The Routledge Handbook of Mechanisms and Mechanical Philosophy is an outstanding reference source to the key topics, problems, and debates in this exciting subject and is the first collection of its kind. Comprising over thirty chapters by a team of international contributors, the Handbook is divided into four Parts: Historical perspectives on mechanisms The nature of mechanisms Mechanisms and the philosophy of science Disciplinary perspectives on mechanisms. Within these Parts central topics and problems are examined, (...) including the rise of mechanical philosophy in the seventeenth century; what mechanisms are made of and how they are organized; mechanisms and laws and regularities; how mechanisms are discovered and explained; dynamical systems theory; and disciplinary perspectives from physics, chemistry, biology, biomedicine, ecology, neuroscience, and the social sciences. Essential reading for students and researchers in philosophy of science, the Handbook will also be of interest to those in related fields, such as metaphysics, philosophy of psychology, and history of science. (shrink)

The majority of the commentaries focused on excessive crying and colic and included two major themes: the consideration of proximate physiological mechanisms, and challenges to my interpretation of the signal functions of early infant crying amount. I initially concluded that none of the competing signaling hypotheses enjoyed strong support, but I nevertheless favored the signaling vigor hypothesis above the signaling need and manipulation hypotheses. Consideration of the neurobiological causation of the n-shaped crying curve and further evidence and argumentation concerning (...) the potential signal functions, however, do not allow for the elevation of any one of these hypotheses above the others, and it remains the case that none are strongly supported. Taken together, however, the target article and commentary do provide a solid foundation for further research. In the target article, I also proposed a model of how infant cry acoustics can influence patterns of care and abuse. Commentary has enriched this model by including the consideration of developmental changes in cry acoustics across early infancy, and by further integrating the cry signal with other modalities of communication and with later development. I trust that the foregoing will show that the joint pursuit of the proximate mechanisms and the potential signal functions of early infant cry amount and cry acoustics should prove fruitful. Before embarking on my reevaluation, however, I begin this response by addressing the issue of consciousness in evolutionary accounts of signaling. (shrink)

An alteration in the developmental mechanisms that regulate telencephalic patterning or pallial growth may have led to an enlargement of the dorsal pallium during evolution, and to the origin of isocortex. Developmental mechanisms that may have produced a pallial enlargement, and the parallelism of this event with the enlargement of the dorsal thalamus during evolution are discussed.

Retinoids are low molecular weight, lipophilic derivatives of vitamin A which have a profound effect upon the development of a diverse array of animals. Here, I review these effects on Invertebrates: a colonial hydroid, a colonial ascidian, and Vertebrates: the regenerating amphibian limb, the developing chick limb bud, the regenerating amphibian tail, the anteroposterior axis of the early embryo, the developing chick embryo skin. There is a striking uniformity of effect of retinoids on pattern formation when applied to these diverse (...) organisms. The majority react by being posteriorized in their development, although additional effects can also be seen. Several hypotheses which can explain these results are discussed along with the deduction that they lead to: retinoids may be components of a universal developmental mechanism or they may simply act in a similar way to alter a universal developmental mechanism. In either case the experimental analysis of retinoid effects on development has important implications for the evolution of developmental mechanisms. (shrink)

Overview The evolution of multicellularity raises questions regarding genomic and developmental commonalities and discordances, selective advantages and disadvantages, physical determinants of development, and the origins of morphological novelties. It also represents a change in the definition of individuality, because a new organism emerges from interactions among single cells. This volume considers these and other questions, with contributions that explore the origins and consequences of the evolution of multicellularity, addressing a range of topics, organisms, and experimental protocols. Each section focuses (...) on selected topics or particular lineages that present a significant insight or challenge. The contributors consider the fossil record of the paleontological circumstances in which animal multicellularity evolved; cooptation, recurrent patterns, modularity, and plausible pathways for multicellular evolution in plants; theoretical approaches to the amoebozoa and fungi (cellular slime molds having long provided a robust model system for exploring the evolution of multicellularity), plants, and animals; genomic toolkits of metazoan multicellularity; and philosophical aspects of the meaning of individuality in light of multicellular evolution. Contributors Maja Adamska, Argyris Arnellos, Juan A. Arias, Eugenio Azpeitia, Mariana Benítez, Adriano Bonforti, John Tyler Bonner, Peter L. Conlin, A. Keith Dunker, Salva Duran-Nebreda, Ana E. Escalante, Valeria Hernández-Hernández, Kunihiko Kaneko, Andrew H. Knoll, Stephan G. König, Daniel J. G. Lahr, Ottoline Leyser, Alan C. Love, Raul Montañez, Emilio Mora van Cauwelaert, Alvaro Moreno, Vidyanand Nanjundiah, Aurora M. Nedelcu, Stuart A. Newman, Karl J. Niklas, William C. Ratcliff, Iñaki Ruiz-Trillo, Ricard Solé . (shrink)

