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Biology And Knowledge Revisited: From Neurogenesis To Psychogenesis by Jonas Langer, Sue Taylor Parker, Constance Milbrath (Jean Piaget Symposium Series: Lawrence Erlbaum Associates) Based on the Annual Symposium of the Jean Piaget Society, Biology and Knowledge Revisited focuses on the classic issue of the relationship between nature and nurture in cognitive and linguistic development, and their neurological substrates. Contributors trace the history of ideas concerning the relationship between evolution and development, and bring powerful new conceptual systems and research data to bear on understanding the problem of experience-contingent brain development and evolution. They focus on processes of phenotype construction--which fills the gap between genes and behavior--and demonstrate that evolutionary psychological models of innate mental modules are incompatible with what is known about these processes. This book presents exciting new approaches to the development and evolution of cognitive and linguistic abilities. Returning to the broad evolutionary theme of a previous meeting, the symposium focused on specifically constructivist approaches to neurogenesis and language acquisition, and their evolution. It was organized around ideas about the relationship between development and evolution raised in Piaget's books. Treated in the chapters of this book, research in this arena has yielded cutting-edge insight into behavioral influences on brain plasticity. Two of its subthemes run throughout--a critique of modularity models popular among evolutionary psychologies and the prescient yet flawed nature of Piaget's critique of the modern synthesis of evolution. As a result, Biology and Knowledge Revisited is intended for developmental psychologists, psycholinguists, biological anthropologists, evolutionary psychologists, and philosophers of science.
Excerpt: Comparative cross-species and cross-cultural approaches to studying the evolutionary and developmental relations between biology and knowl­edge have a long and rich history. Key, on the one hand, is inquiry into how conceptual, perceptual and linguistic behavior grows out of yet ex-tends beyond its roots in the evolution of brain development. This has re­ceived the most research attention. Key, on the other hand, is inquiry into how behavior influences and enters into regulating the development and evolution of the brain.

These are the two reciprocal inquiries that Piaget (1971) explored in his seminal, if at times controversial examination entitled Biology & Knowl­edge: An Essay on the Relations between Organic Regulations & Cognitive Processes. Accordingly, the evolutionary theme of the 31st annual Meet­ing of the Jean Piaget Society in 2001 was inspired by our desire to revisit ideas Piaget developed in Biology and Knowledge. The organizers sought to stimulate reconsideration of these ideas in light of recent comparative research in evolutionary developmental biology, neurobiology, and cog­nitive development. In particular we wanted to focus on epigenetic mod­els of cognitive and language development in relation to the evolution of brain development.

The 2001 Meeting returned to the broad evolutionary theme of the 25th annual Meeting on Piaget, evolution, and development held in 1995 . It differed from the earlier meeting, however, in being organized around ideas about the relationship between development and evolution raised in Piaget's books. It also differed in focusing on specifically constructivist approaches to neurogenesis and language acquisition, and their evolution.

As a uniquely human characteristic, language has long fascinated psy­chologists, anthropologists, and biologists. It is both species-specific and developmentally plastic, and completely dependent on participation in a linguistic environment. It is both a product of, and a contributor to cul­tural niche construction  1988). As such, it has driven the increasing pace of human biological and cultural evolution. Recognizing this and the power of constructivist mod­els, all the contributors to this volume approach the evolution and devel­opment of human linguistic and cognitive abilities, and their neural substrates, from epigenetic constructivist perspectives. They all emphasize environment-contingent plasticity of behavioral and brain development. They all employ comparative methodologies in their analyses, whether comparative linguistic studies (Slobin, chap. 8, and Senghas, Senghas, and Pyers, chap. 9), comparative studies of developmental disorders (Bates, chap. 7, and Karmiloff-Smith & Thomas, chap. 10), or comparative spe­cies studies (Gallese, chap. 6, Gibson, chap. 4, and MacLeod, chap. 5).

Two chapters focus on language development and language change, addressing implications these phenomena may have for understanding the evolution of language capacity. Dan Slobin (chap. 8) addresses the following hotly debated questions: whether linguistic ontogeny recapitu­lates its phylogeny, whether language change recapitulates its ontogeny, and whether children create grammatical forms. He concludes that there is no universal form of early child language that clearly reflects a biologi­cally specified proto-language. Second, he concludes that innovations in historical change in existing languages come from older speakers rather than from preschool aged children as Bickerton (1981, 1990) and others have suggested. Finally, he concludes that because languages are sociocultural products, studies of individuals alone cannot illuminate the phy­logeny of linguistic abilities as evolutionary psychologists have suggested. On a more positive note, however, he says that "Children's homesign sys­tems suggests a human capacity to create something like a protolanguage.... However, for such a language to develop further, a commu­nity of users is needed."

