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The presence of divergent and independent research traditions in the gestural and vocal domains of primate communication has resulted in major discrepancies in the definition and operationalization of cognitive concepts. However, in recent years, accumulating evidence from behavioural and neurobiological research has shown that both human and non-human primate communication is inherently multimodal. It is therefore timely to integrate the study of gestural and vocal communication. Herein, we review evidence demonstrating that there is no clear difference between primate gestures and vocalizations in the extent to which they show evidence for the presence of key language properties: intentionality, reference, iconicity and turn-taking. We also find high overlap in the neurobiological mechanisms producing primate gestures and vocalizations, as well as in ontogenetic flexibility. These findings confirm that human language had multimodal origins. Nonetheless, we note that in great apes, gestures seem to fulfil a carrying (i.e. predominantly informative) role in close-range communication, whereas the opposite holds for face-to-face interactions of humans. This suggests an evolutionary shift in the carrying role from the gestural to the vocal stream, and we explore this transition in the carrying modality. Finally, we suggest that future studies should focus on the links between complex communication, sociality and cooperative tendency to strengthen the study of language origins.

Early plant use is seldom described in the archaeological record because of poor preservation. We report the discovery of grass bedding used to create comfortable areas for sleeping and working by people who lived in Border Cave at least 200,000 years ago. Sheaves of grass belonging to the broad-leafed Panicoideae subfamily were placed near the back of the cave on ash layers that were often remnants of bedding burned for site maintenance. This strategy is one forerunner of more-complex behavior that is archaeologically discernible from ~100,000 years ago.

Middle Stone Age cooking Early evidence of cooked starchy plant food is sparse, yet the consumption of starchy roots is likely to have been a key innovation in the human diet. Wadley et al. report the identification of whole, charred rhizomes of plants of the genus Hypoxis from Border Cave, South Africa, dated up to 170,000 years ago. These archaeobotanical remains represent the earliest direct evidence for the cooking of underground storage organs. The edible Hypoxis rhizomes appear to have been cooked and consumed in the cave by the Middle Stone Age humans at the site. Hypoxis has a wide geographical distribution, suggesting that the rhizomes could have been a ready and reliable carbohydrate source for Homo sapiens in Africa, perhaps facilitating the mobility of human populations. Science , this issue p. 87

Using fire experiments, we investigate claims that black organic residues on lithics found in Stone Age sites are markers for heat treatment of rocks in the embers of aboveground wood fires. We buried sedges overlain with lithics and bone to replicate plant bedding sometimes found in archaeological sites. Small fires were lit over the material buried under a mixture of coarse- and medium-grained sand. Black carbonised residues formed on several lithics that were in direct contact with buried sedges that burned below the fire. FTIR, Raman and preliminary GC–MS measurements were made on dried and burnt sedge, burnt bone, and on a prominent black residue that formed on one quartz piece that had been in contact with buried fresh sedge when it was heated. Importantly, we were able to confirm the spontaneous and accidental transfer of organic compounds to lithics buried and heated underground in the presence of plant material. This means that carbonised organic residues are not useful markers for determining whether heat treatment of rocks took place above or below ground. Our preliminary experiments imply that further work should be done to investigate the causes of the residues formed on lithics underground.

The concept of functional reference has been used to isolate potentially referential vocal signals in animal communication. However, its relatedness to the phenomenon of reference in human language has recently been brought into question. While some researchers have suggested abandoning the concept of functional reference altogether, others advocate a revision of its definition to include contextual cues that play a role in signal production and perception. Empirical and theoretical work on functional reference has also put much emphasis on how the receiver understands the referential signal. However, reference, as defined in the linguistic literature, is an action of the producer, and therefore, any definition describing reference in non-human animals must also focus on the producer. To successfully determine whether a signal is used to refer, we suggest an approach from the field of pragmatics, taking a closer look at specific situations of signal production, specifically at the factors that influence the production of a signal by an individual. We define the concept of signaller's reference to identify intentional acts of reference produced by a signaller independently of the communicative modality, and illustrate it with a case study of the hoo vocalizations produced by wild chimpanzees during travel. This novel framework introduces an intentional approach to referentiality. It may therefore permit a closer comparison of human and non-human animal referential behaviour and underlying cognitive processes, allowing us to identify what may have emerged solely in the human lineage.

