, most approached significance. Thus,
the bivariate correlations between martial adjustment and internalizing / externalizing might represent variance that is largely
accounted for by the other predictors.
When all predictors
were included in the LGC models, little unique variance might have existed for marital adjustment. Additionally, it would
be worth considering alternative operationalizations of marital adjustment that incorporate the number of transitions (rather than absolute status) or that examine changes in marital adjustment over time.
The issue of change over time in predictors is further discussed in the last section of this
the results for internalizing and externalizing together, several distinctions should be noted. First, although the significant
predictors of behavior were somewhat similar for boys' and girls' internalizing behavior, sex differences emerged about which
specific family environmental variables interacted with temperament to predict externalizing behavior.
and low fear / shyness interacted with harsh discipline to predict girls' externalizing problems, whereas low impulsivity interacted with maternal depressive symptoms to predict boys' externalizing problems. This suggests separate gender pathways, with girls being more vulnerable to environments that have multiple reactive or insurgent characteristics (i.e., impulsivity, lack of fear and harsh discipline) and boys being more vulnerable to environments with multiple depressive, internal state, or emotional characteristics (i.e., lack of impulsivity and maternal
Additional research is needed to explore whether this sex difference can be replicated in
characteristics predicted changes in externalizing behavior but not internalizing behavior. This finding may indicate that
the relationship between fear / shyness and internalizing in boys is fairly stable across this development period.
However, there was no significant change in boys' internalizing scores over time. Furthermore, although
girls' internalizing behavior increased significantly over time, there was no significant variance around the changes scores.
Thus, the model predictors were competing for
a very small amount of variance in change in internalizing behavior. Inclusion of a sample selected for clinical levels of
internalizing problems might provide additional variance (and additional utility) in examining the predictors of change in internalizing behavior over time.
of effects also highlights the importance of examining the co-occurrence of externalizing and internalizing problems. Prior
research has shown that internalizing problems in childhood often lead to externalizing problems later in development (Mesman, Bongers, & Koot, 2001) and that externalizing and internalizing behavior co-occur at a high rate (Knox, King, Hanna, Logan, & Ghaziudin, 2000).
In addition, overlapping genetic factors underlie depressive and externalizing symptoms (O'Connor, McGuire, Reiss, Hetherington, & Plomin, 1998). An important next step is to examine the prediction to co-occurring problems
using growth curve modeling (e.g., Keiley
et al., 2003).
Further, it is important to identify unique predictors
of externalizing and internalizing behavior. Prior research indicates that temperamental withdrawal and parental internalizing
symptoms uniquely predict children's internalizing problems, whereas parenting stress uniquely predicts externalizing behavior (Mesman & Koot, 2000).
addition, the heterotypic nature of internalizing
and externalizing behavior poses methodological challenges for the investigation of change over time.
On the one hand, it's important to keep the measurement
items and scaling constant to measure true change. If different items or scaling were used across time, one couldn't be certain
whether growth / decline was truly being measured or whether the changes seen resulted from change in the measurement.
In addition, one assumption of current growth modeling programs is that the same methodological measurement / items
(i.e., same metrics) are used at each time point.
However, it's impossible to measure growth in
behaviors that change developmentally over time (e.g., language skills in young children or specific attachment behaviors) without adjusting the measurement of those behaviors.
If no change in measurement were allowed, many children would reach a ceiling (or floor) and growth over time would be misrepresented. Future methodological and statistical advances will greatly
benefit our understanding of growth in theoretical constructs that change developmentally over time.
Limitations and Future Directions
is the first to examine how temperament and the family environment interact to predict change in internalizing and externalizing behavior from early childhood through
However, some limitations should be noted. First, our temperament measurement wasn't collected until age 5, when the second cohort began the study. Given evidence of bidirectional effects
between parenting and child characteristics (Bates
et al., 1998; Ge et al., 1996), it's likely that such
effects had occurred prior to the onset of this study.
Nonetheless, there's evidence to suggest that temperamental characteristics make unique and independent contributions
to problem behavior, as studies beginning in infancy have found direct effects of temperament on problem behavior (Colder et al., 2002; Lemery, Essex,
& Smider, 2002). Thus, it's probable that the temperamental
effects found in this study represent both unique effects of temperament and interactive effects between temperament and family environment.
A related issue
concerns the extent to which the temperament measure (CBQ) taps a different construct than the CBCL given their overlapping
conceptual frameworks. Although there is some overlap in the individual items for the two scales, the vast majority of items
tap different behaviors or emotions.
In addition, the correlations between the CBQ and the CBCL ranged from
-.14 to .38 for internalizing and from -.07 to .49 for externalizing (see Table II), suggesting a significant amount of independence
between the two measures. Lemery et al. (2002) showed that, when CBQ temperament items and behavior problem items with confounding content were excluded from analysis, the correlations between temperamental characteristics and behavior problems were unaffected.
In addition, the predictive relationship between earlier temperament and later DSM-IV symptoms remains high with the purified CBQ, suggesting that the link between temperament and behavior problems isn't measurement specific. Thus, it's unlikely that the predictive utility of temperament on the outcomes found in this study resulted from overlapping measurement issues.
However, as with any study, our findings may be measurement specific and replication is needed. Our measures included mother
and father reports and global interviewer ratings for our predictors and aggregated mother and father reports for our outcome
measures. Our reliance on parent reports created significant method overlap. Increasing the method variance by including self-report
and observational data might offer additional utility in explaining problem behaviors.
Furthermore, the study predictors were measured at age 5 and demonstrated utility in predicting outcomes 12 years
later. However, many of our predictors have only modest stability across this time period.
Although including time-varying covariates was
beyond the scope of the current study, testing such models is an important next step in understanding the impact of temperament and family environment over time and understanding more about the mediating variables that may bridge early childhood characteristics with late adolescent outcomes.
Finally, our sample consisted of economically stressed, community-based families rather than a population-based or risk-selected sample. Although our study is one of very few studies
to include Caucasian families with limited financial resources, future work should focus on the equally important task of understanding how family environment and temperament interact in more ethnically diverse samples.