Although the authors' ingenuity in identifying criteria for innovation for field studies is appealing, most field studies will lack adequate data. Additionally, their definition does not clearly distinguish innovation from individual learning and is vague about cognitive mechanisms involved. We suggest that developmental data are essential to identifying the causes and consequences of learning new behaviors.

The shapes of neurons and glial cells dictate many important aspects of their functions. In olfactory systems, certain architectural features are characteristics of these two cell types across a wide variety of species. The accumulated evidence suggests that these common features may play fundamental roles in olfactoryinformation processing. For instance, the primary olfactory neuropil in most vertebrate and invertebrate olfactory systems is organized into discrete modules called glomeruli. Inside each glomerulus, sensory axons and CNS neurons branch and synapse in patterns (...) that are repeated across species. In many species, moreover, the glomeruli are enveloped by a thin and ordered layer of glial processes. Theglomerular arrangement reflects the processing of odor information in modules that encode the discrete molecular attributes of odorant stimuli being processed. Recent studies of the mechanisms that guide the development of olfactory neurons and glial cells have revealed complex reciprocal interactions between these two cell types, which may be necessary for the establishment of modular compartments. Collectively, the findings reviewed here suggest that specialized cellular architecture plays key functional roles in the detection, analysis, and discrimination of odors at early steps in olfactory processing. (shrink)

Efforts from diverse disciplines, including evolutionary studies and biomechanical experiments, have yielded new insights into the genetic, signaling, and mechanical control of tooth formation and functions. Evidence from fossils and non‐model organisms has revealed that a common set of genes underlie tooth‐forming potential of epithelia, and changes in signaling environments subsequently result in specialized dentitions, maintenance of dental stem cells, and other phenotypic adaptations. In addition to chemical signaling, tissue forces generated through epithelial contraction, differential growth, and skeletal constraints act (...) in parallel to shape the tooth throughout development. Here recent advances in understanding dental development from these studies are reviewed and important gaps that can be filled through continued application of evolutionary and biomechanical approaches are discussed. (shrink)

U poslednjih nekoliko dekada vise studija posvecenih percepciji novorodjencadi je ukazalo na to da cak i tek rodjena deca jesu osetljiva na nacin na koji se objekti pokrecu i na prirodu njihove interakcije. Da bi objasnili ranu pojavu ovakve osetljivosti na kauzalne odnose neki psiholozi zastupaju stanoviste da postoji urodjeno znanje vezano za objekte. Cilj ovog rada je da preispita ovakva nativisticka objasnjenja tako sto ce da preispita da li ova objasnjenja ispunjavaju uslove koji svaki mehanicisticki model mora da ispuni (...) da bi bio uspesan. Craver je razvio nekoliko takvih kriterijuma kao i distinkciju izmedju odgovarajuceg mehanicistickog modela i mehanicisticke skice. Moj cilj je da pokazem da nativisticki modeli razvoja ne ispunjavaju ove kriterijume. Prvo, ti modeli samo delimicno a ne u potpunosti opisuju fenomen. Drugo, nativisti ukljucuju u opis fenomena odredjenu teoriju percepcije koja zahteva dodatnu empirijsku evidenciju i ne moze biti bezrezervno prihvacena kao tacna. Ja cu takodje argumentovati da je urodjeno znanje dobar kandidat za ono sto Craver naziva?praznim terminom? i da ce najverovatnije biti napusten. Novija istrazivanja koja su ispitivala intersenzornu percepciju ukazuju na to da je mehanizam odgovoran za rano opazanje kauzalnih odnosa najverovatnije deo nase najosnovnije fiziologije i da kao takav ne ukljucuje sofisticirane kognitivne strukture niti urodjeno znanje. Takodje, ova istrazivanja ukazuju na to da je standardna debata izmedju nativista i empirista pogresno postavljena i da bi je trebalo napustiti. (shrink)

Biofeedback mechanisms (a) between individuals, (b) between the individual and the society structures which shape individual cognitions, and (c) within the individual genetic biochemical circulation, may explain the diversity of trustworthiness potential and the option of mutual trust for every individual in any given society.