New excavations at Border Cave use high-resolution techniques, including FT-IR, for sediment samples and thin sections of micromorphology blocks from stratigraphy. These show that sediments have different moisture regimes, both spatially and chronologically. The site preserves desiccated grass bedding in multiple layers and they, along with seeds, rhizomes, and charcoal, provide a profile of palaeo-vegetation through time. A bushveld vegetation community is implied before 100,000 years ago. The density of lithics varies considerably through time, with high frequencies occurring before 100,000 years ago where a putative MSA 1/Pietersburg Industry was recovered. The highest percentage frequencies of blades and blade fragments were found here. In Members 1 BS and 1 WA, called Early Later Stone Age by Beaumont, we recovered large flakes from multifacial cores. Local rhyolite was the most common rock used for making stone tools, but siliceous minerals were popular in the upper members. Fil: Backwell, Lucinda Ruth. University of the Witwatersrand; Sudáfrica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina Fil: d'Errico, Francesco. Universite de Bordeaux; Francia. University of Bergen; Noruega Fil: Banks, William E.. Universite de Bordeaux; Francia Fil: de la Peña, Paloma. University of the Witwatersrand; Sudáfrica Fil: Sievers, Christine. University of the Witwatersrand; Sudáfrica Fil: Stratford, Dominic. University of the Witwatersrand; Sudáfrica Fil: Lennox, Sandra J.. University of the Witwatersrand; Sudáfrica Fil: Wojcieszak, Marine. University of the Witwatersrand; Sudáfrica Fil: Bordy, Emese M.. University Of Cape Town; Fil: Bradfield, Justin. University of the Witwatersrand; Sudáfrica Fil: Wadley, Lyn. University of the Witwatersrand; Sudáfrica

International audience; Here we provide a multiproxy record of climate change and human occupation at Wonderkrater, a spring and peat mound site situated in the interior of southern Africa. Recently extracted sediment cores yielded a number of Middle Stone Age (MSA) artefacts, prompting exploratory excavation of the sediments to understand better the geomorphology of the site, age of the sediments, cultural lithic sequence, vegetation and faunal remains, and to try to establish whether human use of the site was to some extent climatically driven. Excavations yielded late Pleistocene mammal fauna and flora, and three small MSA lithic assemblages with age estimates of 30 ka, >45 ka and 138.01 ± 7.7 ka. The upper layers comprise peat that preserves macrobotanical and faunal remains, implying local fen conditions in Acacia savanna woodland at 12 ka. Below the upper peat layers, a 1 m-thick layer of white sand yielded two MSA lithic assemblages in association with faunal remains dated to between 30.8 ± 0.7 ka and >45 ka. Clay underlying the sand has an OSL age of 63.1 ± 5.8 ka, and sandy peat below it has an Infrared Stimulated Luminescence (IRSL) age of 70 ± 10 ka. Faunal remains in the lower sand levels, and dental stable carbon isotope analysis of herbivores, indicate a substantial grassland component in the landscape during late MIS 3 (>45 ka). Charcoal, phytolith and pollen data show a change from moderately warm and dry grassy savanna woodland in the lower sand levels, to cooler and wetter grassland with woody shrubs in the uppermost levels by 30 ka. The conditions that resulted in the deposition of the sand also attracted people to the site, but whether it served as an oasis in an arid landscape, or was occupied during wet phases, is unclear. The composition of the lithic assemblages, which include many tools suitable for cutting, suggest that the peat mound may have been used as a place to harvest reeds, process plant materials and butcher animals that were either deliberately or accidentally trapped in mud or peat.