The invisible frontier. A multiple species model for the origin of behavioral modernity

Two contradictory theories of human cognitive evolution have been developed to model how, when, and among what hominid groups behavioral modernity emerged. The first model, which has long been the dominant paradigm, links these behavioral innovations to a cultural “revolution” by anatomically modern humans in Europe at around 40,000 years ago, coinciding with the first arrival of our species in this region.^1–4 According to this model, the sudden and explosive character of this change is demonstrated by the appearance in the archeological record of previously unseen carvings, personal ornaments, musical instruments, depictions on cave walls, and new stone and bone technology. A variant of this model sees behavioral modernity resulting from a rapid biological change, a brain mutation producing no apparent change in skull anatomy, which occurred in Europe or, more probably, in Africa at ca. 50,000 years ago.⁵⁶.     

Implications of the behavioural immune system for social behaviour and human health in the modern world

The ‘behavioural immune system’ is composed of mechanisms that evolved as a means of facilitating behaviours that minimized infection risk and enhanced fitness. Recent empirical research on human populations suggests that these mechanisms have unique consequences for many aspects of human sociality—including sexual attitudes, gregariousness, xenophobia, conformity to majority opinion and conservative sociopolitical attitudes. Throughout much of human evolutionary history, these consequences may have had beneficial health implications; but health implications in modern human societies remain unclear. This article summarizes pertinent ways in which modern human societies are similar to and different from the ecologies within which the behavioural immune system evolved. By attending to these similarities and differences, we identify a set of plausible implications—both positive and negative—that the behavioural immune system may have on health outcomes in contemporary human contexts. We discuss both individual-level infection risk and population-level epidemiological outcomes. We also discuss a variety of additional implications, including compliance with public health policies, the adoption of novel therapeutic interventions and actual immunological functioning. Research on the behavioural immune system, and its implications in contemporary human societies, can provide unique insights into relationships between fitness, sociality and health.     

The revolution that wasn't: a new interpretation of the origin of modern human behavior

Proponents of the model known as the "human revolution" claim that modern human behaviors arose suddenly, and nearly simultaneously, throughout the Old World ca. 40-50 ka. This fundamental behavioral shift is purported to signal a cognitive advance, a possible reorganization of the brain, and the origin of language. Because the earliest modern human fossils, Homo sapiens sensu stricto, are found in Africa and the adjacent region of the Levant at >100 ka, the "human revolution" model creates a time lag between the appearance of anatomical modernity and perceived behavioral modernity, and creates the impression that the earliest modern Africans were behaviorally primitive. This view of events stems from a profound Eurocentric bias and a failure to appreciate the depth and breadth of the African archaeological record. In fact, many of the components of the "human revolution" claimed to appear at 40-50 ka are found in the African Middle Stone Age tens of thousands of years earlier. These features include blade and microlithic technology, bone tools, increased geographic range, specialized hunting, the use of aquatic resources, long distance trade, systematic processing and use of pigment, and art and decoration. These items do not occur suddenly together as predicted by the "human revolution" model, but at sites that are widely separated in space and time. This suggests a gradual assembling of the package of modern human behaviors in Africa, and its later export to other regions of the Old World. The African Middle and early Late Pleistocene hominid fossil record is fairly continuous and in it can be recognized a number of probably distinct species that provide plausible ancestors for H. sapiens. The appearance of Middle Stone Age technology and the first signs of modern behavior coincide with the appearance of fossils that have been attributed to H. helmei, suggesting the behavior of H. helmei is distinct from that of earlier hominid species and quite similar to that of modern people. If on anatomical and behavioral grounds H. helmei is sunk into H. sapiens, the origin of our species is linked with the appearance of Middle Stone Age technology at 250-300 ka.     

Modern human origins: progress and prospects

The question of the mode of origin of modern humans (Homo sapiens) has dominated palaeoanthropological debate over the last decade. This review discusses the main models proposed to explain modern human origins, and examines relevant fossil evidence from Eurasia, Africa and Australasia. Archaeological and genetic data are also discussed, as well as problems with the concept of 'modernity' itself. It is concluded that a recent African origin can be supported for H. sapiens, morphologically, behaviourally and genetically, but that more evidence will be needed, both from Africa and elsewhere, before an absolute African origin for our species and its behavioural characteristics can be established and explained.     

