 40. A Geographical Perspective on Personality Traits 827
One example of how geographical differ -
ences in social norms could contribute to 
personality differences comes from research 
on cross-  national differences in personality 
development. Specifically, using a very large 
age- diversified sample, Bleidorn and col -
leagues investigated age trends in personal -
ity to determine whether the trajectories of 
personality development vary across coun -
tries as a function of certain societal norms, 
such as the timing of marriage, parenthood, 
and joining the labor force (Bleidorn et al., 
2013). The results revealed different age 
trends per country and suggested that so -
cial norms influenced personality develop -
ment. More specifically, in countries where 
financial independence and family forma -
tion began during late adolescence, levels of 
extraversion, agreeableness, conscientious -
ness and openness increased and levels of 
neuroticism decreased at an earlier stage 
compared to countries where the normative 
timing occurred later. These results not only 
reveal the impact that social norms can have 
on personality development, but they also 
indirectly support the claim that geographi -
cal variation in social norms can contribute 
to differences in personality traits.
Ecological  Influence
Features of the physical environment, such 
as temperature, precipitation, green space, 
pathogen prevalence, and population den -
sity, have direct effects on many aspects of 
people’s lives, which could affect the preva -
lence of certain personality traits. For exam -
ple, there is evidence that regional variation 
in personality is linked to average tempera -
ture (Wei et al., 2017). More specifically, 
data from two large samples in China and 
the United States indicated that agreeable -
ness, extraversion, and emotional stabil -
ity were higher in regions where the ambi -
ent temperature was pleasant (i.e., 22°C) 
compared to regions with colder or hotter 
ambient temperatures. These findings dem -
onstrate how features of the environment 
can influence social behavior and thence 
personality. Evidence from several studies 
in cultural and environmental psychology 
indicate that specific features of the natural 
and built environments have consequential 
outcomes for personality (Cutrona, Wallace, & Wesner, 2006; Fincher, Thornhill, Mur -
ray, & Schaller, 2008; Van de Vliert, 2013).
One example that demonstrates ecological 
influence comes from work by Talhelm and 
colleagues (2014) on the impact of subsis -
tence strategies on personality. Results from 
a large-scale study across China indicated 
that people from areas that have historically 
depended on rice farming were more per -
ceptually interdependent and holistic think -
ing compared to people from areas that de -
pended on wheat farming. The explanation 
is that different subsistence strategies en -
courage different styles of social interaction, 
with more cooperation and interdependence 
for rice farming compared to wheat farming. 
Research on regional variation in pathogen 
prevalence and personality provides another 
example of ecological influence (Schaller, 
2006; Schaller & Duncan, 2007; Schaller & 
Murray, 2008; van Leeuwen, Park, Koenig, 
& Graham, 2012). The results from a num -
ber of investigations strongly suggest that 
pathogen prevalence affects population-  level 
conscientiousness, extraversion, and open -
ness. The explanation is that survival in 
areas with large numbers of disease-  causing 
microorganisms required caution, prudence, 
and limited social contact with strangers.
Selective  Migration
Whereas social and ecological influences 
focus on how environmental factors can 
contribute to geographical personality dif -
ferences, selective migration focuses on the 
impact that people’s decisions about where 
to live can have on them. The idea comes 
from research on person–  environment in -
teractions, which indicates that individuals 
seek and create environments that satisfy 
and reinforce their needs (Buss, 1987; Sand -
strom, Lathia, Mascolo, & Rentfrow, 2017). 
Most of the research that supports such in -
teractionist theories defines environments in 
terms of living spaces, social relationships, 
or occupations. But what is the evidence that 
people choose places to live with the aim of 
satisfying their needs?
When choosing a place to live, there are 
several factors to consider: budget, size, dis -
tance to work, safety, proximity to family, 
schools, amenities, and a range of others. 
But not everyone applies the same weight 