Lewis describes the developmental core of dynamic systems theory. I offer recent data from developmental neuroscience on the sequential experience-dependent maturation of components of the limbic system over the stages of infancy. Increasing interconnectivity within the vertically integrated limbic system allows for more complex appraisals of emotional value. The earliest organization of limbic structures has an enduring impact on all later emotional processing.

Evolutionary developmental biology (evo-devo) is considered a ‘mechanistic science,’ in that it causally explains morphological evolution in terms of changes in developmental mechanisms. Evo-devo is also an interdisciplinary and integrative approach, as its explanations use contributions from many fields and pertain to different levels of organismal organization. Philosophical accounts of mechanistic explanation are currently highly prominent, and have been particularly able to capture the integrative nature of multifield and multilevel explanations. However, I argue that evo-devo demonstrates the (...) need for a broadened philosophical conception of mechanisms and mechanistic explanation. Mechanistic explanation (in terms of the qualitative interactions of the structural parts of a whole) has been developed as an alternative to the traditional idea of explanation as derivation from laws or quantitative principles. Against the picture promoted by Carl Craver, that mathematical models describe but usually do not explain, my discussion of cases from the strand of evo-devo which is concerned with developmental processes points to qualitative phenomena where quantitative mathematical models are an indispensable part of the explanation. While philosophical accounts have focused on the actual organization and operation of mechanisms, properties of developmental mechanisms that are about how a mechanism reacts to modifications are of major evolutionary significance, including robustness, phenotypic plasticity, and modularity. A philosophical conception of mechanisms is needed that takes into account quantitative changes, transient entities and the generation of novel types of entities, feedback loops and complex interaction networks, emergent properties, and, in particular, functional-dynamical aspects of mechanisms, including functional (as opposed to structural) organization and distributed, system-wide phenomena. I conclude with general remarks on philosophical accounts of explanation. (shrink)

People recognize faces of their own race more accurately than faces of other races. The “contact” hypothesis suggests that this “other‐race effect” occurs as a result of the greater experience we have with own‐ versus other‐race faces. The computational mechanisms that may underlie different versions of the contact hypothesis were explored in this study. We replicated the other‐race effect with human participants and evaluated four classes of computational face recognition algorithms for the presence of an other‐race effect. Consistent with (...) the predictions of a developmental contact hypothesis, “experience‐based models” demonstrated an other‐race effect only when the representational system was developed through experience that warped the perceptual space in a way that was sensitive to the overall structure of the model's experience with faces of different races. When the model's representation relied on a feature set optimized to encode the information in the learned faces, experience‐based algorithms recognized minority‐race faces more accurately than majority‐race faces. The results suggest a developmental learning process that warps the perceptual space to enhance the encoding of distinctions relevant for own‐race faces. This feature space limits the quality of face representations for other‐race faces. (shrink)

A vivid and bizarre dream conjures up a myriad of novel mental images. The same exact images can be created volitionally when awake. The neurological mechanisms of these two processes are different. The voluntary combination of mental objects is mediated by the lateral prefrontal cortex and patients with damage to the LPFC often lose this ability. Conversely, the combination of mental objects into novel images during dreaming does not depend on the LPFC; LPFC is inactive during sleep and patients (...) whose LPFC is damaged do not notice a change in their dreams. Neither colloquial English nor scientific jargon has an established way to report on the origin of a conjured up mental image; the term “imagination” is regularly used to describe any experience generated internally whether voluntarily or involuntarily. Failing to distinguish be­tween voluntary and involuntary imagination leads to confusion in developmental psy­chology, neurolinguistics, and paleoanthropology. A comprehensive understanding of the distinction between voluntary and involuntary imagination will help develop better thera­py for children with language delay, contribute to a clearer understanding of the unique­ness of human language, and enable a more productive discussion of the evolutionary ori­gin of human language. (shrink)