The question of what role language users of different ages play in his­torical change in language is also addressed by Richard and Anne Sen­ghas and Jennie Pyers' (chap. 9). These investigators describe the emer­gence of the new Nicaraguan Sign Language (NSL) among deaf children given increasing opportunities to interact socially with other deaf children during the past 25 years. They describe three historical periods: (1) the Pre-Emergence period characterized by social isolation of deaf people and use of isolated homesigns; (2) the Initial Contact period in 1977, which established vocational programs for deaf adolescents; and (3) the Sustained Contact period in the mid-1980s, in which a Deaf Association formed and began to assume control of learning and established a dictio­nary project and brought signing deaf models to schools.

They divided the signers into two historical cohorts: The first cohort entered the community between 1978 and 1983; the second cohort, be­tween 1984 and 1990. They also divided signers to three age grades ac-cording to their age at first year of exposure to language: (1) late exposed, more than 10 years of age at exposure; (2) middle-exposed, between 6 and 10 years of age at exposure; and (3) early exposed, less than 6 years of age at exposure. In order to tease apart historical and age variables, they com­pared the grammar of individuals exposed to signing at different ages in different periods.

When they examined the use of spatial co-reference, they discovered that in the 1980s the first cohort began employing these modulations more frequently, and that children in the late 1980s began to impose a new con­straint by which signs produced in the same location had a common refer­ent, making the signing more specific. Further analysis revealed that whereas middle and early exposed signers in the second cohort used the common referent modulations, late-exposed signers from both cohorts were unlikely to produce spatial co-reference. From this they conclude that spatial co-reference is not as easy to learn for older signers. Consis­tent with Slobin's conclusions, they emphasize that ". . . language genesis requires at least two cohorts of the community in sequence, the first pro­viding the circumstances that the second can exploit."

In a complementary approach to arguments about language acquisi­tion and modularity, Karmiloff-Smith and Thomas (chap. 10) employ a `"neuro-constructivist" approach to assessing claims that children with William's Syndrome provide evidence for innate mental modules. This claim is based on the supposition that these children display linguistic and social skills far beyond those typical of their retarded mental age. The au­thors emphasize the importance of going beyond descriptions of adult disabilities to trace the development of infants and children with this disorder across both apparently normal and abnormal behavioral systems. Their analysis of Williams Syndrome (WS) shows that, contrary to claims of evolutionary psychologists, language comprehension and production of children with WS as compared to normal children was either very de­layed or that behavioral scores "in the normal range" were sustained by atypical cognitive processes. In fact, their vocabulary, syntax, and usage were all deficient. Moreover, these deficits and those in their social cogni­tion including face recognition are consistent with their degree of mental retardation, rather than strikingly superior to their general mental abilities, as suggested by evolutionary psychologists. Taken together, their studies suggest that children with these syndromes follow atypical trajec­tories and display atypical brain development.

In another powerful approach to understanding language acquisition, Liz Bates (chap. 7) , to whom this volume is dedicated, describes the implications of prospective studies of language development in children from different language communities who have suffered early focal brain injuries. Rather than supporting a model of innate representations based on a universal architecture, these studies reveal that localization is plastic and modifiable by experience, therefore it is variable. Competitive pres­sures and relatively simple biases in computation style underlie specific localizations of function that develop through experience in both normal and abnormal development. As she says, "... most of the brain participates in linguistic activity, in varying degrees, depending on the nature of the task and the individual's expertise in that task." This suggests that "language facilitating mechanisms" are widely distributed in the brain, and predated language evolution. Both Bates (chap. 7) and Karmiloff-Smith and Thomas (chap. 10) argue that any language modularity that can be seen in adult brains is a distributed, contingent product of development rather than an innate organ.

