Steven S. Robertson

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The normal development of adaptive behavior in humans depends on the integration of visual attention and body movement, yet little is known about the initial state of movement-attention coupling at the beginning of postnatal life. We studied 1- and 3-month-old infants during extended periods of visual exploration and found that spontaneous shifts of gaze(More)
Available online 1 April 2009 Previous work has found that many young children show different patterns of production of the hormone cortisol, which is sensitive to stress and challenge, on days when they are at child care compared with days when they are at home. At home, preschool age children typically show a decreasing pattern of cortisol production(More)
The spontaneous movements of human fetuses were studied longitudinally between 21 and 41 weeks of gestation. At each age, spectral analysis of the fluctuations in fetal movement revealed strong cyclic patterns. The frequency of the dominant motor rhythms ranged from .13 to 1.91 cycles per minute. The strength of oscillations between .18 and 1.02 cycles per(More)
The continuous presence of a supportive companion (doula) during labor and delivery in two studies in Guatemala shortened labor and reduced the need for cesarean section and other interventions. In a US hospital with modern obstetric practices, 412 healthy nulliparous women in labor were randomly assigned to a supported group (n = 212) that received the(More)
Because continuous social support during labour is a component of care in many societies but inconsistent in our own, the clinical effect of support during labour on maternal and neonatal morbidity were studied. Social support was provided by female companions. Four hundred and sixty five healthy primigravidous women were enrolled using a randomised design.(More)
Fluctuations in body movement and visual inspection were measured over minutes in 3-month-old infants to look for evidence of coupling. In Experiment 1, infants (n = 12) looked ad libitum at two identical pictures for an average of 7.3 min. Analysis of the spontaneous fluctuations in movement and inspection revealed that they were inversely coupled:(More)
Elevated afternoon levels of cortisol have been found repeatedly in children during child care. However, it is unclear whether these elevations have any consequences. Because physiologic stress systems and the immune system are functionally linked, we examined the relationship between salivary cortisol concentration and antibody secretion across the day at(More)
The spontaneous movement of 41 healthy human newborns was analyzed for cyclic patterns during different behavioral states and also compared to similar data obtained during their last few months of gestation. Spectral analysis was used to identify and quantify the motility cycles, except in quiet sleep, for which the instantaneous frequency of the isolated(More)
Human infants actively forage for visual information from the moment of birth onward. Although we know a great deal about how stimulus characteristics influence looking behavior in the first few postnatal weeks, we know much less about the intrinsic dynamics of the behavior. Here we show that a simple stochastic dynamical system acts quantitatively like(More)
Does real time coupling between mental and physical activity early in development have functional significance? To address this question, we examined the habituation of visual attention and the subsequent response to change in two groups of 3-month-olds with different patterns of movement-attention coupling. In suppressors, the typical decrease in body(More)