Warren O. Eaton

Sex differences in the activity level of infants

A gender difference in motor activity level (AL) is well established for children, but questions about the existence and nature of an infant sex difference remain. To assess these questions, we applied meta-analytic procedures to summarize 46 infancy studies comprising 78 male–female motor activity comparisons. Our results showed that, as with children, male infants were more active than females. Objective measures of infant AL estimated the size of this difference to be 0.2 standard deviations, though subjective parent-report measures estimated the difference to be smaller. We argue that this early sex difference in activity level is biologically based. However, socialization processes, such as gender-differentiated expectations and experiences, in conjunction with further sex-differentiated biological developments, amplify this early difference to produce the larger gender differences in activity found during childhood. Copyright

Are sex differences in child motor activity level a function of sex differences in maturational status

By virtue of being farther along a developmental path for motor activity level, girls may appear to be the less active sex when compared to less physically mature but same-aged boys. If so, observed sex differences in activity level may be an epiphenomenon of sex differences in maturity related declines in AL. To test this hypothesis and the associated premise that females would be more mature and less active than males, the customary activity levels and relative physical maturities of 83 5-8-year-olds were assessed. Relative maturity (percentage of estimated adult height attained) was negatively related to activity level, and girls were both less motorically active and more mature than boys. Though reduced in magnitude, the sex effect remained significant after maturity was added as a predictor of AL. Thus, sex differences are not due only to maturity differences but may be partially mediated by them.

Effect of respite care on dementia and nondementia patients and their caregivers.

The impact of a respite program on the cognitive and physical functioning of dementia and nondementia patients, and on the burden perceived by their caregivers, was assessed in a pretest-posttest design. A total of 55 caregivers were interviewed twice, 5 weeks apart. In the respite group, the caregivers patient experienced a 2-week respite stay in a nursing home during the 5-week interval, whereas in the waiting-list comparison group, the patient experienced ongoing in-home care during the interval. We hypothesized that patient diagnosis (dementia vs. nondementia) would interact with respite exposure, with nondementia patients showing more improvement from respite than dementia patients. Regardless of diagnosis, however, positive effects from respite exposure were found for caregiver reports of the patients memory and behavior.

Parent and actometer measures of motor activity level in the young infant

Abstract Motor activity level is one dimension of infant temperament for which parental judgment can be validated against a truly independent criterion. Two studies were conducted, the first involving a 27-min sample of behavior in a structured, attention-getting situation, and the second involving a 24-hr sample of in-home behavior. In both studies, parent perception of the 3- or 4-month-old as measured by the Activity Level (AL) scale of the Rothbart Infant Behavior Questionnaire was compared to the composited readings from four mechanical motion recorders (actometers) worn, one per limb, by the infant. The AL scale did not correlate with the actometer measure, r =.05 and r =.00, and the expected convergence of the 3-month version of the IBQ activity scale with its mechanical counterpart was not found. In the 24-hr study, birth order and ponderal index were significantly correlated with 24-hr actometer scores; first-borns and thin infants were most active.

Motor activity level and behavioural control in young children

How do young children’s typical levels of physical movement relate to their ability to inhibit task-inappropriate behavioural responses? This question was investigated with a cross-sectional sample of 85 children, 4- to 6-years of age. Children’s typical levels of activity were assessed with actometers, mechanical measures of movement frequency. Multiple measures of contra-habitual task performance, reflecting children’s ability to inhibit the typical response associated with a task and to execute a less typical response, were aggregated. Procedurally similar control tasks, not dependent on the inhibition of behavioural responses, were also assessed. Contra-habitual task performance was positively and uniquely related to activity level, and an age by movement interaction showed that this relation was most reliable among the younger children in our sample. Young children’s motor activity is associated with enhanced, not diminished behavioural control.

Prenatal activity level as a temperament dimension? Individual differences and developmental functions in fetal movement☆

Abstract Fetal motor activity may meet the criteria for a temperamental trait, and our purpose was to determine if individual differences in fetal movement (FM) generalize across gestational weeks. Mother counts of FM allow extensive behavioral sampling in natural settings and, as shown in a review of 13 studies comparing maternal counts to simultaneous instrumented measures, are veridical. Daily FM counts were collected from 46 women for gestational weeks 28 to 39. Individual differences were highly significant and stable over weeks. A curvilinear developmental function, peaking at 34 weeks, was also significant. Perinatal continuity in these individual differences has yet to be demonstrated; nonetheless, customary fetal activity meets generally accepted temperament criteria: Individual differences appear early in life, reflect broad behavioral tendencies, have a constitutional foundation, and demonstrate continuity of expression across time.

Scheme for Observing Activity Level: Reliability and Convergent Validity

The Scheme for Observing Activity Level (SOAL) is described. Nine mutually exclusive combinations of posture and movement intensity are defined for use in observational studies. Duration of time spent in each category is multiplied by energy expenditure estimates drawn from the empirical literature, and the products are summed to create the SOAL score. Interobserver reliability for the SOAL is evaluated in three studies with preschool children and is found to range from .90 to .94. SOAL scores also converged, as hypothesized, with observer rankings, a mechanical motion recorder measure, and teacher rankings. It is concluded that the SOAL is practical and reliable for use in observational studies that utilize real-time data collection.

Instrumented motor activity measurement of the young infant in the home: Validity and reliability☆

Abstract Commercially available motion recorders were assessed with a mechanical shaker and found to be valid and reliable. Each of the 43 1- and 2-month-olds wore four instruments, one per limb, in the home for 48 hours. The instruments reliably discriminated differences between limbs and between individual infants.

Gender understanding and sex-role stereotyping in preschoolers: Implications for caregivers

A research review indicates that although most preschoolers see gender as a relatively stable personal attribute, they do not realize that gender is constant despite stylistic and behavioral variations. This misunderstanding contributes to a period of sex-role inflexibility. Implications for child care are discussed.

Transitions in Breastfeeding: Daily Parent Diaries Provide Evidence of Behavior Over Time

This study addressed a key question for assessing breastfeeding duration: at what point is an infant considered no longer exclusively breastfed or no longer breastfed at all? Mothers provided longitudinal infant feeding data via daily checklists. Transitions between exclusive to partial breastfeeding and partial to no breastfeeding were compared across 11 time periods for 10 age groups of infants. Daily transitions between exclusive and partial breastfeeding were common, especially for infants 6 months of age and younger, and transitions from partial to no breastfeeding occurred much more quickly than transitions from exclusive to partial breast-feeding. Ages at supplementation and weaning calculated in 1-day or 7-day spans correlated highly (intraclass correlation = .99). These results support the Breastfeeding Definitions and Data Collection Periods guideline recently developed by the Breastfeeding Committee for Canada and may bring the breastfeeding research and clinical communities closer to a consensus on the definition of breastfeeding over time.