We claim that the correlation of individualism with faster societal change results from a causative in
uence as
predicted by our model. Other factors such as income levels also correlate with individualism, and it's possible that
what we observe is ultimately also related to GDP or other variables. We certainly cannot exclude that there may be
other causative factors. For example, our model in its current form is incapable of explaining dierences in smoking
prevalence between genders and why these inter-gender dierences vary between countries [14]. Nevertheless, we
remark that many previously proposed causative factors for dierences in observed inter-country smoking dynamics
can be accounted for within our modelling framework. In particular, beliefs about the harmful eects of smoking, the
price of cigarettes, socioeconomic status and inequality, and government regulation have all been cited as potential
factors aecting the dierences observed in inter-country smoking dynamics [14]. Each of these factors can be
interpreted within our modelling framework. For example, beliefs about the harmful eects of smoking, as well
as the price of cigarettes, both likely contribute directly to individual utility derived from smoking (ux) and from
non-smoking (uy). Moreover, socioeconomic status may aect individual utility from smoking indirectly by aecting
an individual's tolerance for risk and/or how they discount future rewards and costs (i.e. how they discount their
future health status) [29]. Addressing the model's inability to account for gender dierences in smoking prevalence
and quantifying the relationship between other causative factors and model parameters are potential areas for future
work.