Conrad Hal Waddington was a British developmental biologist who mainly worked in Cambridge and Edinburgh, but spent the late 1930s with Morgan in California learning about Drosophila. He was the first person to realize that development depended on the then unknown activities of genes, and he needed an appropriate model organism. His major experimental contributions were to show how mutation analysis could be used to investigate developmental mechanisms in Drosophila, and to explore how developmental mutation could (...) drive evolution, his other deep interest. Waddington was, however, predominantly a thinker, and set out to provide a coherent framework for understanding the genetic bases of embryogenesis and evolution, developing his ideas in many books. Perhaps his best-known concept is the epigenetic landscape: here a ball rolls down a complex valley, making path choices. The rolling ball represents a cell’s development over time, while the topography represents the changing regulatory environment that controls these choices. In its later forms, the role of each feature in the landscape was controlled by the effects of sets of interacting genes, an idea underpinning contemporary approaches to systems biology. Waddington was the first developmental geneticist and probably the most important developmental biologist of the pre-molecular age. (shrink)

Lindquist et al.'s meta-analysis focuses on adult humans; the authors' emotion model might be strengthened by considering research on infants and animals, highlighting the importance of the limbic system. Reliance on the James–Lange theory is questionable; emotions typically occur instantaneously, with dubious dependence on bodily feedback for affect. Stronger evidence for localization might be obtained using more precise emotion terms and alterative localization methods.

Many biologists assume, as Darwin did, that natural selection acts mainly on late embryonic or postnatal development. This view is consistent with von Baer's observations of morphological divergence at late stages. It is also suggested by the conserved morphology and common molecular genetic mechanisms of pattern formation seen in embryos. I argue here, however, that differences in adult morphology may be generated at a variety of stages. Natural selection may have a major action on developmental mechanisms during (...) the organogenetic period, because this is when many adult traits are specified. Evolutionary changes in these early developmental mechanisms probably include subtle shifts in the timing of gene expression. Changes of this kind have little or no gross effect on the anatomy of the embryo; they are only phenotypically expressed, or readily detected, when amplified at later stages. The phylotypic stage, the developmental hourglass, modularity, and von Baerian divergence are reassessed in terms of these arguments. BioEssays 21:604–613, 1999. © 1999 John Wiley & Sons, Inc. (shrink)

The concept of scaffolding has wide resonance in several scientific fields. Here we attempt to adopt it for the study of development. In this perspective, the embryo is conceived as an integral whole, comprised of several hierarchical modules as in a recurrent circularity of emerging patterns. Within the developmental hierarchy, each module yields an inter-level relationship that makes it possible for the scaffolding to mediate the production of selectable variations. A wide range of genetic, cellular and morphological mechanisms (...) allows the scaffolding to integrate these modular variations into a functionally coordinate unit. A genetic scaffolding accounts for the inherited invariance of pattern formation during the embryo’s growth. At higher level, cells behave as agents endowed with the capacity to interpret any scaffolding variation as signs. The full hierarchy of a multi-level scaffolding is eventually attained when the embryo acquires the capacity to impose a number of developmental constraints on its constituting parts in a top-down direction. The acquisition of this capacity allows a semiotic threshold to emerge between the living cellular world and the underlying non-living molecular world. As this boundary is gradually defined during development, cells enter into new functional relationships, while, at the same time, are relieved from their physical determinism. The resulting constraints can thus become the driving forces that upgrade embryonic scaffolding from the simple molecular signalling to the complexity of sign recognition proper of a cellular community. In this semiotic perspective, the apparent goal directness of any developmental strategy should no longer be accounted for by a predetermined genetic program, but by the gradual definition of the relationships selected amongst the ones historically explored. (shrink)

The nature/nurture debate is not dead. Dichotomous views of development still underlie many fundamental debates in the biological and social sciences. Developmental systems theory offers a new conceptual framework with which to resolve such debates. DST views ontogeny as contingent cycles of interaction among a varied set of developmental resources, no one of which controls the process. These factors include DNA, cellular and organismic structure, and social and ecological interactions. DST has excited interest from a wide range of (...) researchers, from molecular biologists to anthropologists, because of its ability to integrate evolutionary theory and other disciplines without falling into traditional oppositions. The book provides historical background to DST, recent theoretical findings on the mechanisms of heredity, applications of the DST framework to behavioral development, implications of DST for the philosophy of biology, and critical reactions to DST. (shrink)

Fisher, Jin, and Scott push a central assumption of syntactic bootstrapping: that learners have a universal bias to map each noun in a sentence onto a participant role (i.e., argument of the verb). They propose two enrichments: First, that children use both semantic and syntactic information in representing nouns that accompany a verb; second, that children expect continuity across a discourse. They provide evidence for both learning mechanisms among young children, further spelling out the precise mechanisms underlying syntactic (...) bootstrapping. (shrink)

