The Many Sides of Asymmetry

Abstract

Right Hand, Left Hand: Origins of Asymmetry in Brains, Bodies, Atoms, and Cultures. Chris McManus. Cambridge: Harvard University Press. 2002; 432 pp. In an age when popular science books seem to be written about just about anything-there are several currently circulating, for instance, on the topic of coffee, and two on the role of cod in world history-we have here an entry that discusses an apparently idiosyncratic and potentially trivial topic: of various kinds. It is also a book that ranges widely across normal disciplinary boundaries, as suggested by the book's subtitle: The origins of asymmetry in brains, bodies, atoms and cultures. It turns out that or asymmetry can be found in phenomena ranging from the smallest to largest scales of organization. We are told of left-handed sub-atomic particles such as neutrinos, left-handed amino-acids, the left-sided heart, and our lateralized brains, in which language abilities are usually found in the left hemisphere. book's author, Chris McManus, a professor of Psychology and Medical Education at University College London, is someone who admits to a nearly lifelong obsession with this topic. This isn't surprising, since it would take a life-time to acquire the expertise necessary to cover the range of topics so lucidly conveyed in this book. McManus really covers a lot of ground, and the book makes for a fascinating read. One can't help but learn some new things and gain new perspectives. McManus also has a real passion for his subject, making for some lively prose, with fascinating anecdotes. But it was winning a prize for popular science writing in a contest sponsored by a British medical trust that put the idea of writing the book into the author's head. Given that no one but McManus is likely to be expert in all the areas he covers, it's just as well that he deals with each topic presuming little background. But why should anyone really be interested in so arcane a subject as symmetry? Is this book simply something one picks up to flip through, looking for that juicy tidbit to impress listeners at the next cocktail party? Handedness or symmetry, after all, is not something that is regularly advertised in academic job descriptions as an area of expertise, so one need not read this to catch up on some well-recognized area of research. One might wonder, in particular, why should an anthropologist read a volume like this? Much of what the book covers falls into the domains of other sciences like physics and biology. But the book's title mentions asymmetries in culture, and several chapters are devoted to analyzing cultural topics. For example, McManus provides explanations for why some countries drive on the left, and why some scripts move from left to (e.g., English), while others are written in the opposite direction (e.g., Hebrew). These phenomena are basically just social conventions, sometimes acquired by transmission from other groups, so no universal principle is at work here (which is why there are examples of both kinds of rules in each case). But other features of culture and society are not so variable. In fact, there is, McManus argues, a universal symbolic association of with good and left with bad. For example, he provides lists from Aristotle (derived from established by the Pythagoreans) and a variety of cultural groups (such as the Gogo of Tanzania) that can be compiled to produce a compelling world-view based on this simple dichotomy: IMAGE FORMULA7IMAGE FORMULA8 Lots of rituals must go in clock-wise progression as well, McManus notes (just think of passing food around a table). Religions are full of symbolic asymmetries. Bible refers to the right hand of God, for instance. Such universal principles beg for explanation, not just cataloguing, McManus argues. But there is no universal theory of symbolism, and so no way to make sense of this apparently universal tendency to equate handedness with other traits. …