Saturday, April 25, 2009

Part V: Other Theories of Language Origins in Hominids

While the discontinuity or innate theories of language origins tend to predominant in linguistic and psychological studies, there are several continuity or neoDarwinian theories which also deserve attention. These theories fall into three broad categories: cognitive enhancement, social intelligence, and manual gestures. As opposed to the theories which follow Chomsky’s model of identifying universal grammar and defining how a language acquisition device operates, and where it would be located, these continuity theories attempt to synthesize behavioural and environmental information to provide hypotheses of language origins. While the hypotheses of the discontinuity theory are tested using modern human children (i.e. Carstairs-McCarthy 1999; Dromi 1999; Berwick 1998) , continuity hypotheses tend to draw upon research conducted upon nonhuman primates (i.e. Dunbar 1998, 1996; Power 1998; Locke 1978).

Cognitive Enhancement

Dunbar’s (1998:94) social brain hypothesis proposes that the need to hold large highly structured hominid groups together was more important than the need to solve ecological problems. He (ibid.) proposes that in response to ecological pressures, hominid species were forced to evolve proportionately larger brains in order to allow large groups to remain stable. According to Donald (1998:57), modern human speakers often carry out several complex operations at once, in order to maintain “parity with the recipients of their communications”. Human language is thus characterized by its complexity, speed, and demands upon attention and working memory (ibid.). Cognitive enhancement theories state that as the brain evolved, it became capable of performing more complex tasks (Loritz 1999; Müller 1996; MacNeilage 1998; Locke 1997; Bradley 1995). These tasks were not necessarily ‘intentional’ but merely and offshoot of existing mental faculties incorporated into a new task. For example, the mental ‘lexicon’ of modern humans may simply be an enhanced ‘sound contex’ memory area, which would be found in nonhuman animals.

While most theories propose that a ‘protolanguage’ arose within the Homo erectus lineage (i.e. Locke 1998; Worden 1998; Arensburg 1994), a few assume that language is unique to modern humans (i.e. Lieberman and McCarthy 1999; Lieberman 1998; Noble and Davidson 1993). It has been proposed that a significant increment in human cognition resulted from the emergence of language (Mithen 1996; Noble 1996; Noble and Davidson 1989). This position lends itself to the assumption that it is implausible to suppose that cognition grew gradually over the approximately 2 mya of hominid development, but had virtually no effect on behaviour or technology. According to proponents of the discontinuity theories, if human cognition had gradually increased over time, we would expect to find that a slow but steady increase in the rate of technological and behavioural change left marks in the fossil record over the last million and a half years (Bickerton 1998; Mithen 1996, Noble 1996). Instead a long period of ‘stagnation’ was followed by a cognitive explosion occurring only after the appearance of anatomically modern humans in Europe approximately 50 kya (ibid.).

While it is tempting to point to Homo sapiens as being the intellectual giants of the hominid lineage, it is important to remember the following: 1) the fossil record is incomplete; and 2) due to taphonomic process, items such as stone tools tend to preserve for millions of years, whereas organic materials will decompose. These periods of intellectual ‘stagnation’ are due more to the lack of creative thinking on the part of those who study human evolution. It is akin to stating that there have been no technological, behavioural or intellectual changes in Homo sapiens based upon the production of ‘mud’ bricks, which hasn’t altered in over 8,000 years (Cavalli-Sforza 2000). A recent study by McBrearty and Brooks (2000) provides evidence that there was a gradual shift in both technology and behaviour during the Middle Stone Age period (approximately 300 kya) in Africa, which then spread to other parts of the Old World. According to McBrearty and Brooks (2000:4), the view that European Homo sapiens were responsible for ‘revolutionary’ advances in behaviour and technology is due to both Eurocentric bias and the lack of relevant fieldwork outside of Africa.

Social Intelligence: Theory of Mind

According to Locke (1998:197), the social sound making, talking and language evolved to serve the needs of individuals who were alike and knew each other. Thus the pressure to speak elaborately would have come from the need to monitor and share with others, the perceived intentions and actions of fellow members of the group (ibid.). Tomasello et. al. (1993:496-496) have proposed that language could only have emerged after hominids had evolved the social skills that are evident very early in modern human development, and that are the precursors of language. These skills include: theory of mind (understanding the intentionality of other minds), imitation and intentional expression.

It should be noted that: 1) intelligence is not one general ability that assists an organism in all situations (Gigerenzer 1997:271); 2) complex intellectual processes seem to be necessary for many social interactions (Tomasello and Call 1997:351); and 3) primates have a domain specific knowledge of the world. However this knowledge can be transferred or exchanged when there are changes in the environment (Gigerenzer 1997:274-275; Tomasello and Call 1997:353). Field observations of specific primate groups seems to indicate that they possess a complicated, social, intelligence for interacting with other group members (ibid.). Tomasello and Call (1997) suggest that in the wild nonhuman primates have the ability to understand the mental states of others, even though they have failed experimental studies of metacognition. The failure in the lab setting may be due to the fact that the experimental design was originally intended to test theory of mind in human children, and therefore rests upon verbal competence in order to succeed (Tomasello and Call 1997:362). With regard to language and theory of mind in modern humans, most communication does not necessitate any knowledge of the mental states or beliefs of others. For example, the observed behavioural response of a group of individuals to an ‘alarm’ call (i.e. someone yelling “Fire”) is not depended upon the caller having any awareness of the mental states of the other individuals.