Search Results

The Experience of Left and Right

Geoffrey Lee

in Perceptual Experience

This chapter explores the idea of ‘left—right phenomenal inversion’ and its relationship to the symmetries of the human body. Roughly, a subject is phenomenally left—right inverted with respect to ... More

This chapter explores the idea of ‘left—right phenomenal inversion’ and its relationship to the symmetries of the human body. Roughly, a subject is phenomenally left—right inverted with respect to you, if the way the world appears to them in experience is the way it would appear to you, were you placed in a counterpart of the physical world where everything external to your body was macroscopically arranged in a mirror image of its actual arrangement. It is argued that given certain assumptions, a subject who began life as a physical mirror-image counterpart of you would have experiences that were phenomenally left—right inverted with respect to yours. A surprising corollary of the argument is that a subject who started life in a physically symmetrical state would not have experiences that distinguished between an asymmetrical stimulus and the mirror-image counterpart of the stimulus.Less

Sex Differences in Human Behavior

Melissa Hines

in Brain Gender

This chapter begins with a discussion of the meaning of sex difference. It then considers conflicts arising from measurements of psychological sex differences. Sex differences in core gender identity ... More

This chapter begins with a discussion of the meaning of sex difference. It then considers conflicts arising from measurements of psychological sex differences. Sex differences in core gender identity and sexual orientation, cognition, aggression, play, handedness and language lateralization are discussed.Less

Cognitive-Motor Skills

Kenneth M. Heilman

in Matter of Mind: A Neurologist's View of Brain-Behavior Relationships

This chapter discusses the brain mechanisms that underlie cognitive motor skills. Topics covered include movement memories or representations, praxis and handedness, and mechanical knowledge. To ... More

This chapter discusses the brain mechanisms that underlie cognitive motor skills. Topics covered include movement memories or representations, praxis and handedness, and mechanical knowledge. To perform skilled acts (praxis), people need movement programs and mechanical knowledge. Movement, or praxis, programs are the instructions given to the nerves that control the limbs. These programs instruct the muscles about what joint or joints to move, in which direction, at what time, with what speed, and with how much force. Studies of patients with hemispheric injuries provide evidence for left hemisphere praxis dominance in right-handed people and right hemisphere praxis dominance in left-handed people. Studies also demonstrate that mechanical knowledge is stored independently of other forms of knowledge, such as movement programs and language.Less

 Directions, hands, and charges

Frank Arntzenius

in Space, Time, and Stuff

This chapter develops an idea of Richard Feynman’s, namely the idea that anti-particles are nothing but particles travelling back in time, and the related idea that what is standardly called the CPT ... More

This chapter develops an idea of Richard Feynman’s, namely the idea that anti-particles are nothing but particles travelling back in time, and the related idea that what is standardly called the CPT theorem is really a theorem which shows that space-time has neither a direction in time nor a spatial handedness structure.Less

Brain Asymmetry in Vertebrates

Onur Güntürkün

in How Animals See the World: Comparative Behavior, Biology, and Evolution of Vision

Until the 1970s, cerebral asymmetries were thought to be unique to humans. However, left-right differences of brain and function are not only widespread among mammals, but also among many other ... More

Until the 1970s, cerebral asymmetries were thought to be unique to humans. However, left-right differences of brain and function are not only widespread among mammals, but also among many other vertebrates. Thus, cerebral asymmetry is a ubiquitous phenomenon that possibly is not the exception, but the rule. Brain asymmetries deeply affect the neural processes of vision at all levels of analysis. This chapter reviews animal asymmetries of handedness and vocalization, as well as visual asymmetries of features and space.Less

Evolutionary perspectives on sport and competition

Diana Wiedemann, Robert A Barton, and Russell A Hill

in Applied Evolutionary Psychology

This chapter examines the theoretical and empirical research into evolutionary aspects of four complex issues of human behaviour in sports. We highlight how evolutionary approaches have promoted our ... More

