Whereas the cerebral specialization for skilled manual actions (praxis) seems closely linked to dominance for language, with both functions left lateralized in the vast majority of humans, the neural correlates of hand preference are still less well understood. Indeed, as a combination of inherited and non-inherited genomic factors (i.e., direct parental and concealed environmental contributions), handedness – in contrast to language – is less likely to have strong genetic indices and clearly lateralized functional organization. What about eye dominance, unimanual and bimanual object manipulation, and gestures, or attentional systems and the related egocentric or allocentric coding of space? Are these different categories functionally and structurally interconnected? Is their development and contribution to task performance linked, even if they are differently lateralized? How are they connected to language learning or its development? In trying to understand these relationships and their neural underpinnings we obtain a new insight into fundamental human behaviors, which depend either on shared or distinct cerebral resources that must, nevertheless, be harmonized by higher-order cerebral processing. In this Research Topic we assembled a dozen of original research contributions, as well as articles with more theoretically-driven perspectives, that directly speak to these issues. Hopefully this work will serve as a foundation for further discussions and will stimulate new research in this fascinating domain.

This book represents a broad integration of several major themes in psychology toward its unification. Unifying psychology is an ongoing project that has no end-point, but the present work suggests several major axes toward that end, including causality and activation-inhibition coordination. On the development side of the model building, the author has constructed an integrated lifespan stage model of development across the Piagetian cognitive and the Eriksonian socioaffective domains. The model is based on the concept of neo-stages, which mitigates standard criticisms of developmental stage models. The new work in the second half of the book extends the primary work in the first half both in terms of causality and development. Also, the area of couple work is examined from the stage perspective. Finally, new concepts related to the main themes are represented, including on the science formula, executive function, stress dysregulation disorder, inner peace, and ethics, all toward showing the rich potential of the present modeling.

The growth of clinical neuropsychology has been unprecedented. This growth has been oriented more toward the provision of than toward the foundation for services. Thus, while a greater number of psychologists are performing a greater number of neuropsychological procedures, there seems to us an uneven parallel growth between these services and the empirical foundations for them. It should come to no one's surprise that increasingly aggressive attacks on the field have been leveled. Despite these attacks, clinical neuropsychology con tinues to enjoy exceptional growth within psychology and acceptance by other health practitioners, insurance companies, legislators, judges, juries, and above all, consumers of our services. Growth without self-reflection is a dangerous enterprise, as is growth without directions. We find it disconcerting that existing and limited "self analysis" has assumed that neuropsychological dysfunction is immune to the same variables that affect psychological dysfunction. Some attention has been paid to the most obvious ones, such as age, but all others have been ignored and/ or misunderstood. This neglect has spawned a body of knowledge replete with questionable data and unfounded conclusions. Hence, it is surprising that clinical neuropsychologists consider themselves to be more scientifically sound than their regular clinical counterparts.

Ronald Reagan and Barack Obama have both signed bills into law with their left hands. And being left-handed certainly did not hold back the artistic achievements of Michelangelo or Raphael. And the dexterous guitar playing of Jimmi Hendrix may only have been aided by his southpaw tendencies. Left-handedness, in fact, would appear to be no big deal. Yet throughout history, it has been associated with clumsiness and generally dubious personality traits like untrustworthiness and insincerity. Even the Latin word for left, sinister, has ominous connotations. In The Puzzle of Left-handedness, Rik Smits uncovers why history has been so unkind to our lefthanded forebears. He carefully puts together the pieces of the puzzle, presenting an array of historical anecdotes, strange superstitions, and weird wives’ tales. Smits explains how left-handedness continues to be associated with maladies of all kinds, including mental retardation, alcoholism, asthma, hay fever, cancer, diabetes, insomnia, depression, and criminality. Even in the enlightened twenty-first century, left-handedness still meets with opposition—including from one prominent psychologist who equates it with infantile negativism, similar to a toddler’s refusal to eat what’s on his plate, and another who claims that left-handed people have average lifespans that are nine years shorter than those who favor the right hand. As Smits reminds us, such speculation is backed by little factual evidence, and the arguments presented by proponents of right-handedness tend to be humorously absurd. The Puzzle of Left-handedness is an enlightening, engaging, and entertaining odyssey through the puzzles and paradoxes, theories and myths, of left-handed lore. Chock full of facts and fiction, it’s a book to be read with both hands.

Brain asymmetry for speech is moderately related to handedness but what are the rules? Are symmetries for hand and brain associated with characteristics such as intelligence, motor skill, spatial reasoning or skill at sports? In this follow up to the influential Left, Right Hand and Brain (1985) Marian Annett draws on a working lifetime of research to help provide answers to crucial questions. Central to her argument is the Right Shift Theory - her original and innovative contribution to the field that seeks to explain the relationships between left-and right-handedness and left-and right-brain specialisation. The theory proposes that handedness in humans and our non-human primate relations depends on chance but that chance is weighted towards right-handedness in most people by an agent of right-hemisphere disadvantage. It argues for the existence of a single gene for right shift (RS+) that evolved in humans to aid the growth of speech in the left hemisphere of the brain. The Right Shift Theory has possible implications for a wide range of questions about human abilities and disabilities, including verbal and non verbal intelligence, educational progress and dyslexia, spatial reasoning, sporting skills and mental illness. It continues to be at the cutting edge of research, solving problems and generating new avenues of investigation - most recently the surprising idea that a mutant RS+ gene might be involved in the causes of schizophrenia and autism. Handedness and Brain Asymmetry will make fascinating reading for students and researchers in psychology and neurology, educationalists, and anyone with a keen interest in why people have different talents and weaknesses.

This volume adds new dimension and organization to the literature of touch and the hand, covering a diversity of topics surrounding the perception and cognition of touch in relation to the hand. No animal species compare to humans with regard to the haptic (or touch) sense, so unlike visual or auditory cognition, we know little about such haptic cognition. We do know that motor skills play a major role in haptics, but senses like vision do not determine hand preference or hand ability. It seems also that the potential ability to perform a task may be present in both hands and evidence indicates that the hand used to perform tactile tasks in blind or in sighted conditions is independent of one’s hand preference. This book will be useful for those in education and robotics and can serve as a general text focusing on touch and developmental psychology.

Neural Plasticity Across the Lifespan reviews the recent scientific developments which are transforming our understanding of the human brain. For many years it was thought that modifications to the structural and functional organization of the brain were limited to a short early period of life, "the critical period", and, in adults, to the memory system. Recent research suggests that on the contrary we should see the human brain as a flexible structure, which adapts and modifies in response to learning, sensory experience, age and disease. The book provides an integrated overview of contemporary research on neural plasticity - the process by which the brain can change in structure and function to cope with new experiences and react to the effects of acquired damage or sensory deprivation. It reviews data on plasticity in the developing brain, looking at both typical and atypical development, alongside clinical and observational research on the adult population. It covers a number of key topics, including: different forms of neural plasticity factors affecting neural plasticity (ageing and gender), neural plasticity in language acquisition, memory and bodily self-consciousness mechanisms of repair – plasticity following sensory deprivation and acquired brain damage. This is an accessible overview of an emerging field of research which has fundamental implications for how we perceive our potential to change throughout our lives. It will be essential reading for all students of cognitive development, cognitive neuroscience and lifespan development.