The revolution that didn't arrive: A review of Pleistocene Sahul

There is a "package" of cultural innovations that are claimed to reflect modern human behaviour. The introduction of the "package" has been associated with the Middle-to-Upper Palaeolithic transition and the appearance in Europe of modern humans. It has been proposed that modern humans spread from Africa with the "package" and colonised not only Europe but also southern Asia and Australia (McBrearty and Brooks, 2000; Mellars, 2006a). In order to evaluate this proposal, we explore the late Pleistocene archaeological record of Sahul, the combined landmass of Australia and Papua New Guinea, for indications of these cultural innovations at the earliest sites. It was found that following initial occupation of the continent by anatomically and behaviourally modern humans, the components were gradually assembled over a 30,000-year period. We discount the idea that the "package" was lost en route to Sahul and assess the possibility that the "package" was not integrated within the material culture of the initial colonising groups because they may not have been part of a rapid colonisation process from Africa. As the cultural innovations appear at different times and locations within Sahul, the proposed "package" of archaeologically visible traits cannot be used to establish modern human behaviour. Whilst the potential causal role of increasing population densities/pressure in the appearance of the "package" of modern human behaviour in the archaeological record is acknowledged, it is not seen as the sole explanation because the individual components of the "package" appear at sites that are widely separated in space and time.     

Opiate versus psychostimulant addiction: the differences do matter

The publication of the psychomotor stimulant theory of addiction in 1987 and the finding that addictive drugs increase dopamine concentrations in the rat mesolimbic system in 1988 have led to a predominance of psychobiological theories that consider addiction to opiates and addiction to psychostimulants as essentially identical phenomena. Indeed, current theories of addiction - hedonic allostasis, incentive sensitization, aberrant learning and frontostriatal dysfunction - all argue for a unitary account of drug addiction. This view is challenged by behavioural, cognitive and neurobiological findings in laboratory animals and humans. Here, we argue that opiate addiction and psychostimulant addiction are behaviourally and neurobiologically distinct and that the differences have important implications for addiction treatment, addiction theories and future research.     

Evolution,revolution or saltation scenario for the emergence of modern cultures?

Crucial questions in the debate on the origin of quintessential human behaviours are whether modern cognition and associated innovations are unique to our species and whether they emerged abruptly, gradually or as the result of a discontinuous process. Three scenarios have been proposed to account for the origin of cultural modernity. The first argues that modern cognition is unique to our species and the consequence of a genetic mutation that took place approximately 50 ka in Africa among already evolved anatomically modern humans. The second posits that cultural modernity emerged gradually in Africa starting at least 200 ka in concert with the origin of our species on that continent. The third states that innovations indicative of modern cognition are not restricted to our species and appear and disappear in Africa and Eurasia between 200 and 40 ka before becoming fully consolidated. We evaluate these scenarios in the light of new evidence from Africa, Asia and Europe and explore the mechanisms that may have led to modern cultures. Such reflections will demonstrate the need for further inquiry into the relationship between climate and demographic/cultural change in order to better understand the mechanisms of cultural transmission at work in Neanderthals and early Homo sapiens populations.     

Innovation and technological knowledge in the Upper Paleolithic of Northern Eurasia

The technology of modern humans is unique in the animal kingdom with respect to its complexity and capacity for innovation. Evidence of technological complexity and creativity in the archeological record is broadly coincident with and presumably related to traces of creativity in art, music, ritual, and other forms of symbolism. The pattern of modern human technology is part of a larger package of behavior (sometimes referred to as “behavioral modernity”) that emerges with the appearance of industries in Eurasia classified as Upper Paleolithic, but has deeper roots in the African Middle Stone Age. 1 - 5 .     

The impact of Cenozoic cooling on assemblage diversity in planktonic foraminifera

The Cenozoic planktonic foraminifera (PF) (calcareous zooplankton) have arguably the most detailed fossil record of any group. The quality of this record allows models of environmental controls on macroecology, developed for Recent assemblages, to be tested on intervals with profoundly different climatic conditions. These analyses shed light on the role of long-term global cooling in establishing the modern latitudinal diversity gradient (LDG)—one of the most powerful generalizations in biogeography and macroecology. Here, we test the transferability of environment-diversity models developed for modern PF assemblages to the Eocene epoch (approx. 56–34 Ma), a time of pronounced global warmth. Environmental variables from global climate models are combined with Recent environment–diversity models to predict Eocene richness gradients, which are then compared with observed patterns. The results indicate the modern LDG—lower richness towards the poles—developed through the Eocene. Three possible causes are suggested for the mismatch between statistical model predictions and data in the Early Eocene: the environmental estimates are inaccurate, the statistical model misses a relevant variable, or the intercorrelations among facets of diversity—e.g. richness, evenness, functional diversity—have changed over geological time. By the Late Eocene, environment–diversity relationships were much more similar to those found today.     