Late lung development comprises the formation of the terminal sac followed by the subdivision of the terminal sac by septa into alveoli and results in the formation of the gas‐exchange surface of the lung. This developmentally regulated process involves a complex epithelium–mesenchyme interaction via evolutionarily conserved molecular signaling pathways. In addition, there is a continuous process of vascular growth and development. Currently there are large gaps in our understanding of the molecular mechanisms involved in the formation of the gas‐exchange (...) surface. In this review, we attempt to integrate and reconcile the morphologic features in late lung development with what is known about the molecular basis for these processes. We describe the formation of the terminal sac and the subsequent formation of the septa, which divide the terminal sac into alveoli, in terms of the classically described developmental stages of induction, morphogenesis and differentiation. We believe that evolutionarily conserved pathways regulate this process and that morphogen gradients are likely to be a central mechanism. In addition, we highlight the importance of the molecular mechanisms involved in the simultaneous development of the vascular bed and its importance in the late development of the lungs. BioEssays 24:1052–1059, 2002. © 2002 Wiley‐Periodicals, Inc. (shrink)

Development is a process whereby a relatively unspecified system comprised of loosely connected lower level parts becomes organized into a coherent, higher-level agency. Its temporal corollaries are growth, increasingly deterministic behavior, and a progressive reduction of developmental potential. During immature stages with relatively low specification and high potential, development is largely controlled by local interactions from the “bottom-up,” whereas during more highly specified stages with reduced potential, emergent autocatalytic processes exert “top-down” control. Robert Ulanowicz has shown that this phenomenology (...) of ascendency follows thermodynamic principles and can be described quantitatively using information theory, providing a general theory of development. However, the theory has not found a wide audience among developmental biologists, as genetic determinism encourages the popular reductionistic perception that ontogeny is controlled entirely by molecular mechanisms that exert efficient causality from the bottom-up. Nonetheless, measurements of metabolic rates and mRNA complexity in developing embryos, as well as functional analyses of gene regulatory systems, indicate that ontogeny fits the paradigm of developmental ascendency. Beyond informing biomedical research and the interpretation of large datasets obtained by systems-biological approaches, developmental ascendency helps explain the origin of life, and, being independent of scale, provides an overarching explanation for phylogenetic change that contextualizes Darwinian evolution. (shrink)

How do people gather samples of evidence to learn about the world? Adults often prefer to sample evidence from diverse sources—for example, choosing to test a robin and a turkey to find out if something is true of birds in general. Children below age 9, however, often do not consider sample diversity, instead treating non‐diverse samples (e.g., two robins) and diverse samples as equivalently informative. The current study (N = 247) found that this discontinuity stems from developmental changes in (...) standards for evaluating evidence—younger children chose to learn from samples that best approximate idealized views of what category members are supposed to be like (e.g., the fastest cheetahs), with a gradual shift across age toward samples that cover more within‐category variation (e.g., cheetahs of varying speeds). These findings have implications for the relation between conceptual structure and inductive reasoning, and for the mechanisms underlying inductive reasoning more generally. (shrink)

During embryogenesis, cell division must be spatially and temporally regulated with respect to other developmental processes. Leech embryos undergo a series of unequal and asynchronous cleavages to produce individually recognizable cells whose lineages, developmental fates and cell cycle properties have been characterized. Thus, leech embryos provide an opportunity to examine the regulation of cell division at the level of individual well‐characterized cells within a community of different types of cells. Isolation of leech homologues of some of the highly (...) conserved regulators of the cell division cycle, and characterization of their patterns of maternal and zygotic expression, indicate that the cell divisions of early leech embryos are regulated by cell type‐specific mechanisms. These studies with leech embryos contribute to the emerging appreciation of the diverse mechanisms by which animals regulate cell division during early development. (shrink)

