Home | Business News | Browse by Publication | A | Archaeology in Oceania

Clothing and modern human behaviour: prehistoric Tasmania as a case study.

Article Excerpt
Abstract

A general model is outlined showing how the prehistoric development of clothing for thermal reasons may be relevant to the emergence of modern human behaviour. A distinction is drawn between simple and complex clothing, with the latter leading to repercussions that can ultimately became decoupled from thermal contingencies. Archaeological correlates of complex clothing can be linked to attributes of modern human behaviour, some but not all of which made a transient appearance in late Pleistocene Tasmania. Cave sites in the southwest of the island have yielded bone tools and distinctive stone scraper tools, along with evidence for the targeting of prey species and parietal artworks in some caves. Thermal conditions in late Pleistocene Tasmania approached the known limits of human cold tolerance, necessitating the use of clothing. The archaeological record is reviewed in relation to likely technological and other correlates of the manufacture of clothing. It is argued that thermal parameters were a significant aspect of the human response to climate change in Tasmania. These developments invite comparison with those witnessed outside the region during the Upper and late Middle Pleistocene, particularly in northern middle latitudes and also in Africa, where they are interpreted as indicating the emergence of modern human behaviour.

Keywords: Clothing, Tasmania, human cold tolerance

**********

This paper explores links between the development of clothing and behavioural modernity and, as a case study, examines archaeological evidence for human responses to changing thermal conditions during and after the last ice age in Tasmania. It begins with a brief outline of the main issues in thermal physiology and their relevance to prehistoric humans. The focus is on the limits of cold tolerance, and how clothing functions to provide thermal insulation. Protection from wind chill is the most important aspect, and wind chill levels in Tasmania approached these limits during the late Pleistocene. If clothing was required, no direct evidence of such garments has survived, but the archaeological record can be examined for indirect evidence of clothing. The Tasmanian developments are then considered in relation to trends seen elsewhere across the Pleistocene/Holocene boundary. An 'insular' model based on thermal principles is outlined, linking environmental and human behavioural change in this crucial period based on the correlates and repercussions of clothing. Some background material is briefly covered, such as thermal and clothing physiology and details of palaeoenvironmental reconstructions. More extensive treatments are available in Gilligan (2007, in press a). A key assumption is that the origin and development of clothing prior to the Holocene was predicated largely if not exclusively on human thermal needs (see Gilligan Submitted).

Thermal physiology

The principles and experimental findings relating to human responses to varying thermal conditions have been well documented (e.g. Jessen 2001; Parsons 2003:293-325). The optimal ambient temperature for lightly-clothed people is 25 [degrees] C (Fanger 1970:130-131), and shivering begins at around 13 [degrees] C. The chilling effect of wind is evident in the wind-chill index (Steadman 1995). Reports of accidental exposure demonstrate how hypothermia can lead rapidly to death (e.g. Collins 1983; Tanaka and Tokudome 1991).

Cold tolerance is improved through acclimatisation (e.g. Bodley 1978), and routinely unclothed populations such as the Australian Aborigines show superior cold responses (e.g. Hicks et al. 1931; Scholander et al. 1958), but these improved defences are 'of little use during intense and continuous exposure' (Jessen 2001:152). Humans can adapt to cold, but only down to a 'critical level' below which hypothermia begins within hours (Hensel 1981:220). Published findings suggest that the safe limit for modern-day humans, beyond which the risk of hypothermia can become acute, occurs at a still-air temperature of approximately -1 [degrees] C. For habitually unclothed humans, tolerance extends to around -5 [degrees] C. While the extent of cold tolerance among some indigenous peoples such as those of Tierra del Fuego at the southern tip of South America is surprising (e.g. Darwin 1839:234-5), their behavioural cold adaptations included shelters made from tree branches, guanaco pelts and seal skins, and they also utilised sealskin capes and long robes of woolly guanaco skins.

Clothing physiology

The thermal insulating properties of clothing are detailed in various studies of clothing physiology (e.g. Siple 1945; Newburgh 1949; Burton and Edholm 1955:58; Fourt and Hollies 1970; Hensel 1981; Watkins 1984). In essence, clothing functions as thermal insulation by trapping air in layers and in tiny pockets close to the skin surface, reducing the thermal gradient between the body and the external environment. The effective thermal resistance of clothing is indicated by the 'clo' unit (Gagge et al. 1941:429). Generally, each extra layer of clothing adds nearly 1 clo: donning an overcoat provides about 2 clo of insulation, while Arctic clothing (4 layers) provides about 4 clo of thermal protection (Sloan 1979:17). However, the utility of clo units for pre-Holocene clothing is limited, for two reasons. First, the measures are derived from modern-day tailored garments manufactured from woven fibres, the thermal qualities of which are quite different from those of prepared animal hides and furs. Second, clo units apply to wind-free conditions, and so may give a misleading impression of the protective value at colder wind chill levels, especially where prehistoric garments may have been draped rather than fitted.

Simple vs. complex clothes

I make a distinction between what I term 'simple' versus 'complex' clothing (Table 1). This is based on physiological principles but it also has important archaeological implications. The physiological distinction arises from two aspects that largely determine the thermal effectiveness of clothing. First, whether a garment is properly 'fitted', i.e. shaped to fit closely around the body, including the limbs, as opposed to being loosely draped over the body, leaving the limbs less protected. The second aspect is the number of layers of garments, with multiple layers requiring that at least the inner layer(s) are fitted. Or, put another way, if only draped garments are in use, practical considerations will mean that such clothing is generally restricted to a single layer....

View this article FREE - Now for a Limited Time, try Goliath Business News
Free for 3 Days!