Cross-country relationships between life expectancy, intertemporal choice and age at first birth

Abstract

Humans, like other animals, typically discount the value of delayed rewards relative to those available in the present. From an evolutionary perspective, prioritising immediate rewards is a predictable response to high local mortality rates, as is an acceleration of reproductive scheduling. In a sample of 46 countries, we explored the cross-country relationships between average life expectancy, intertemporal choice, and women's age at first birth. We find that, across countries, lower life expectancy is associated with both a smaller percentage of people willing to wait for a larger but delayed reward, as well as a younger age at first birth. These results, which hold when controlling for region and economic pressures (GDP-per capita), dovetail with findings at the individual level to suggest that life expectancy is an important ecological predictor of both intertemporal and reproductive decision-making.

Young Children From Three Diverse Cultures Spontaneously and Consistently Prepare for Alternative Future Possibilities

“…Indeed, as has been found in studies of theory of mind development (e.g., Shahaeian, Peterson, Slaughter, & Wellman, 2011;Wellman, Fang, Liu, Zhu, & Liu, 2006), there may still be robust cultural variations in the steps that children acquire diverse instantiations of the capacity. To this end, future research may wish to investigate the crosscultural development of other future-oriented behaviors, such as tool acquisition and subsequent use (see Suddendorf, Nielsen, & Von Gehlen, 2011), acting for future desire states (see Atance & Meltzoff, 2006), intertemporal choice (see Bulley & Pepper, 2017;Metcalf & Atance, 2011;Mischel, Shoda, & Rodriguez, 1989), deliberate practice (see Brinums, Imuta, & Suddendorf, 2017), external reminder setting (see Redshaw, Vandersee, Bulley, & Gilbert, 2018), and affective forecasting (see Gautam, Bulley, von Hippel, & Suddendorf, 2017).…”

Environmental harshness is associated with lower investment in collective actions

“…For instance, it has been shown that women's age at first birth is younger when extrinsic mortality risks are higher (Low et al, 2008). One possible explanation for this acceleration of reproductive scheduling is that it offsets the fitness cost of high extrinsic mortality by increasing the chance of reproducing before death (Bulley & Pepper, 2017…”

“…Specifically, harsher ecologies tend to be associated with psychological traits such as an immediate reward orientation and a shorter time horizon (Bulley & Pepper, 2017;Griskevicius et al, 2011). One possible reason for this is that people living in harsher and unpredictable environments are less likely to reap the benefits of deferred rewards.…”

The appropriate response of Spanish Gitanos: short-run orientation beyond current socio-economic status

“…A recent study using survey data from more than 40 countries finds that the proportion of "impatient citizens" (i.e. those who chose the sooner-smaller reward in a single hypothetical survey question) in a country is negatively related to the country's average life expectancy, and that adding life expectancy to the equation eliminates the negative country-level relationship between impatience and age at first birth (Bulley & Pepper, 2017). The latter results, although not directly addressing causality due to the cross-sectional nature of the data, may suggest that it is environmental mortality cues (as proxied by life expectancy) that influence both short-run orientation and early-reproduction decisions.…”