In combination, these chapters reveal the plasticity and contingency of language development. Among other things, they reveal that the course of language acquisition depends on the dynamic interplay of internal factors (e.g., auditory and/or visual perception, brain injury or lack of injury, and/or typical or atypical genotypes) and external factors (e.g., the exis­tence and nature of the linguistic community, as well as the organization of the local language). They also reveal how aspects of language acquisi­tion and localization of these aspects depend upon the age at which chil­dren experience these various factors. On the other hand, they reveal the resilient and robustly multimodal nature of the symbolic capacity, which has led some investigators to misinterpret it as an innately programmed neural module.

In a chapter on evolution, Kathleen Gibson (chap. 4) takes a compara­tive developmental approach to the brain. She contrasts the increasingly complex, hierarchical mental constructional capacities of humans with the lesser capacities of great apes, who achieve cognitive and linguistic abilities comparable to those of 2-to 3-year-old humans. These greater ca­pacities are reflected in both the increased size not only of the human neocortex, but of the basal ganglia and cerebellum, as well as the more pro-longed period of brain development. Gibson also emphasizes that models of human evolution must recognize continuities between the minds of humans and those of great apes, with whom we share a recent common an­cestor. Like other contributors to this volume, she rejects the model of "genetically determined, functionally dedicated neural modules" for lan­guage, noting that brain development is epigenetic and highly contingent on experience. She also notes, however, that similar environments and self-generated behaviors combine to channel development into predict-able, species-specific patterns.

In a more specific approach to brain evolution, Carol MacLeod (chap. 5) uses the comparative species perspective to focus on the evolution of the cerebellum. She explains that "the cerebellum functions as a partner with the neocortex, processing information, but never sending direct commands to the body except through intermediaries." She notes that whereas the phylogenetically older, medial and anterior part of the cere­bellum is involved in the execution of movement, the newer, lateral part is involved in planning movements, and hence in cognition. In her compara­tive study of ape and human brains, she discovered that greater and lesser apes as compared with monkeys show a significant increase in the size of the lateral cerebellum. She argues that this "grade level change" (shared by several sequential ape lineages) provided a springboard for superior cognitive and linguistic adaptations of hominoids.

In a daring new approach, Vittorio Gallese (chap. 6) addresses the human capacity for intersubjectivity, which underpins both language and such elements of social cognition as imitation and empathy. He describes his discovery of the "mirror neurons" in the ventral premotor cortex of macaque monkeys. These neurons respond specifically and uniquely to the sight or sound of grasping actions (by the hand or mouth) performed on object by the self  on another individual: "Such a neural mechanism en-

ables the monkey to represent the end-state of the interaction independ­ently from the different modes of presentation. . . ." On the basis of these mirror neurons, Gallese proposes the "shared manifold hypothesis" that ". . . a similar mechanism could underpin our capacity to share feelings and emotions with others."

Taken together, these various contributions suggest the power of com­parative epigenetic constructivist models to illuminate the development and evolutionary history of human linguistic and cognitive capacities. As such, they follow in the larger tradition of Piaget's constructivist para­digm and begin to address some of his questions without resorting to Lamarckian mechanisms.

Chapter 1 examines Piaget's constructivist paradigm in relation to some historic and recent models for the role behavior and development play in evolution. These include the Baldwin effect or organic selection (Baldwin, 1896), niche construction (Laland, Odling-Smee et al., 1999; Odling-Smee, Laland et al., 1996), and phenotype centered evolution (West-Eberhard, 2003). All these models reflect a growing trend in evolu­tionary biology to emphasize the phenotype rather than the genotype.

In contrast, chapter 2 of this volume focuses specifically on the pheno­copy model, the mechanism Piaget (1978) proposed to explain the role of behavior and development in the origin of heritable adaptive variations. Piaget's ideas are examined in the context of his own intellectual history, and the history of ideas about this important subject going back to Lamarck (1984), through Darwin and the modern synthesis (Mayr & Provine, 1989), and beyond to the growth of developmental molecular bi­ology. Although Piaget's phenocopy model does not stand up in light of modern developmental molecular biology, it addresses important ques­tions about the origins of variations that have only recently begun to be investigated.