In a recent opinion piece, Denis Duboule has claimed that the increasing shift towards systems biology is driving evolutionary and developmental biology apart, and that a true reunification of these two disciplines within the framework of evolutionary developmental biology may easily take another 100 years. He identifies methodological, epistemological, and social differences as causes for this supposed separation. Our article provides a contrasting view. We argue that Duboule’s prediction is based on a one-sided understanding of systems biology as (...) a science that is only interested in functional, not evolutionary, aspects of biological processes. Instead, we propose a research program for an evolutionary systems biology, which is based on local exploration of the configuration space in evolving developmental systems. We call this approach—which is based on reverse engineering, simulation, and mathematical analysis—the natural history of configuration space. We discuss a number of illustrative examples that demonstrate the past success of local exploration, as opposed to global mapping, in different biological contexts. We argue that this pragmatic mode of inquiry can be extended and applied to the mathematical analysis of the developmental repertoire and evolutionary potential of evolving developmental mechanisms and that evolutionary systems biology so conceived provides a pragmatic epistemological framework for the EvoDevo synthesis. (shrink)

I attempt to complement my earlier critiques of human sociobiology, by offering an account of how evolutionary ideas might legitimately be employed in the study of human social behavior. The main emphasis of the paper is the need to integrate studies of proximate mechanisms and their ontogenesis with functional/evolutionary research. Human psychological complexity makes it impossible to focus simply on specific types of human behavior and ask for their functional significance. For any of the kinds of behavior patterns that (...) have occupied human sociobiologists, the underlying proximate mechanisms are very likely to be linked to a broad spectrum of types of behavior, and we cannot expect that natural selection will have acted directly on any individual element from this spectrum. I illustrate this general point with a specific example, considering the traditional sociobiological account of human incest-avoidance and outlining an alternative approach to the phenomena. The example is intended to show the possibility of a more rigorous and sophisticated successor to human sociobiology, which I call "human behavioral ecology". (shrink)

This chapter examines an apparent tension created by recent research on neurological development and genetics on the one hand and cognitive development on the other. It considers what it might mean for intrinsic signals to guide the initial establishment of functional architecture. It argues that an understanding of the mechanisms by which the body develops can inform our understanding of the mechanisms by which the brain develops. It cites the view of developmental neurobiologists Fukuchi-Shimogori and Grove, that (...) the patterning of the part of the brain responsible for our higher functions is coordinated by the same basic mechanisms and signaling protein families used to generate patterning in other embryonic organs. Thus, what's good enough for the body, is good enough for the brain. (shrink)

A developmental theory of erotic/romantic attraction is presented that provides the same basic account for opposite-sex and same-sex desire in both men and women. It proposes that biological variables, such as genes, prenatal hormones, and brain neuroanatomy, do not code for sexual orientation per se but for childhood temperaments that influence a child's preferences for sex-typical or sex-atypical activities and peers. These preferences lead children to feel different from opposite-or same-sex peers — to perceive them as dissimilar, unfamiliar, and (...) exotic. This, in turn, produces heightened nonspecific autonomic arousal that subsequently gets eroticized to that same class of dissimilar peers: Exotic becomes erotic. Specific mechanisms for effecting this transformation are proposed. The theory claims to accommodate both the empirical evidence of the biological essen-. (shrink)

Most theories of learning would predict a gradual acquisition and refinement of skills as learning progresses, and while some highlight exponential growth, this fails to explain why natural cognitive development typically progresses in stages. Models that do span multiple developmental stages typically have parameters to “switch” between stages. We argue that by taking an embodied view, the interaction between learning mechanisms, the resulting behavior of the agent, and the opportunities for learning that the environment provides can account for (...) the stage-wise development of cognitive abilities. We summarize work relevant to this hypothesis and suggest two simple mechanisms that account for some developmental transitions: neural readiness focuses on changes in the neural substrate resulting from ongoing learning, and perceptual readiness focuses on the perceptual requirements for learning new tasks. Previous work has demonstrated these mechanisms in replications of a wide variety of infant language experiments, spanning multiple developmental stages. Here we piece this work together as a single model of ongoing learning with no parameter changes at all. The model, an instance of the Epigenetic Robotics Architecture embodied on the iCub humanoid robot, exhibits ongoing multi-stage development while learning pre-linguistic and then basic language skills. (shrink)

This article reviews recent research findings investigating developmental prosopagnosia. Studies involving DP address the cognitive and neural basis of face processing. The relatively rich cognitive, neural, and developmental theories of face recognition provide a framework that should allow for rapid progress. Cognitive studies of DP provide support for the existence of face-specific processes, and dissociations between different types of face processing in DPs are consistent with leading models of face processing that propose separable mechanisms for various aspects (...) of face processing. Research on the neural basis of DP has found abnormalities in a number of occipital and temporal regions that show face-selective responses in people with normal face processing, and so provide additional evidence that the integrity of these areas is necessary for face recognition. Despite progress made in recent years, much work remains to be done and connections between cognitive, neural, developmental, and genetic levels of explanation remain to be worked out. (shrink)