Physiological tolerance of Drosophila simulans to dark environment: A comparison with D. melanogaster

According to ecological and behavioural studies, Drosophila simulans is considered to be less tolerant of darkness than its sibling species D. melanogaster which is well adapted both behaviourally and physiologically to darkness. The relationships between physiological and behavioural adaptations have been analysed by studying the developmental and the reproductive capacities of D. simulans submitted to various light regimes (LL, LD 12:12, DD). This species has a lower reproductive capacity than D. melanogaster but failed to react to light treatment. In particular, D. simulans showed no effect of darkness on either fertilization or ovarian function. The lack of differences between D. melanogaster and D. simulans as regards their physiological capacities in relation to light regime suggests that the selective pressures of light may act at different levels of regulation.     

Resonant neurons and bushcricket behaviour

The resonant properties of the intrinsic dynamics of single neurons could play a direct role in behaviour. One plausible role is in the recognition of temporal patterns, such as that seen in the auditory communication systems of Orthoptera. Recent behavioural data from bushcrickets suggests that this behaviour has interesting resonance properties, but the underlying mechanism is unknown. Here we show that a very simple and general model for neural resonance could directly account for the different behavioural responses of bushcrickets to different song patterns.     

Rationality, biology and optimality*

A historical theory of rational norms claims that, if we are supposed to think rationally, this is because it is biologically normal for us to do so. The historical theorist is committed to the view that we are supposed to think rationally only if, in the past, adult humans sometimes thought rationally. I consider whether there is any plausible model of rational norms that can be adopted by the historical theorist that is compatible with the claim that adult human beings are subject to rational norms, given certain plausible empirical assumptions about our history and capabilities. I suggest that there is one such model: this model centres on the idea that a procedure is rational if it has been endorsed (or at least not rejected) by mechanisms that have the function to ensure that the subject learns to reason in a way that approaches a certain kind of optimality. This revised version was published online in July 2006 with corrections to the Cover Date.     

From small holes to grand narratives: the impact of taphonomy and sample size on the modernity debate in Australia and New Guinea

Our knowledge of early Australasian societies has significantly expanded in recent decades with more than 220 Pleistocene sites reported from a range of environmental zones and depositional contexts. The uniqueness of this dataset has played an increasingly important role in global debates about the origins and expression of complex behaviour among early modern human populations. Nevertheless, discussions of Pleistocene behaviour and cultural innovation are yet to adequately consider the effects of taphonomy and archaeological sampling on the nature and representativeness of the record. Here, we investigate the effects of preservation and sampling on the archaeological record of Sahul, and explore the implications for understanding early cultural diversity and complexity. We find no evidence to support the view that Pleistocene populations of Sahul lacked cognitive modernity or cultural complexity. Instead, we argue that differences in the nature of early modern human populations across the globe were more likely the consequence of differences in population size and density, interaction and historical contingency.     

Ecological effects of pharmaceuticals in aquatic systems—impacts through behavioural alterations

The study of animal behaviour is important for both ecology and ecotoxicology, yet research in these two fields is currently developing independently. Here, we synthesize the available knowledge on drug-induced behavioural alterations in fish, discuss potential ecological consequences and report results from an experiment in which we quantify both uptake and behavioural impact of a psychiatric drug on a predatory fish (Perca fluviatilis) and its invertebrate prey (Coenagrion hastulatum). We show that perch became more active while damselfly behaviour was unaffected, illustrating that behavioural effects of pharmaceuticals can differ between species. Furthermore, we demonstrate that prey consumption can be an important exposure route as on average 46% of the pharmaceutical in ingested prey accumulated in the predator. This suggests that investigations of exposure through bioconcentration, where trophic interactions and subsequent bioaccumulation of exposed individuals are ignored, underestimate exposure. Wildlife may therefore be exposed to higher levels of behaviourally altering pharmaceuticals than predictions based on commonly used exposure assays and pharmaceutical concentrations found in environmental monitoring programmes.     

The expert Neandertal mind

Cognitive neuropsychology, cognitive anthropology, and cognitive archaeology are combined to yield a picture of Neandertal cognition in which expert performance via long-term working memory is the centerpiece of problem solving. This component of Neandertal cognition appears to have been modern in scope. However, Neandertals' working memory capacity, which is the ability to hold a variety of information in active attention, may not have been as large as that of modern humans. This characteristic helps us understand features of the archaeological record, such as the rarity of innovation, and allows us to make empirically based speculations about Neandertal personality.     