This chapter examines the theoretical and empirical research into evolutionary aspects of four complex issues of human behaviour in sports. We highlight how evolutionary approaches have promoted our understanding of human sports and competition. To begin with, we describe the relationship between sports competitions and testosterone levels and elucidate how winning and losing leads to different, sometimes status-changing, endocrine responses. Secondly, we look at ‘home advantage’ and examine how hormonal and psychological research has aided our understanding of this well-known phenomenon. The next section focuses on possible evolutionary explanations as to why left-handers may have an advantage in physical combat in both traditional and westernized societies. The final section examines colour influences on human behaviour in general and on sports competition in particular, focusing specifically on the significance of the colour red in human competitive interactions. These four themes serve to highlight the value of evolutionary approaches in enhancing and enriching our understanding of human sports competitions.Less

Objects

Barbara Landau and James E. Hoffman

in Spatial Representation: From Gene to Mind

People with WS display severe deficits in visual copying tasks such as block construction. This deficit is not related to problems with early visual processes such as acuity or stereoscopic vision ... More

People with WS display severe deficits in visual copying tasks such as block construction. This deficit is not related to problems with early visual processes such as acuity or stereoscopic vision or with mid-level visual functions such as perceptual grouping. Moreover, many higher-level visual functions such as object recognition or face processing are intact. However, people with WS do have difficulty recognizing objects from unusual viewpoints and discriminating objects from their mirror images. The general pattern of strengths and weaknesses is consistent with the hypothesis of a spatial deficit focused on the dorsal stream, as discussed in Chapter 2. But perhaps more revealing, for most spatial functions we discuss, people with WS perform remarkably like much younger normally developing children, both quantitatively and qualitatively. The chapter closes by hinting at a new hypothesis: That people with WS show strength for those functions normally acquired early, and weakness for those normally acquired over a protracted developmental timeline.Less

Simpson’s paradox—two examples and a bit more

Steve Selvin

in The Joy of Statistics: A Treasury of Elementary Statistical Tools and their Applications

When data that are not homogeneous are combined they often produce a variety of results that are deceptive and likely useless. Discussions and examples illustrate.

Handedness, cerebral lateralization, and the evolution of language

I. C. McManus

in The Descent of Mind: Psychological Perspectives on Hominid Evolution

Paul Broca observed that in a series of patients with aphasia, a condition which causes a loss of language, there was a concomitant paralysis of the right side of the body. At first it was often ... More

Paul Broca observed that in a series of patients with aphasia, a condition which causes a loss of language, there was a concomitant paralysis of the right side of the body. At first it was often assumed that these individuals were left-handed — in effect restoring some form of conceptual symmetry to an otherwise asymmetric brain. The precise nature of hemispheric specialisation is still far from clear, and is complicated by a number of observations. A complete and adequate theory of cerebral lateralisation must not only explain how and why language is typically located in the left hemisphere and visuo-spatial processing of complex images is typically located in the right hemisphere. The chapter adds that the so-called HERA model, hemispheric encoding/retrieval asymmetry, poses many problems for neuropsychology and, given the importance of semantic memory in language usage, those questions are likely also to be important for understanding the evolution of language. In addition, the chapter discusses the nature of handedness.Less

Cerebral dominance

Richard Passingham

in What is special about the human brain?

Different trends are observed in humans and chimpanzees when it comes to the subject of right or left hand dominance. Chimpanzees typically use their right hand for ballistic movements and their left ... More

Different trends are observed in humans and chimpanzees when it comes to the subject of right or left hand dominance. Chimpanzees typically use their right hand for ballistic movements and their left hand for other skilled actions. Humans, on the other hand, generally make use of their dominant hand the majority of the time. Moreover, handedness in humans helps determines which hemisphere of the brain is more involved in cerebral dominance for language. Several studies have also shown that handedness and language dominance are unique capabilities of the human brain. This chapter examines the relationship between the handedness of apes and the anatomical cerebral asymmetry of their brain. The available pieces of evidence which support the functional specialization of the left and right hemispheres of the human brain are also explored in this chapter. Furthermore, this chapter inquires into whether the existence of such specialization is possible in other primates.Less

Right hands

Ann Oakley

in Fracture: Adventures of a broken body

The links between language, brain asymmetry and right-handedness are said to be much of what makes a person human. Hands perform around a thousand different functions every day. The well-behaved hand ... More

