In lieu of an abstract, here is a brief excerpt of the content:

Reviewed by:
  • Human language and our reptilian brain: The subcortical bases of speech, syntax, and thought by Philip Lieberman
  • Jean Aitchison
Human language and our reptilian brain: The subcortical bases of speech, syntax, and thought. By Philip Lieberman. Cambridge MA: Harvard University Press

Almost all attempts to account for the neural bases and evolution of language have looked to the neocortex, which is the most recent evolutionary aspect of the mammalian brain, Philip Lieberman points out. The neocortex must of course be included, but ‘some of the key structures of the FLS [functional language system] are subcortical basal ganglia—our reptilian brain’ (1), which, in concert with other structures of the brain, may, he asserts ‘be the key to human language and cognition’ (1). This claim is clarified and expanded in the course of the book. The material included is both a summary of, and an advance on previous work by L (e.g. Lieberman 1984, 1991, 1998). A key premise is that language is not an instinct. Instead, ‘it is a learned skill, based on a functional language system that is distributed over many parts of the human brain’ (1).

In a somewhat belligerent introduction, L castigates those who maintain ‘modular’ theories of mind and calls for ‘a new era of biological linguistics’ (17). The book ‘proper’ contains six chapters. Ch. 1 presents a brief overview of the brain, with an outline account of some recent noninvasive methods for studying it. Ch. 2 documents information on the production and perception of speech and draws attention to work (some quite old) which emphasizes the intimate relationship between the two. Ch. 3 outlines the lexicon and working memory: The brain’s dictionary, he suggests, ‘appears to be instantiated by means of a distributed network in which neuroanatomical structures that play a part in the immediate perception of objects and animals as we view them or the gestures associated with tools as we use them are activated’ (81). The lexicon is plastic and shaped by life’s experiences, he points out, in that it connects real-world knowledge with the sound patterns found in words. Humans possess a verbal working memory which ‘appears to be instantiated in the human brain by a dynamic distributed network that recruits neural “computational” resources in response to task demands’ (81). The neural network that is the basis of verbal working memory links activity in posterior temporal regions of the neocortex with frontal regions, and subcortical structures are also implicated.

Ch. 4, ‘The subcortical basal ganglia’, is the core of the book and its most novel and interesting chapter. In it, L explains how recent work has suggested a greater involvement of subcortical [End Page 837] structures in many cognitive processes, including working memory, rule-based learning, and the planning of future behavior: The basal ganglia in particular appear to play a key role in sequencing, including (in humans) learned voluntary sequences. Accordingly, L provides labelled diagrams of the main subcortical structures and discusses the possible organization of some basal ganglia circuits.

Ch. 5 discusses the evolution of the FLS. Lexical ability and the ability to comprehend simple aspects of syntax can be observed in living apes, he notes. In contrast, the ability to produce novel sound sequences that signal words appears to be the product of species-specific attributes of the human brain. This human capacity may reflect subcortical basal ganglia functions. He argues that Neanderthals did not have a human supralaryngeal vocal tract (SVT) and could not produce the full range of human speech sounds. This was pointed out in Lieberman et al. 1972, a paper sometimes cited to support the position that speech and language were absent in Neanderthals. But, as L points out, limits on phonetic ability do not necessarily signify the complete absence of speech and language.

Finally, L argues for a link between walking and talking: ‘the demands of bipedal locomotion may have selected for the evolution of enhanced subcortical motor control structures (basal ganglia and cerebellum) that regulate walking’ (151). In short, ‘speech communication can be regarded as a biological extension of upright posture’s freeing hominid hands for work’ (151).

Three aspects of this book are of particular interest...

pdf

Share