The earliest evidence of holometabolan insect pupation in conifer wood

Background

The pre-Jurassic record of terrestrial wood borings is poorly resolved, despite body fossil evidence of insect diversification among xylophilic clades starting in the late Paleozoic. Detailed analysis of borings in petrified wood provides direct evidence of wood utilization by invertebrate animals, which typically comprises feeding behaviors.

Methodology/Principal Findings

We describe a U-shaped boring in petrified wood from the Late Triassic Chinle Formation of southern Utah that demonstrates a strong linkage between insect ontogeny and conifer wood resources. Xylokrypta durossi new ichnogenus and ichnospecies is a large excavation in wood that is backfilled with partially digested xylem, creating a secluded chamber. The tracemaker exited the chamber by way of a small vertical shaft. This sequence of behaviors is most consistent with the entrance of a larva followed by pupal quiescence and adult emergence — hallmarks of holometabolous insect ontogeny. Among the known body fossil record of Triassic insects, cupedid beetles (Coleoptera: Archostemata) are deemed the most plausible tracemakers of Xylokrypta, based on their body size and modern xylobiotic lifestyle.

Conclusions/Significance

This oldest record of pupation in fossil wood provides an alternative interpretation to borings once regarded as evidence for Triassic bees. Instead Xylokrypta suggests that early archostematan beetles were leaders in exploiting wood substrates well before modern clades of xylophages arose in the late Mesozoic.     

中国古人类颅容量的推算方法比较

古人类的体质特征和现代人不同,依据现代人头骨测量数据计算出来的公式往往不适于古人类颅容量的推算。获取古人类颅容量最准确的方法是复原出其内部的颅内模;然而,由于颅内模的复原工艺复杂,加上古人类头骨化石数量稀少且多数残破,如何准确地推算其颅容量,成为古人学者研究的难点问题之一。本文通过对中国境内发现的不同演化阶段的古人类颅容量推算方法的对比和验证,试图找出推算古人类颅容量的最适合的公式法。研究结果显示：1）早期现代人解剖特征同现代人基本接近,依据现代人头骨推算出来的回归方程可以用来推算其颅容量;2）直立人头骨厚重、脑颅低矮,体质特征不同于现代人,其颅容量的推算不能使用现代人公式法。依据本文中国直立人头骨测量数据推导出来的回程方程（C=-1301.944+60606L+0.718b+9.936h）适合其颅容量的推算。采用此直立人公式法,推算出蓝田直立人的颅容量为918 mL;3）古老型智人的体质特征位于直立人和现代人之间,对其颅容量的推算不能一概而论：体质特征接近直立人的,如大荔人、华龙洞6号,可采用直立人公式法;体质特征接近早期现代人的,如许昌1号,可采用现代人公式法;体质特征位于直立人和早期现代人中间位置的,如马坝人、金牛山人,其颅容量约等于采用现代人公式法和采用直立人公式法获得的颅容量的平均值。     

Middle eastern origin model forHomo sapiens (Moderns & Neanderthals), language and modern behaviour

A new model may resolve the problem of when and where did appear anatomically modern humans. According to this model, Neanderthals were probably neither our ancestor nor different species.Homo sapiens appeared probably in the Middle East, approximately 150 ka ago and differentiated to anatomically modern humans and Neanderthals because of the genetic programme. The fossils older than 150 ka are probably not Neanderthal such as Zuttiyeh and Biache-Saint-Vaast specimens. Cultural capacities of Neanderthals were probably equivalent to Moderns. Most of pre-Homo sapiens populations may be extinct without replacement byHomo sapiens. Language and modern behaviour should have arisen with our own species.     

Animal culture research should include avian nest construction

Material culture—that is, group-shared and socially learned object-related behaviour(s)—is a widespread and diverse phenomenon in humans. For decades, researchers have sought to confirm the existence of material culture in non-human animals; however, the main study systems of interest—namely, tool making and/or using non-human primates and corvids—cannot provide such confirmatory evidence: because long-standing ethical and logistical constraints handicap the collection of necessary experimental data. Synthesizing evidence across decades and disciplines, here, I present a novel framework for (mechanistic, developmental, behavioural, and comparative) study on animal material culture: avian nest construction.