778 vII. APPLICATIONS  AND  IMPLICATIONS
IQ are at least moderately correlated with 
what they will be decades later. Tempera -
ment —individual differences in emotional 
responsiveness—  is heavily influenced by 
biological differences (genetic, hormonal, 
and early environment nutrition and tox -
ins) and forms a basis for later personality 
traits and for health. Approaches typically 
have included dimensions reflecting negative 
emotionality (related to later emotional sta -
bility), positive emotionality (related to later 
extraversion and optimism), and impulsivity 
and effortful control (related to later consci -
entiousness) (e.g., Ahadi & Rothbart, 1994; 
Caspi, 1998). However, any one tempera -
ment may relate to more than one adult trait, 
depending on the early environments. There 
is great potential for further study of the ef -
fects of early-life temperament on personal -
ity and health over long time intervals.
One intriguing aspect involves transgen -
erational effects. The life of any one indi -
vidual begins in utero,  but the life-  course 
perspective on health should also consider 
maternal health and behavior, and the 
mother’s social context prior to, during, and 
after pregnancy. For example, women with 
high stress prenatally were substantially 
more likely to have low-  birthweight infants 
and to deliver preterm compared to women 
with low stress (Lobel, Dunkel-  Schetter, & 
Scrimshaw, 1992). Furthermore, women 
who were least optimistic delivered infants 
of significantly lower birthweight, with re -
searchers controlling for a variety of other 
predictors (Lobel, DeVincent, Kaminer, & 
Meyer, 2000). In turn, studies in rats and 
other mammals document long-  lasting ef -
fects of prenatal exposure to stress hor -
mones and sex hormones. Famine caused 
by wartime occupation of The Netherlands 
in 1944 led to significant long-term impacts 
of intrauterine deprivation, interacting with 
postwar prosperity that these children met 
(Schulz, 2010). We foresee great value from 
multigenerational studies of personality and 
health that enable the study of how paren -
tal characteristics and experience impact the 
personality and health of their children.
Childhood is also increasingly well docu -
mented as important to understanding tra -
jectories to health and longevity decades 
later, with childhood personality having a 
surprisingly powerful influence on these 
trajectories. Longitudinal studies of child -hood personality were initiated years before 
the contemporary dominance of the five- 
factor model of personality (Measelle, John, 
Ablow, Cowan, & Cowan, 2005; Mervielde 
& DeFruyt, 2002). Accordingly, it makes 
sense to group studies according to broader 
categories of effortful control (conscien -
tiousness), negative emotionality, and posi -
tive emotionality.
Conscientiousness
The health significance of childhood levels 
of restraint and prudence as embodied in 
the trait of conscientiousness first became 
apparent in follow-  ups to and analyses of 
archival data collected for the Terman Life 
Cycle Study. Due to extensive early measure -
ment and lifelong follow-  up, these data offer 
an unprecedented opportunity to examine 
the influence of childhood personality on 
longevity. Starting in 1921, 1,528 Califor -
nia schoolchildren, of average age 11 years, 
were recruited for a prospective study of the 
growing up of gifted children. Friedman and 
colleagues were able to track down and gen -
erate longevity data and to construct and 
validate measures of childhood personality 
from the parent and teacher data available 
in the archives that were meaningful in con -
temporary terms of the five-  factor model 
(Friedman et al., 1993; Martin & Friedman, 
2000). The most striking finding from these 
studies was that childhood conscientious -
ness predicted longevity across the lifespan 
and emerged as a risk factor for all-cause 
mortality of the same magnitude as ones that 
are widely accepted by the medical profes -
sion, such as serum cholesterol and elevated 
resting systolic blood pressure (Friedman 
et al., 1993; Friedman, Tucker, Schwartz, 
Tomlinson-  Keasy, et al., 1995).
Perhaps because a reliable and valid as -
sessment was being used successfully to pre -
dict such a reliable long-term and important 
outcome (longevity), this finding has since 
been replicated successfully in a variety of 
different samples and has helped launch a 
wide range of research programs investigat -
ing conscientiousness and health. The long-
term effects of childhood conscientiousness 
on adult health, as well as its relations to 
unhealthy habits such as smoking in the Ter -
man sample (Tucker et al., 1995), were con -