Early human occupation of Australia's eastern seaboard.

Secure archaeological evidence for human occupation on the eastern seaboard of Australia before ~ 25,000 years ago has proven elusive. This has prompted some researchers to argue that the coastal margins remained uninhabited prior to 25 ka. Here we show evidence for human occupation beginning between 30 ± 6 and 49 ± 8 ka at Wallen Wallen Creek (WWC), and at Middle Canalpin Creek (MCA20) between 38 ± 8 and 41 ± 8 ka. Both sites are located on the western side of Minjerribah (North Stradbroke Island), the second largest sand island in the world, isolated by rising sea levels in the early Holocene. The earliest occupation phase at both sites consists of charcoal and heavily retouched stone artefacts made from exotic raw materials. Heat-treatment of imported silcrete artefacts first appeared in sediment dated to ~ 30,000 years ago, making these amongst Australia's oldest dated heat-treated artefacts. An early human presence on Minjerribah is further suggested by palaeoenvironmental records of anthropogenic burning beginning by 45,000 years ago. These new chronologies from sites on a remnant portion of the continental margin confirm early human occupation along Sahul's now-drowned eastern continental shelf.

Preterm Birth and Other Measures of Infant Biological Vulnerability: Associations with Maternal Sensitivity and Infant Cognitive Development.

INTRODUCTION: Low birth weight (LBW), biological vulnerability that includes preterm birth (PTB) and small for gestational age (SGA), is associated with reduced maternal sensitivity ("making accurate inferences about an infant's physical and emotional needs and responding appropriately") and impaired infant cognitive development. However, research does not examine if preterm birth, SGA, or both drive these associations. This study separated these measures of biological vulnerability to examine associations of LBW, PTB, and SGA with maternal sensitivity and infant cognitive development (controlling for maternal depression, breastfeeding, and demographic covariates). METHODS: The sample included 6900 9-month-old infants from the Early Childhood Longitudinal Study-Birth Cohort and used birth certificate data, maternal interviews, assessments of maternal sensitivity and infant cognitive development. Multiple linear regressions examined LBW, PTB, and SGA associations with concurrent measures of maternal sensitivity and infant cognition. RESULTS: Of the biological vulnerabilities, preterm birth had the strongest negative association with maternal sensitivity (F1,6450 = 29.48 versus 15.33 and 5.51, ps < .001) and infant cognitive development (F1,6450) = 390.65 versus 248.02 and 14.43, ps < .001). In the final regression model, preterm birth and maternal sensitivity were uniquely associated with infant cognitive development (R2 = .05, p < .001), after controlling for maternal depression, breastfeeding, and demographics. CONCLUSION: In this nationally representative infant sample infants, PTB had a stronger negative association with both maternal sensitivity and infant cognitive development in comparison to SGA or LBW. The LBW designation combines infants born preterm with SGA infants, potentially minimizing differences in developmental outcomes of PTB and SGA infants.

Does breastfeeding account for the association between maternal sensitivity and infant cognitive development in a large, nationally representative cohort?

BACKGROUND: Previous research has established that exposure to high maternal sensitivity is positively associated with advances in infant cognitive development. However, there are many fixed and modifiable factors that influence this association. This study investigates whether the association between maternal sensitivity and infant cognitive development in the first year of life is accounted for by other factors, such as breastfeeding, maternal depressive symptoms, maternal alcohol use, infant birth weight or demographic covariates. METHODS: Using data from the Early Childhood Longitudinal Study-Birth (ECLS-B) Cohort, a nationally representative sample of U.S. born children, multi-variable regression analyses was used to examine whether breastfeeding, maternal depressive symptoms and alcohol use were associated with maternal sensitivity, as measured by the Nursing Child Assessment Teaching Scale (NCATS), and with infant cognitive development, as measured by the Bayley Scales of Infant Development, Short Form, Research Edition, after controlling for demographic covariates (infant sex, maternal age, education, race/ethnicity, income, parity, family structure) and infant birth weight. RESULTS: Breastfeeding, depressive symptoms and alcohol use were not associated with maternal sensitivity scores after controlling for demographic covariates and infant birth weight. However, breastfeeding (ß = .079, p < .001), depressive symptoms (ß = -.035, p < .05), and maternal sensitivity (ß = .175, p < .001) were each significantly associated with infant cognitive development scores, even after controlling for demographic covariates and birthweight (R2 = .053, p < .001). The association between maternal sensitivity and infant cognitive development did not attenuate after adjusting for breastfeeding. Instead, both sensitivity and breastfeeding independently contributed to higher infant cognitive development scores. CONCLUSION: Maternal sensitivity and breastfeeding are separate means to advancing infant cognitive development. This study is significant because it is the first to examine breastfeeding, maternal depressive symptoms and alcohol use together, upon the association between maternal sensitivity and infant cognitive development, after adjusting for demographic covariates and infant birthweight. Maternal sensitivity, a measurable quality, advances infants' cognitive development. Moreover, sensitivity and breastfeeding had independent effects upon cognitive development after controlling for multiple fixed and modifiable covariates. Understanding factors impacting the association between sensitivity and infant cognitive development provide avenues for developing more effective parenting interventions.