The links between language, brain asymmetry and right-handedness are said to be much of what makes a person human. Hands perform around a thousand different functions every day. The well-behaved hand is an orchestra: when it plays, there's an extraordinary co-ordination of motor and sensory activities. The hand is both metaphor and symbol: a ‘short-hand’ version of one's self. As hands express one's genes and identities, they've acquired many different cultural functions. This chapter illustrates the author's fascination with the symbolism of the hand, with its differentiation into left and right, and the secret lateralisations of physics and chemistry, as part of her own quest to find out what's so wrong about having a damaged right hand.Less

Apraxia in left-handers

in Apraxia: The Cognitive side of motor control

In typical right-handers apraxia is predominantly bound to left-hemisphere lesions. This lateralization corresponds with that of language and that of motor control of the dominant hand. In ... More

In typical right-handers apraxia is predominantly bound to left-hemisphere lesions. This lateralization corresponds with that of language and that of motor control of the dominant hand. In left-handers the right hand is by definition in control of the dominant hand but lateralization of language can vary and is indeed more frequently in the left than in the right hemisphere. This situation raises the opportunity to probe which of the two associations in the typical brain is more important for the lateralization of apraxia. A study of consecutive left-handed patients with unilateral lesions revealed that the probability of defective pantomime is higher in patients with aphasia, and that of defective imitation higher in patients with right-hemisphere lesions and hemineglect, but that neither of these associations is mandatory. The laterality of lesions causing apraxia can dissociate both from aphasia and from handedness.Less

Sex Differences in Handedness, Brain Asymmetry, and Language Lateralization

Iris E. C. Sommer

in The Two Halves of the Brain: Information Processing in the Cerebral Hemispheres

This chapter offers an updated review and meta-analysis of existing research on sex differences, coupled with a thorough discussion of a possible underlying mechanism in a more bilateral brain in ... More

This chapter offers an updated review and meta-analysis of existing research on sex differences, coupled with a thorough discussion of a possible underlying mechanism in a more bilateral brain in females. It specifically discusses the current literature on sex differences in language lateralization as reflected in handedness, asymmetry of the planum temporale, and functional language lateralization. The chapter shows that cultural (or possibly racial) differences are a moderator of the sex difference in handedness. There is no sex difference in language lateralization. It is suggested that females who are innately left or mixed handed more frequently switch to right-hand use for social activities such as writing and eating than do left or mixed-handed males.Less

Handedness and Cerebral Asymmetry: An Evolutionary Perspective

Michael C. Corballis

in The Two Halves of the Brain: Information Processing in the Cerebral Hemispheres

This chapter concentrates on the evolutionary origin of hemispheric asymmetry, addressing manual dexterity and language. It investigates the possible evolutionary and genetic sources of the ... More

This chapter concentrates on the evolutionary origin of hemispheric asymmetry, addressing manual dexterity and language. It investigates the possible evolutionary and genetic sources of the asymmetries in the human brain. The chapter shows that the link between language and handedness is affirmed by evidence that language itself has strong connections to manual activity, and also reveals that FOXP2 may well play a role in the development of speech. Handedness and cerebral asymmetry may appear to defy the overall bilateral symmetry of living organisms. The chapter suggests that humans are distinctive among species in their ability to manipulate the physical and biological environment.Less

Structural Indices of Asymmetry

Katrin Amunts

in The Two Halves of the Brain: Information Processing in the Cerebral Hemispheres

This chapter summarizes the structural brain imaging results. It demonstrates that structural asymmetries are to be found in many, perhaps all, other brain regions (e.g. visual cortex, parietal ... More

This chapter summarizes the structural brain imaging results. It demonstrates that structural asymmetries are to be found in many, perhaps all, other brain regions (e.g. visual cortex, parietal cortex, hippocampus); that such previously thought to be static differences are subject to dynamic modulation through environmental influences; and that the degree of asymmetry differs with respect to brain region, handedness, gender, and disease. The chapter shows that the aymmetrical receptor binding differed between genders in the triangular part of the inferior frontal gyrus, and also, that asymmetry interferes with extrinsic and genetic factors, and changes during development and aging. It is found that asymmetry develops in the early stages of evolution and during ontogeny. Anatomical asymmetry and lateralization also interact.Less