Likewise, Terrance Deacon's chapter 3 analyzes the epistemology of Piaget's attempt to devise a unified theory of development and evolution in a cybernetic model of auto regulation. He argues that even though Piaget was unable to achieve this synthesis, he recognized "critically in-complete" aspects of neoDarwinism, which are only now being ad-dressed. He notes that Piaget's model, like those of Spencer (1872) and Lamarck (1984), is based on active adaptive agency in both developmen­tal and evolutionary domains. He says that Piaget saw Baldwin's (1896) organic selection and Waddington's phenocopy (1975) model as showing indirect ways that development could affect the germ plasm. However, Deacon argues. that, contrary to Piaget's phenocopy model, Wad­dington's (1975) genetic assimilation, Weismann's (1892) intraselection, and Baldwin's organic selection all involve developmental influences on evolution that work through Darwinian processes of selection rather than Lamarckian processes. Moreover, Deacon argues that development itself relies on Darwinian selection-like processes. He summarizes studies dem­onstrating how activity-dependent competition between signal pathways can create emergent properties in developing neurological systems. He concludes that, "Piaget's appeal to both Baldwin and Waddington can now be seen as insightful anticipations of a necessary complexification of evolutionary theory, though neither a repudiation of Darwinian mecha­nisms nor a return to Lamarckian paradigms. To explain the apparent autoregulatory power of biological evolution, does, as he suspected, re-quire incorporating the role of epigenetic processes as mediators between genotype and phenotype. Yet there turns out to be a far more prominent role for Darwinian over cybernetic mechanisms of regulation in both de­velopment and evolution than Piaget could ever have imagined."

 

Emotional Development: Recent Research Advances edited by Jacqueline Nadel, Darwin Muir (Oxford University Press) (Paperback) From prenatal life onwards, our emotions play a central role in our development. Exactly how emotions shape our lives is less clear. We know that emotional impairments can have a disastrous effect on development. We know that emotions play a key role in adaptation. We know that traumatic emotional events can scar individuals. The processes through which these emotional changes occur is complex however, and has recently become the subject of considerable interest in the cognitive sciences. In this volume an outstanding group of scientists considers emotional development from fetal life onwards. The book includes views from neuroscience, primatology, robotics, psychopatholgy, and prenatal development. It also includes studies of emotional development in both normal and clinical populations. The first of its kind, this book will be of major interest to all those studying emotion, from the fields of social, developmental, and clinical psychology, to psychiatry, and neuroscience.

Excerpt: It took us 120 years to follow Darwin's seminal insight on the importance of emotion for evolution and development, and to alter the traditional view that: (1) emotions simply reflect underlying physiological states that needed to be controlled (held constant) in experimental work on cognition and social development; and (2) abnor­mal emotional regulation by individuals classified as `emotionally disturbed' simply blocks cognitive and social development with devastating results. The primary lesson we learned from the Darwinian perspective that was revisited about 25 years ago is that the importance of emotion increases with the complexity of the species. Far from being an impediment, emotional processes play a key role in adaptation. Our ability to recognize and respond to the emotional signals of others shapes our attention and disposition; this ability allows us to choose, according to our hedonic preferences, between several solutions that are equally available. Our own emotional displays give others a look inside us. Once we develop that insight about how much information we offer when we express ourselves, we start to disguise our emotional signals in order to present the public view that we would like others to believe about what we feel (see Scherer et al., 2001, OUP). Before mastering this key to our individuality, we begin life by sharing our emotional brain neurochemistry with our mother. According to whether or not this neurochemistry is optimal, we are more or less likely to experience stress with its cascade of effects on cognition, socialization, and metacognition. In this book, based on recent research advances in the study of emotions in typical and clinical populations, leading specialists in the field of emotional development discuss the factors that optimize emotional development, on one hand, and result in various psychopathologies, on the other.

General description of the contents for each section

In Section I, readers will receive an update on issues concerning neural bases and evolution of emotional development, and a review of the latest work on the ontogeny

of emotional reactions. We include several chapters on the emotional reactions of fetuses and newborns. The emergence and refinement of emotional responses and per­sonality characteristics during the first few years of life are discussed, with emphasis on both the perception of emotional signals and the emergence of Theory of Mind pro­cessing in human infancy. This section ends with chapters outlining the latest technical advances in computer technology related to the study of emotional development (e.g. interactions with virtual adults, building an emotional robot).

In Section II, comparative studies of typical and impaired emotional development are covered. Seven chapters will cover clinical applications in the study of infants and chil­dren with disorders of emotional regulation and affect, including maternal/childhood depression, autism, obsessive-compulsive disorders, and anhedonia. The effects of early emotional dysfunction on social and cognitive development will be discussed.

