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.

part I|20 pages


part II|86 pages

The Right Shift Theory

chapter 2|25 pages

Human Handedness

Discrete Types or Continuous Varieties?

chapter 3|24 pages

The Right Shift Theory of Handedness

Chance Plus or Minus Right Loading

chapter 5|14 pages

The Single Gene Theory of Right Shift

part III|76 pages

Explorations in the Light of the Theory

chapter 6|13 pages

Stability and Change

Handedness with Age, Sex and Time

chapter 8|21 pages

Other Asymmetries of Brain and Behaviour

part IV|98 pages

A Genetic Balanced Polymorphism with Heterozygote Advantage

chapter 10|18 pages

Why Right Shift and Why Genetic Variability?

The Advantages and Disadvantages of the RS + Gene

chapter 11|14 pages

Heterozygote Advantage

chapter 12|20 pages

What are the Disadvantages of Right Shift?

Spatial and Mathematical Reasoning, Art, Music, Surgery and Sport

chapter 13|24 pages

Speech, Phonology and Varieties of Dyslexia

The Costs and Benefits of the RS + Gene

chapter 14|20 pages

Schizophrenia and Autism

The Theory of an Agnosic RS + Gene

part V|29 pages

Independent Replications, Challenges and Theories

chapter 15|11 pages

Independent Tests and Challenges

part VI|16 pages


chapter 17|14 pages


What, How and Why?