Table 1.

Baseline assumptions

Item	Specification
Fertility	Ache, normalized to GRR = 1 (16); Elastm,γ = +1.0
Mortality	Initially 0 until 80, then 1.0; Elastasdr,γ = −1.0; ε = 0.005; δ = 0.1
Production	Average of three hunter–gatherer groups (22, 23); Elasty,γ in childhood = 0.5, in previous period (t − 1) = 0.5
Density dependence	Multiply production age schedule by (E/N)1.0, Elasty,(E/N) = 1.0
Consumption	Base = average of three hunter–gatherer groups (22, 23); Elastc,γ = 1.0
Mutation frequency	For each of 16 ages affected, 0.01 risk per birth.
Environment, E	Set for equilibrium population size near 100,000 or sometimes 10,000
Group formation	Fusion if falls below 8, fission if rises above 25, keep kin together at fission, families fuse randomly.
Food sharing	Families consume a specified share of their output e.g. 50% and share 50%; this share differs by simulation
Age and time	5-year age groups, 5-year time steps per cycle
Sequencing	γ Measured at end of age–time interval
	Deaths occur at end of interval
	Births occur after death at end of interval
Length of simulation	At least 15,000 cycles or 75,000 years; some up to 45,000 cycles