The influence of chronotype in the daily lives of young children.

Research on chronotypic differences has been conducted for many years, however, until recently, little attention has been paid to young children. The current study examined the influence of morningness-eveningness in the daily lives of 2 to 4 year olds (291 females, 230 males, 8 gender not given) via an online survey completed by 529 mothers from across the United States. The results replicated previous findings on chronotypic differences in sleep-wake patterns and the development of morningness-eveningness in early childhood. The influence of chronotype on sleep habits, daily routines and schedules was also explored. At both bed and wake times, mothers of evening type (E-type) children were more likely to report challenges. For a while, morning type (M-type) children tended to fall asleep easily and wake themselves up in the morning, E-types were more likely to show bedtime resistance, wake in a negative mood and have conflicts with their parents. In the morning, mothers of M-type children often stuck to their normal routine on days when the child had to be somewhere at 7:00 am, whereas mothers of E-type children employed different strategies to get their child up and out the door. Bedtime routines and daily schedules also differed by chronotype. Individual differences in morningness-eveningness and their impact on sleep-wake patterns and social interactions are evident early on. A greater understanding of how they affect the lives of young children and their future development is needed.

Chronotype and the transition to college life.

Social synchronizers of morningness-eveningness, or chronotype, begin to change during the developmental transition from adolescence to college life. The current study examined how these changes related to the sleep/wake patterns of 220 undergraduates (93 males/122 females) ranging in age from 18 to 29 yrs at a private university. Coping strategies students used to deal with early morning commitments and familial conflict over sleep patterns were also examined. Results revealed that evening chronotypes were more likely to report conflict with parents in junior high school and high school over going to bed and waking, followed by a shift to a later sleep/wake pattern in college. They also reported adjusting their schedules and using more coping strategies to accommodate their evening bias. Morning chronotypes, whose routines easily fit a conventional morning schedule, reported little change in schedules and sleep patterns from junior high school to college, and used fewer coping strategies in response to early morning commitments. The shift in social zeitgebers from junior high school to college are significant, and yet little research has examined the effect these changes can have on students' adjustment to college life and the role that chronotype plays in this process. Because students' ability to cope with these changes will ultimately influence how successful they are in their various endeavors, a greater understanding of how chronotype is related to adaptive functioning across this developmental period is needed.

A salivary collection method for young children.

Salivary assays are a major physiological measure in studies of child development. Traditional collection techniques have generally involved children chewing on sterile dental cotton rolls. However, research suggests that, for an accurate assay, potential contaminants need to be minimized, both from oral stimulants and the collection device. Moreover, the use of cotton requires that additional saliva be collected to compensate for the amount absorbed by the cotton itself. For these reasons I adapted the passive drooling collection protocol for use with young children. To this end, a game was created which involves frog puppets constructed so that a funnel, which serves as the frog's mouth, connects to a cryogenic vial housed in the frog's body. Details on the specifics of this methodology as well as the effectiveness of this approach are discussed.

The influence of emotion regulation, level of shyness, and habituation on the neuroendocrine response of three-year-old children.

The current study investigated the temperamental dispositions of 53 three-year-old children (27 males, 26 females) and their behavioral and physiological responses to a stranger approach situation. Results indicated that elevations in cortisol were predicted by the child's level of shyness (with both shy and bold children showing elevations), better emotion regulation, and attendance at daycare which was believed to measure habituation to interactions with unknown adults in a playroom setting. In addition, the majority of children, both shy and bold, had cortisol levels that had begun to recover by fifteen minutes after the initial assessment. This suggests that the major concern for inhibited children is not weak regulation, but rather more frequent activation of the HPA system in response to novelty and a perceptual framework that expects fear.

The influence of temperamental reactivity and situational context on the emotion-regulatory abilities of 3-year-old children.

Although much research has been conducted on emotion regulation, little work in the preschool period has examined the interrelationships between emotion regulation, temperamental reactivity, and situational context. The authors investigated the temperamental dispositions of fifty-three 3-year-old children (27 boys, 26 girls) and their behavioral responses to several challenging tasks (i.e., stranger-approach situation, busy-caregiver paradigm, and delay-of-gratification task). Results indicated that both situational context and temperamental reactivity influenced the type of emotion-regulatory strategy used and that those relationships were best understood within a developmental framework. Moreover, the authors found that girls displayed more comforting strategies, suggesting that gender differences in emotion regulation may exist.