Complex Media

G. F. Roach, I. G. Stratis, and A. N. Yannacopoulos

in Mathematical Analysis of Deterministic and Stochastic Problems in Complex Media Electromagnetics

This chapter discusses complex media, which plays a big part in the late-twentieth-century technology revolution and is propagating with increasing speed and expanding front. Complex media are ... More

This chapter discusses complex media, which plays a big part in the late-twentieth-century technology revolution and is propagating with increasing speed and expanding front. Complex media are artificial materials exhibiting properties, based on their structure rather than their composition, which are superior to those in naturally existing materials. Nevertheless, there certainly do exist materials in nature displaying ‘exotic’ properties. Moreover, a discrimination between left and right has proven to be a fertile concept in the many branches of science that feed into electromagnetics: handedness is a term that is used extensively in the complex media literature. There are actually three notions of handedness of interest in electromagnetics, as this chapter shows.Less

The biolinguistics of language universals:: The next years

Thomas G. Bever

in Language Down the Garden Path: The Cognitive and Biological Basis for Linguistic Structures

Bever reviews how his research program has evolved from the original assumption he made in 1970: that language is the result of genetic endowment, maturational processes, experience, and other ... More

Bever reviews how his research program has evolved from the original assumption he made in 1970: that language is the result of genetic endowment, maturational processes, experience, and other constraints. While statistical processes account for a lot of language development, there is still evidence for positing derivations in a model of language behavior. Bever considers that left-hemisphere priority for language may be based on its computational superiority, as opposed to its having a specific innate language creation mechanism. On the other hand, the emergence of “psychogrammar” may be the result of the need to have a consistent representation between the production and comprehension systems. The canonical sentence form in natural languages, he argues, may be a consequence of humans’ genetic predisposition to solve problems. Finally, Bever discusses future directions in his work: the importance of context when processing unclear speech signals and the genetic effects of familial left-handedness on language.Less

Differential Use of Dominant and Non-Dominant Hands: A Window on Referential and Non-Referential Functions

Nicla Rossini

in The Construal of Spatial Meaning: Windows into Conceptual Space

The study presented here contrasts ‘planning’ gestures (Kendon 2004) to referential gestures in map-task activities with blocked visibility. This topic has already been addressed in a number of ... More

The study presented here contrasts ‘planning’ gestures (Kendon 2004) to referential gestures in map-task activities with blocked visibility. This topic has already been addressed in a number of studies, with a variety of different interpretations of the communicativeness of gesture (see Wey 2006 for a review). Granted the dual function of gestures and language, i.e. that they can be both communicative and self-orientational (McNeill 2005), a new phenomenon is discussed, which has been observed under conditions of blocked visibility during route direction: participants tend to instantiate referential and self-orientational functions in different hands, so that the dominant hand tends to be devoted to referential aspects, while the weak hand engages in self-orientational functions and/or other psycho-pragmatic ones. This phenomenon is discussed within a theoretical framework that assumes both a communicative and self-orientational function for gestures.Less

Neural, Cognitive, and Anatomical Foundations

Lawrence Barham

in From Hand to Handle: The First Industrial Revolution

This chapter examines the neural, cognitive, and anatomical foundations of hafting, an innovation that took place in a technological world in which the hand holding tool served as the main interface ... More

This chapter examines the neural, cognitive, and anatomical foundations of hafting, an innovation that took place in a technological world in which the hand holding tool served as the main interface between the individual and the environment. More specifically, it shows how hafting enhanced the effectiveness of hand-held tools for cutting, scraping, chopping, and piercing. The chapter first describes the techniques of brain research and provides an overview of neural anatomy before turning to a discussion of brain areas that are likely to have been involved in the invention of hafting. It then considers which cognitive processes are needed to imagine and craft a hafted tool, along with the neural links between language and technology. It also analyses the archaeological evidence for handedness in order to understand the evolution of language as well as the ability to make complex tools and hold a handle.Less