The long-term decline in terms of trade and the neolithisation of Northern Europe

While agriculture spread quite rapidly from the Levant to most parts of Europe during the sixth millennium, its adoption was delayed to the fourth millennium in Northern Europe, an area inhabited by complex hunter-gatherers (HGs) - mainly the Erteb�lle culture. This hiatus leads us to reject diffusion by migration or acculturation. It favours integrationist models of contact between foragers and farmers and attributes the shift to agriculture to social competition between HGs. We provide an alternative explanation of this shift, based on an economic mechanism related to trade between foragers and farmers. We demonstrate that the terms of trade of raw materials extracted and sold by foragers have a tendency to decline in the long term in relation to the food resources produced and sold by farmers. Neolithisation of Northern Europe can therefore be viewed as the outcome of a long-term process based on trade in which HGs voluntarily get involved without forecasting that it will, in the end, constrain most of them to give up their way of life. Such an explanation is consistent with the long period of contact between foragers and farmers provided by archaeological records and recent palaeogenetic studies.