“…The meeting between small migrating groups (Manninen et al, 2021b) would have resulted in significant fitness benefits to increases in population size and densities (Allee and Bowen, 1932), all the while temperatures continuously rose, seasonality decreased (Figure 5) and the Fennoscandian ice-sheet continued to melt (Stroeven et al, 2016). Moreover, groups would have had the possibility to receive or imitate technological innovations such as the reduction of microblades from conical blade cores (Sørensen et al, 2013) or the slotted bone point (Manninen et al, 2021a) through increased inter-group contact (Damlien, 2015, 2016; Günther et al, 2018; Kashuba et al, 2019). Together, these new ideas would help prevent subsistence risk and allow access to new ecological niches, as testified in the use of the rock-shelter of Saevarhelleren (Bergsvik and David, 2015).…”