A new experimental methodology for assessing adhesive properties shows that Neandertals used the most suitable material available

Proc. Natl. Acad. Sci. U.S.A.

et al. 2019

We report the discovery of a 50,000-y-old birch tar-hafted flint tool found off the present-day coastline of The Netherlands. The production of adhesives and multicomponent tools is considered complex technology and has a prominent place in discussions about the evolution of human behavior. This find provides evidence on the technological capabilities of Neandertals and illuminates the currently debated conditions under which these technologies could be maintained. 14C-accelerator mass spectrometry dating and the geological provenance of the artifact firmly associates it with a host of Middle Paleolithic stone tools and a Neandertal fossil. The find was analyzed using pyrolysis-gas chromatography-mass spectrometry, X-ray micro-computed tomography, and optical light microscopy. The object is a piece of birch tar, encompassing one-third of a flint flake. This find is from northwestern Europe and complements a small set of well-dated and chemically identified adhesives from Middle Paleolithic/Middle Stone Age contexts. Together with data from experiments and other Middle Paleolithic adhesives, it demonstrates that Neandertals mastered complex adhesive production strategies and composite tool use at the northern edge of their range. Thus, a large population size is not a necessary condition for complex behavior and technology. The mitigation of ecological risk, as demonstrated by the challenging conditions during Marine Isotope Stage 4 and 3, provides a better explanation for the transmission and maintenance of technological complexity.

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Section: Behavioral Implicationsmentioning

confidence: 99%

Middle Paleolithic complex technology and a Neandertal tar-backed tool from the Dutch North Sea

Niekus¹,

Proc. Natl. Acad. Sci. U.S.A.

et al. 2019

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“…Birch tar is a highly suitable material to haft stone tools with and may have been preferred because of its reusability, workability, and cohesive strength. Birch tar also has known antibacterial properties (Yogeeswari and Sriram 2005) and is more able to withstand both high-and low-frequency forces at a range of different temperatures (Kozowyk and Poulis 2019). These properties support the high preservation index of birch bark tar.…”

Section: Archaeological Comparisonsmentioning

confidence: 67%

“…Adhesives provide a unique window onto past technologies and human behaviour. The selection and use of different hafting materials may be the result of environmental constraints, production complexity, physical or material properties, the intended function, or possibly even sociocultural or economic factors (Berdan et al 2009;Kozowyk and Poulis 2019;Kozowyk et al 2017b;Wadley et al 2004). It is the variation in adhesive properties that can give so much information about the past that also directly affects how likely the materials are to survive to be analysed by archaeologists in the first place.…”

Section: Resultsmentioning

confidence: 99%

“…Flakes with a more uniform thickness are better suited to hafting, and the use of fire is a necessity for producing birch bark tar and mixing some compound adhesives (Kozowyk et al 2017b;Wadley 2005). Together, these technological changes go hand in hand with the development of adhesives and hafting and provided an advantage to the prehistoric users over simple single-component handheld tools and naturally weak or brittle adhesives such as pure pine resin (Barham 2013;Kozowyk and Poulis 2019). However, the direct correlation between adhesives and other contemporaneous technological advances is still unclear.…”

Section: Introductionmentioning

confidence: 99%

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Understanding preservation and identification biases of ancient adhesives through experimentation

Gijn

2020

Archaeol Anthropol Sci

Adhesive production is one of the earliest forms of transformative technology, predating ceramics and metallurgy by over 150,000 years. The study of the adhesives used by Neandertals and early modern humans currently plays a significant role in debates about human technological and cognitive evolution. Depending on the type of adhesive used, different production sequences were required. These can vary in complexity and would have needed different knowledge, expertise, and resources to manufacture. However, our knowledge of this important technological development is severely hampered by poorly understood taphonomic processes, which affects the preservation and identification of adhesive materials and leads to a research bias. Here we present the results from a 3-year field preservation experiment. Flint flakes hafted and non-hafted with replica adhesives were left to weather naturally on and below the surface at two locations with different soils and climatic conditions. Differential preservation was recorded on a variety of natural adhesives by digitally measuring the surface area of each residue before and after the elapsed time. Residues were further assessed and photographed using metallographic optical microscopy. Results show that certain adhesives preserve to a significantly higher degree than others, while some materials may be more easily overlooked or visually misdiagnosed. We must therefore be aware of both taphonomic and identification biases when discussing ancient adhesive technology. This research provides a first look that will help us understand the disparities between which adhesives were used in the past and what we find in the archaeological record today.

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“…The importance of uniform methods of analysis to establish diagnostic criteria for different production methods is also clear. Birch tar is well suited for reuse (9). However, curation similar to Neolithic finds (6) cannot be posited on current evidence and intuits a large amount of logistical complexity on the part of Neandertals.…”

Section: Compositionmentioning

confidence: 99%

Reply to Schmidt et al.: Interpretation of Paleolithic adhesive production: Combining experimental and paleoenvironmental information

Proc. Natl. Acad. Sci. U.S.A.

Dusseldorp

et al. 2020