From the paper:
The concordance of Bayesian linguistics with the pulse-pause archaeological model is remarkable. So, how was the slow-boat model supported in the first place?
The innovationist "pulse-pause" scenario posits that the Austronesians originated in Taiwan around 5500 years ago and spread through the Pacific in a sequence of expansion pulses and settlement pauses (2, 4–6).
The divergence time estimates for the age of the Austronesian language family support the pulse-pause scenario (Fig. 2). The estimated root age of Austronesian across all the post–burn-in trees has a mean of 5230 years [95% highest posterior density (HPD) interval, 4750 to 5800 years B.P.). The divergence time estimates were robust across a range of calibrations and different models (28).
In contrast, proponents of the slow-boat scenario argue that the Austronesians emerged from an extensive sociocultural network of maritime exchange in Wallacea (in the region of modern day Sulawesi and the Moluccas) around 13,000 to 17,000 years B.P. based on the dating of mitochondrial lineages (11, 12).The problem was that a calibrated evolutionary mutation rate was used to estimate these ages, making them about 3 times older than the Austronesian expansion. Sound familiar?
Our estimates for the age of the Austronesian expansion are considerably younger than the deep age estimates of the slow-boat scenario (11, 12, 15). One possibility is that these deep estimates are artifacts due to problems with accurately dating genetic change. There is increasing evidence that rates of genetic change estimated over thousands of years are substantially higher than the long-term substitution rate (21). This violation of the molecular clock leads to the systematic overestimation of recent divergence times.
Science DOI: 10.1126/science.1166858
Language Phylogenies Reveal Expansion Pulses and Pauses in Pacific Settlement
R. D. Gray et al.
Debates about human prehistory often center on the role that population expansions play in shaping biological and cultural diversity. Hypotheses on the origin of the Austronesian settlers of the Pacific are divided between a recent "pulse-pause" expansion from Taiwan and an older "slow-boat" diffusion from Wallacea. We used lexical data and Bayesian phylogenetic methods to construct a phylogeny of 400 languages. In agreement with the pulse-pause scenario, the language trees place the Austronesian origin in Taiwan approximately 5230 years ago and reveal a series of settlement pauses and expansion pulses linked to technological and social innovations. These results are robust to assumptions about the rooting and calibration of the trees and demonstrate the combined power of linguistic scholarship, database technologies, and computational phylogenetic methods for resolving questions about human prehistory.