It has been suggested that there is a close relationship between visual attention span (VAS) and fluent reading. This relation may be modulated by participants’ age, and exhibits various patterns in different reading modes (i.e. oral v.s. silent reading) and different reading levels (e.g. sentence v.s. character/word levels). Moreover, the modulation effects from the above factors might be more remarkable in the framework of languages with a deep orthography. Therefore, the present study investigated the developmental pattern of the relationship (...) between VAS skills and reading fluency in Chinese, a language with particularly deep orthography, by recruiting 292 participants from primary schools, middle schools and universities. Two tests were utilized to assess fluent reading skills at the single-character and sentence levels with oral and silent reading modes. A visual 1-back task was adopted to reflect VAS capacity with non-verbal stimuli and no verbal response. Results showed that the VAS capacity of low-grade primary school students could significantly account for the variance in single-character reading fluency in the oral mode and that it was a significant predictor of sentence reading fluency in the oral mode among high-grade primary school students. VAS abilities of middle school students allowed a unique and stable prediction of their silent sentence reading. With increasing reading ability, VAS skills of adults showed significant and similar predictive power for estimating the variations in fluent sentence reading in both silent and oral modes. These results revealed developmental changes in the contribution of VAS to fluent reading in Chinese, and provided evidence unveiling whether the underlying mechanisms of oral and silent reading were shared or different. (shrink)

Have the large-scale evolutionary patterns illustrated by the fossil record been driven by fluctuations in environmental opportunity, by biotic factors, or by changes in the types of phenotypic variants available for evolutionary change? Since the Modern Synthesis most evolutionary biologists have maintained that microevolutionary processes carrying on over sufficient time will generate macroevolutionary patterns, with no need for other pattern-generating mechanisms such as punctuated equilibrium or species selection. This view was challenged by paleontologists in the 1970s with proposals that (...) the differential sorting and selection of species and clades, and the effects of biotic crises such as mass extinctions, were important extensions to traditional evolutionary theory. More recently those interested in macroevolution have debated the relative importance of abiotic and biotic factors in driving macroevolutionary patterns and have introduced comparative phylogenetic methods to analyze the rates of change in taxonomic diversity. Applying Peter Godfrey-Smith’s distinction between distributional explanations and explanations focusing on the origin of variation, most macroevolutionary studies have provided distributional explanations of macroevolutionary patterns. Comparative studies of developmental evolution, however, have implicated the origin of variants as a driving macroevolution force. In particular, the repatterning of gene regulatory networks provides new insights into the origins of developmental novelties. This raises the question of whether macroevolution has been pulled by the generation of environmental opportunity, or pushed by the introduction of new morphologies. The contrast between distributional and origination scenarios has implications for understanding evolutionary novelty and innovation and how macroevolutionary process may have evolved over time. (shrink)

The mechanisms responsible for the fine tuning of development, where the wildtype phenotype is reproduced with high fidelity, are not well understood. The difficulty in approaching this problem is the identification of mutant phenotypes indicative of a defect in these fine‐tuning control mechanisms. Evolutionary biologists have used asymmetry as a measure of developmental homeostasis. The rationale for this was that, since the same genome controls the development of the left and right sides of a bilaterally symmetrical organism, (...) departures from symmetry can be used to measure genetic or environmental perturbations. This paper examines the relationship between asymmtry and resistance to organophosphorous insecticides in the Australian sheep blowfly, Lucilia cuprina. A resistance gene, Rop‐1, which encodes a carboxylesterase enzyme, also confers a significant increase in asymmetry. Continued exposure of resistant populations to insecticide has selected a dominant suppressor of the asymmetry phenotype. Genetic evidence indicates that the modifier is the L. cuprina Notch homologue. (shrink)

I would like to stress that early development repeats the evolution of the species. Hence, to understand the origins of functional brain asymmetry and the underlying mechanisms involved in handedness, we have to seek information not only from what we know about human evolution, but also from how an early hand preference develops in our own species.

