Medical Education


Handedness and Lateralisation

For a full list of publications on handedness and asymmetry, please click here.

Resources for studying handedness, in particular questionnaires, are available, including handedness questionnaires and a variant of Tapley and Bryden's circle marking task for performance differences between the hands.

I have been studying handedness, lateralisation and asymmetry since I was an undergraduate, when I published two papers on how painted portraits are more likely to show their left cheek than their right, and how Rembrandt used the right cheek more often in his self-portraits and in portraits of his male and female kin. Chapters 13 and 14 of my PhD thesis followed up these questions, and they were also reviewed in a 2005 paper. My interest in asymmetries in art also resulted in a now notorious paper entitled 'Scrotal asymmetry in man and in ancient sculpture', for which in 2002 I was awarded an Ig Nobel prize. The topic was also discussed in more detail in chapter 12 of my PhD thesis, that chapter also eventually being published in 2004.

Drawing of hand by Anna McManus
Genetic models of handedness and cerebral lateralisation. My PhD mainly concerned genetic models of handedness and cerebral lateralisation (see chapters 7 and 8). Click here for the monograph that describes the genetic model that was first presented in my PhD thesis. More technical reviews of the issues can be found in a chapter contributed to the 1990 Ciba Symposium on lateralisation, or to the 1992 chapter in the Handbook of Developmental Psychology.  If you are looking for a very brief answer to the question, "Why are some left-handed and others right-handed?", then a good start may be the answer that New Scientist asked me to provide for its Last Word section.  

Right Hand, Left Hand. In 2002 I published a popular science book called Right Hand, Left Hand which discussed right-left asymmetries from a very broad perspective, looking not only at right and left-handedness in their everyday sense, but also at brain asymmetry, bodily asymmetries, asymmetries in biochemistry, chemistry and physics, the philosophical problems underlying asymmetry, and the social, cultural and anthropological meanings which are attached to right and left, as well as the surprisingly complex issues surrounding the side of the road on which countries choose to drive. The website for Right Hand, Left Hand also has a number of tests and questionnaires which can be completed, the data from which are being used in various research projects.

Philip Ball described the book in the Financial Times, in 2009, as:

"Everything you could want to know about why left-right symmetry exists and what it means in nature, in humans, in art and in culture.  It is one of those books that isn't afraid to venture wherever the topic takes us, whether that is the origin of life, Billy the Kid or Thomas Mann's Magic Mountain. It's my favourite sort of science book, in which the science is just a launching pad for excursions into all kinds of wild and wonderful terrain."

The Right Hand and the Left Hand of History.  This special issue of Laterality is devoted to eight papers covering a wide range of issues concerned with right, left and asymmetry in historical contexts.  Click here for more information. 
Primary Ciliary Dyskinesia. Primary Ciliary Dyskinesia (PCD) is a congenital condition, previously known as Kartagener's Syndrome or Siewert's Syndrome or Immotile Cilia Syndrome, in which the cilia do not beat or beat ineffectually. The result is a cluster of symptoms including bronchiectasis and chronic sinusitis, there is sometimes reduced fertility, and, in about half of the cases, there is situs inversus, the left-right reversal of body organs, most obviously with the heart being on the right side of the chest.We have published a series of papers on PCD including a study of the respiratory and other problems reported by patients, the effects of stigma and personality on symptoms, and the handedness and lateralisation of individuals with PCD.