Finally, the options and data presented in the book are discussed and an overview is presented.

The challenge for each of our contributors was to write a chapter that provides the readers with a description of the most recent research and theory in their fields of expertise, plus a preview of where their field is heading. A unique aspect of this collection is the relatively equal space given to research on both average and clinical populations. Increasing scientific attention on the role of emotions in human development has led to major interdisciplinary advances. The intention is to appeal to a very broad audience of scientists who need to be informed about the latest advances in the study of emotional development.

 

Section I. Psychobiological approaches and evolutionary perspectives

A major feature of this section is the emphasis on an evolutionary perspective by many of the contributors, and a general agreement that emotional processes are central motivators designed to organize cognition and action.

Neural basis of emotions and evolutionary perspectives

Jaak Panksepp and Marcia Smith-Pasqualini point out that humans begin to navigate the complexities of the world, and to learn about the values and contingencies of the environment at birth. They review brain imaging studies and recent advances in understanding basic emotional systems of the mammalian brain, and implications for understanding the nature of affective feelings in humans.

A discussion of the evolutionary perspective is provided in the next two chapters. Kim Bard studies the reactions of newborn chimpanzees during their interactions with human adults. She has discovered that newborn chimpanzees respond emotionally in a similar manner to newborn humans. They express interest and joy (smiling) during positive engagements, and anger and fear when humans violate their `social expectations.

Colwyn Trevarthen introduces the argument that emotions are proactive in the human mind. He suggests that the evolution of the social functions of emotions and of inter-subjective behaviours in infancy lead to cultural learning and language acquisition.

 

Ontogeny

The ontogeny of emotional development is complex and begins prior to birth. Amy Salisbury, Penelope Yanni, Linda Lagasse, and Barry Lester introduce this section by demonstrating, with ultrasound techniques, that fetuses react to emotional events. Furthermore, they suggest that the physiological and psychological state of fetuses experiencing persistent stress via their mothers may be modified when their mothers receive appropriate prenatal medication.

The basic question about the level of organization and differentiation of emotional systems early in life is considered in the next three chapters. Robert Soussignan and Benoist Schaal describe the early plasticity of emotional responses, showing, for instance, that immediately after birth, human newborns display various facial expressions to positive and negative stimuli that may be related to fetal exposure to these stimuli. Giannis Kugiumutzakis, Theano Kokkinaki, Maria Makrodimitraki, and Elena Vitalaki present evidence of strong emotional reactions during imitative inter-actions between newborns and adults. They emphasize the need for naturalistic studies of spontaneous imitation to comprehend the emotional components of imitation that until now have been largely neglected. This sub-section is concluded by Vasudevi Reddy who provides new evidence of early self-awareness and its influence on the development of emotions often thought to be secondary emotions, such as shyness. She reports that both shyness and showing off may be present as early as 2 months of age.

 

New technology

New technologies are covered in the last two chapters of this first section. Darwin Muir, Kang Lee, Christine Hains, and Sylvia Hains introduce two new software programmes for studying emotional development. They describe a free program on the Internet for frame-by-frame coding of videotapes of the emotional expressions of both infants and adults during face-to-face interactions. They also have produced a `virtual adult' that is effective in engaging infants as young as 3 months of age in face-to-face interactions. Manipulations of the computer display demonstrate how sensitive young infants are to various perturbations in adult facial and vocal expressions.

Lola Cañamero and Philippe Gaussier introduce affective computing. They adopt a bottom-up approach in their attempt to build autonomous robotic systems, which are animal-like automata, called `animats. This work is of interest not only for robotics, but also for developmental psychology. Cañamero and Gaussier discuss the importance of emotional components to a system that faces several simultaneous problems. They conclude that emotions can be considered as a second-order controller, monitoring the system's activity, and providing interfaces between a robot and other agents in the environment.

Section II. Comparative approaches: typical and impaired emotional development

If emotions are organizers for development itself, as most of us claim, emotional impairments should have disastrous effects on social, as well as on cognitive development. Unfortunately, little is known to-date about mediating processes or processes that are specific to emotions. The field of developmental psychopathology offers a rich source of information concerning the effect of abnormal emotional development on perceptual, cognitive, and social epigenesis. Harriet Oster uses her Baby FACS system to show that infant facial expressions are universal biologically-based adaptations. Her coding system highlights the developmental differences in facial emotional expres­sions produced by infants with atypical facial morphology, compared with typical populations.

