Elsbeth Stern weighs up two studies probing the idea of the brain as the body's servant.
Intelligence in the Flesh: Why Your Mind Needs Your Body Much More Than it Thinks
By Guy Claxton
Prehension: The Hand and the Emergence of Humanity
By Colin McGinn
How has Homo sapiens uncovered the laws of nature, invented technology and established culture and institutions? Most scientists' answers to that question have been top-heavy, referring to language, symbolic reasoning and consciousness as unique human abilities on which comprehension, analysis, abstraction and reasoning are based. Since the 1950s, those abilities have increasingly become a focal point for psychological research. Encouraged by progress in informatics, researchers began to create digital models of the processes by which sensory input is selected by the brain, stored in the memory, connected to existing knowledge and used for elaboration. These 'cognitive architectures' were supposed to simulate and predict learning, reasoning, complex problem-solving and decision-making.
This algorithmic focus on mental activities ignores the fact that human beings engage with evolutionary pressures using their entire bodies — a point explored by psychologist Guy Claxton in Intelligence in the Flesh, and by philosopher Colin McGinn in Prehension.
Intelligence in the Flesh deals with the unity of mind, brain and body in human information-processing, including higher cognition and academic learning. Claxton argues that humans would think and behave differently if their physiological functioning were different. For instance, there is research that shows how holding a cup of hot coffee or receiving other sensory input through the skin can influence judgement and decision-making (L. E. Williams and J. A. Bargh Science 322, 606–607; 2008), a fact entirely ignored in cognitive theories that confine themselves to visual and auditory input. The brain coordinates information, but it is the “servant, not master of the body”, notes Claxton.
McGinn's focus in Prehension is the human hand. He is not the first to emphasize that thanks to their bipedal gait, early humans did not need their 'forepaws' for locomotion, freeing them to manipulate the environment with the help of tools. However, McGinn goes further, positing that the multiple opportunities provided by our hands shape our concepts of the mind. Therefore we conceive cognitive processes in manual terms, such as 'grasping an idea'.
Claxton and McGinn value higher-order cognition and academic learning differently. McGinn argues that the close interaction between brain and hand allowed humans to find their evolutionary niche through the discovery of physical tools, as well as mental ones such as language or mathematical symbols. He claims that using the hands for pointing and communicating resembles 'air writing', and thereby facilitated the invention of script. Claxton, by contrast, thinks that cognitive competencies based on symbolic systems such as writing (which he pejoratively labels “Cartesian education” in reference to philosopher René Descartes's idea of mind–body dualism) are overvalued, whereas handicrafts and vocational education are undervalued. A strong focus on academic learning and abstract reasoning does not meet the needs of the majority, he argues — to the point that this form of intelligence is essentially alien to humans. Meanwhile, McGinn posits that it is why our otherwise sparsely equipped species has survived.
There is a bullish flavour to their modes of argument that shows that Claxton and McGinn are aware of how controversial their claims are. In fact, how new and robust is the science in each book? Criticism of the shortcomings of cognitive architectures is no novelty. Since the 1980s, the evolutionary aspects of human behaviour and cognition have become a seminal topic throughout psychology. It is widely acknowledged that humans are challenged by the fact that we are adapted to the world as it existed more than 30,000 years ago. It is fully accepted that we are born endowed with perceptual and behavioural programs that were adaptive for our earliest ancestors and that still affect our behaviour, information-processing and emotional functioning. So when criticizing a Cartesian view of human learning, the authors are preaching to the converted.
Both books are slippery in their dealings with state-of-the-art research. McGinn almost entirely ignores empirical psychology research and instead provides evidence based mostly on plausibility — for instance, when he claims that humans have privileged access to geometry because they can form circles and triangles with their fingers. There is prominent research confirming his emphasis on the pivotal role of hand–brain interaction in human cognition, including dozens of studies on the importance of gesturing in learning. Psychologist Susan Goldin-Meadow's Hearing Gesture (Harvard University Press, 2003) is one. McGinn also refers to the views of developmental psychologist Jean Piaget regarding sensorimotor activity as the foundation of cognition in early child development. Yet for more than 30 years, psychologists have shown that the brains of newborns are endowed with core knowledge that prepares them to represent information about objects, quantities and actions long before they can grasp with their hands.
Claxton cherry-picks from psychology and neuroscience literature. When he attacks conventional school education, he provides anecdotal evidence about unhappy children, but ignores evidence-based attempts to improve schooling — for instance, by bringing everyday experience into the teaching of science and mathematics. Claxton's claim that performance in intelligence tests is unrelated to factors important in real life is not reflected in state-of-the-art research, such as the more than 100 publications based on studies of the Lothian Birth Cohort, headed by psychologist Ian Deary of the University of Edinburgh, UK. Intelligence, Deary has shown, is not only significantly related to educational and professional outcome, but is also a factor in positive well-being, health and longevity.
Intelligence in the Flesh and Prehension are eloquently written, refreshing and entertaining. But Claxton and McGinn fight many straw men, and often fail to provide evidence for provocative statements.