Measurements of open chromatin in specific cell types are widely used to infer the spatiotemporal activity of transcriptional enhancers. How reliable are these predictions? In this review, it is argued that the relationship between the accessibility and activity of an enhancer is insufficiently described by simply considering open versus closed chromatin, or active versus inactive enhancers. Instead, recent studies focusing on the quantitative nature of accessibility signal reveal subtle differences between active enhancers and their different inactive counterparts: the closed silenced (...) state and the accessible primed and repressed states. While the open structure as such is not a specific indicator of enhancer activity, active enhancers display a higher degree of accessibility than the primed and repressed states. Molecular mechanisms that may account for these quantitative differences are discussed. A model that relates molecular events at an enhancer to changes in its activity and accessibility in a developing tissue is also proposed. (shrink)

More than 40 years ago, Gilbert Gottlieb and like-minded scholars argued for the philosophical necessity of approaching genetic contributions to development through a multilevel, bidirectional systems perspective. Charney's target article builds on this heritage in significant ways, offering more recent examples of the interactions of biology and context, as well as the diversity of developmental mechanisms, and reaffirming a way forward for genetic research.

Empathy is thought to play a key role in motivating prosocial behavior, guiding our preferences and behavioral responses, and providing the affective and motivational base for moral development. While these abilities have traditionally been examined using behavioral methods, recent work in evolutionary biology, developmental and cognitive neuroscience has begun to shed light on the neural circuitry that instantiate them. The purpose of this article is to critically examine the current knowledge in the field of affective neuroscience and provide an (...) integrative and comprehensive view of the computational mechanisms that underlie empathy. This framework is of general interest and relevance for theory as well as for assisting future research in the domains of affective developmental neuroscience and psychopathology. (shrink)

Organogenesis and metamorphosis require the intricate orchestration of multiple types of cellular interactions and signaling pathways. Glutamate (Glu) is an excitatory extracellular signaling molecule in the nervous system, while Ca2+ is a major intracellular signaling molecule. The first Glu receptors to be cloned are Ca2+‐permeable receptors in mammalian brains. Although recent studies have focused on Glu signaling in synaptic mechanisms of the mammalian central nervous system, it is unclear how this signaling functions in development. Our recent article demonstrated that (...) Ca2+‐permeable AMPA‐type Glu receptors (GluAs) are essential for formation of a photosensitive organ, development of some neurons, and metamorphosis, including tail absorption and body axis rotation, in ascidian embryos. Based on findings in these embryos and mammalian brains, we formed several hypotheses regarding the evolution of GluAs, the non‐synaptic function of Glu, the origin of GluA‐positive neurons, and the neuronal network that controls metamorphosis in ascidians. (shrink)

The developmental programs of eukaryotic organisms involve the programmed transcription of genes. A characteristic gene expression pattern is established and preserved in each different cell type. Therefore, gene activation at a particular time and its maintenance during cell division are significant for cellular differentiation and individual development. Although many studies have sought to explain the molecular mechanisms of gene expression regulation, the mechanism through which gene expression states are inherited during cell division has not been fully elucidated yet. (...) This review illustrates the general principles and the complexities involved in the establishment and maintenance of active transcription through cell cycles. It focuses on the most‐recent findings about the ways in which molecular memory marks for active transcription are coordinated with cell cycle events, such as replication, mitosis and nuclear organization, to mediate transcription memory across cell division events, which may establish a unifying memory process of active transcription. BioEssays 27:1239–1245, 2005. © 2005 Wiley Periodicals, Inc. (shrink)

Children with developmental language disorder (DLD) served as a test case for determining the role of extant vocabulary knowledge, endogenous attention, and phonological working memory abilities in cross-situational word learning. First-graders (Mage = 7 years; 3 months), 44 with typical development (TD) and 28 with DLD, completed a cross-situational word-learning task comprised six cycles, followed by retention tests and independent assessments of attention, memory, and vocabulary. Children with DLD scored lower than those with TD on all measures of learning (...) and retention, a performance gap that emerged in the first cycle of the cross-situational protocol and that we attribute to weaknesses in initial encoding. Over cycles, children with DLD learned words at a similar rate as their TD peers but they were less flexible in their strategy use, demonstrating a propose-but-verify approach but never a statistical aggregation approach. Also, they drew upon different mechanisms to support their learning. Attention played a greater role for the children with DLD, whereas extant vocabulary size played a greater role for the children with TD. Children navigate the problem space of cross-situational learning via varied routes. This conclusion is offered as motivation for theorists to capture all learners, not just the most typical ones. (shrink)