Although emotion regulation is critical in initiating, motivating and organizing adaptive behaviour, and preventing stress, researchers have just begun the work of describing the processes of emotion regulation in infancy and childhood. The study of maternal depression is one of the more promising bases for such descriptions. Tiffany Field shows that maternal depression has a negative effect on infant behaviour and physiology, even during the prenatal period. Field proposes that the negative effects result from both the prenatal exposure to an imbalanced physiological and hormonal environment and the postnatal exposure to an emotionally unavailable mother who is unable to provide the infant with adequate stimulation and arousal modulation. She thus highlights the importance of considering dyadic states.

Edward Tronick introduces his new model of infant–mother interaction—the `Dyadic States of Consciousness' (DSC)—following, in part, from his Still-Face procedure. According to his DSC hypothesis, Tronick predicts that infants who interact with depressed parents will seek out sad states of consciousness if that is the only way they can achieve DSC. Tronick's focus on dyadic states has important theoretical and methodological implications and leads us to the argument for a two-body psychology, which emphasizes the importance of the use of an interactive context to study emo­tional development and regulation.

The use of a two-body psychology is shared by many of the contributors in Section I, and all the contributors in Section II. Within the two-body framework, Hélène Tremblay, Philippe Brun and Jacqueline Nadel describe the links between emotion and the evolving self-other system. They stress the importance of situated studies of emotion besides studies of emotion knowledge in children with typical and impaired development.

Katherine Loveland also emphasizes the importance of the context in the study of emotional regulation. Using a Gibsonian framework (ecological psychology), she pres­ents an interactive view of the autistic spectrum disorder as a discordant relationship between a person and his/her environment throughout development. She argues that a model of brain dysfunction in autism must include not only those structures and

systems that subserve social cognition and emotion recognition, but also those that subserve the regulation of behaviour in response to a changing social environment.

It has been proposed that some regulatory processes are aimed at establishing specific emotional states, whereas others have emotion-cognition and emotion-action links. Martine Flament and David Cohen address this issue by examining psychological, biochemical and neurological models of obsessive-compulsive disorders in children.

Another disease model that focuses on the link between positive emotions and cogni­tion is anhedonia (the inability to experience pleasure). Stéphanie Dubal and Roland Jouvent review the literature on anhedonia and discuss their research, which demonstrates a relationship between anhedonia and attention deficits. Their work on emotional impairments in late adolescence illustrates the link between emotional development research and the work on the relationships between emotion and cognition in adults.

In the final chapter, George Downing discusses novel targets, tools, ideas, research designs, and frameworks that emerged from the 16 chapters on typical and impaired emotional development.

 

Examination Notes in Psychiatry, 4th Edition by Peter Buckley, Del Prewette, Jonathan Bird, Glynn, M.D. Harrison (Arnold Publication) As with any subject worthy of human study and endeavor, psychiatry develops, understandings change, new facts emerge or old ones are seen in a new light. Since the first edition of this book some 20 years ago there have been tremendous advances in neuroscience and, as a result, major new insights into the functioning of the brain have emerged. Yet, at the same time, major changes are also taking place in the organ­ization and delivery of mental health services throughout the world.

We hope that the fourth edition of this widely read text will prove even more useful to mental health trainees of various disciplines (psychiatrists, psychologists, nurses and other professionals), to interested medical students, and to mental health clinicians wishing to prepare lectures or brush up on the main essentials of psychiatry. This edi­tion has been almost totally revised and, inevitably, expanded. Almost every subject has been revisited in the light of the most current knowledge and theories. `New' conditions (e.g. Internet addiction) and new investigations (e.g. functional MRI) sit beside all the old favourites.

References are included where these are considered to be `key' papers or reviews which could be quoted and which readers should look up for themselves. There are also suggestions for further reading.

Finally, we would reiterate what we have written in previous prefaces, that this book is not intended as a substitute for wider reading or experience, but as a detailed and comprehensive aide-mémoire. In order to gain fluency in the subject, readers might carry it with them, rehearse its content, follow up its references, debate its currently received wisdom and enjoy the fruits of their labours by achieving the success that their endeavours deserve.

 

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