The ‘mosaic habitat’ concept in human evolution: past and present

The habitats preferred by hominins and other species are an important theme in palaeoanthropology, and the ‘mosaic habitat’ (also referred to as habitat heterogeneity) has been a central concept in this regard for the last four decades. Here we explore the development of this concept – loosely defined as a range of different habitat types, such as woodlands, riverine forest and savannah within a limited spatial area– in studies of human evolution in the last sixty years or so. We outline the key developments that took place before and around the time when the term ‘mosaic’ came to wider palaeoanthropological attention. To achieve this we used an analysis of the published literature, a study of illustrations of hominin evolution from 1925 onwards and an email survey of senior researchers in palaeoanthropology and related fields. We found that the term mosaic starts to be applied in palaeoanthropological thinking during the 1970’s due to the work of a number of researchers, including Karl Butzer and Glynn Isaac , with the earliest usage we have found of ‘mosaic’ in specific reference to hominin habitats being by Adriaan Kortlandt (1972). While we observe a steady increase in the numbers of publications reporting mosaic palaeohabitats, in keeping with the growing interest and specialisation in various methods of palaeoenvironmental reconstruction, we also note that there is a lack of critical studies that define this habitat, or examine the temporal and spatial scales associated with it. The general consensus within the field is that the concept now requires more detailed definition and study to evaluate its role in human evolution

Effects of divorce on Dutch boys' and girls' externalizing behavior in Gene x Environment perspective: Diathesis stress or differential susceptibility in the Dutch Tracking Adolescents' Individual Lives Survey study?

The effects of divorce on children's behavioral development have proven to be quite varied across studies, and most developmental and family scholars today appreciate the great heterogeneity in divorce effects. Thus, this inquiry sought to determine whether select dopaminergic genes previously associated with externalizing behavior and/or found to moderate diverse environmental effects (dopamine receptors D2 and D4, catechol-O-methyltransferase) might moderate divorce effects on adolescent self-reported externalizing problems; and, if so, whether evidence of gene environment (G x E) interaction would prove consistent with diathesis stress or differential-susceptibility models of environmental action. Data from the first and third wave of the Dutch Tracking Adolescents' Individual Lives Survey (n = 1,134) revealed some evidence of G x E interaction reflecting diathesis stress but not differential susceptibility. It is intriguing that some evidence pointed to "vantage sensitivity," which are benefits accruing to those with a specific genotype when their parents remained together, the exact opposite of diathesis stress. The limits of this work are considered, especially with regard to the conditions for testing differential susceptibility, and future directions are outlined

The nature (and nurture?) of plasticity in early human development

The effect of early experience is a long-standing concern in developmental psychology. Gaining further insight into the nature of human plasticity is central to efforts to prevent problems in development from arising and promote positive functioning. Evolutionary reasoning suggests that children should vary in their susceptibility to environmental influences, including parenting. Evidence indicates that rather than some children, such as those with negatively emotional temperaments or certain genotypes, being simply more vulnerable to the adverse effects of negative experiences, as commonly assumed, they may actually be more susceptible to both positive and negative experiences. In addition to raising questions about the nature of plasticity in human development, this article highlights unknowns regarding the role of nature and nurture in shaping individual differences in plasticity, including whether recent research linking maternal stress during pregnancy with child behavior problems illuminates a process whereby fetal programming shapes the child's susceptibility to postnatal environmental influences. Throughout this article, we raise concern about the potentially distorting influence that psychology's disproportionate focus on the adverse effect of negative experiences on developmental problems has on our understanding of human plasticity, and we propose that researchers should pay more attention to the positive side of the plasticity equation