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Personality differences in small island populations 59

Table 3. Genetic and environmental hypotheses

Subsets comparison N Extra Agreeable Conscient Emotional Openness to
version ness iousness stability experience

GENETIC HYPOTHESIS 30 þ8.60 À1.25 S4.51 À0.22 þ4.11
NATIVE IMMIGRANTS 380 0.000 0.513 0.004 0.903 0.020
NATIVE ANCIENT ORIGIN ISLANDERS 28
ADAPTED IMMIGRANTS 28 þ7.36 þ1.70 þ0.97 þ3.09 þ3.14
NOT NATIVE ANCIENT ORIGIN ISLANDERS 116 0.026 0.581 0.695 0.222 0.317
NATIVE MIXED ORIGIN ISLANDERS 380
NATIVE ANCIENT ORIGIN ISLANDERS þ3.99 À1.27 À1.00 S3.08 þ0.22
0.001 0.232 0.243 0.003 0.826

Environmental hypothesis þ2.31 þ0.76 þ4.90 þ1.15
0.290 0.727 0.025 0.604
ADAPTED IMMIGRANTS 28 À0.10
À0.97 À2.54 þ1.35 À2.81
MAINLANDERS 106 0.965 0.638 0.215 0.489 0.133

NATIVE IMMIGRANTS 30 À2.02 À1.82 À1.26 À2.57 À3.60
0.476 0.662 0.284 0.177
MAINLANDERS 106 0.291
þ0.46 þ2.37 þ2.56 S5.32
NATIVE IMMIGRANTS 30 À2.23 0.762 0.054 0.088 0.000

ADAPTED IMMIGRANTS 28 0.387 þ0.88 þ3.17 þ1.17 S4.42
0.662 0.044 0.531 0.018
NATIVE ISLANDERS 496 À0.55

NOT NATIVE ISLANDERS 47 0.754

NATIVE ANCIENT ORIGIN ISLANDERS 380 À1.50

NOT NATIVE ANCIENT ORIGIN ISLANDERS 28 0.675

For each comparison, the T-score difference estimated by the ANCOVA model with age, gender and education as covariates is reported in order to evaluate the
effect size, followed by the significance of the difference p-values.
Bold value signify the comparisons between two different populations

native ancient origin islanders (n ¼ 380), both of them Third question. Which mechanism could be at the
sharing the same island environment but different genetic origin of these differences?
ancestry, we found the former significantly more extraverted
(þ4.0 T-scores, p ¼ .001) and less emotionally stable (À3.1 In order to investigate if emigration was at the origin of such
T-scores, p ¼ .003). differences, we examined all islanders (native and non-
native, n ¼ 543) subdivided, in Table 2, into those who
In the second part of Table 3, the first ‘environmental’ emigrated during their own lifetime from the island
comparison measures the effect of living for a long time in the (n ¼ 167) and those who never left the island (n ¼ 376).
insular environment on the adapted immigrants, the second Islanders who emigrated from the islands are significantly
one shows the effect on the native immigrants of living on the more extraverted ( p ¼ .001) and more open to experience
islands since birth, the additional three comparisons test the ( p < .001) than the sedentary (non-emigrated) insular
influence of the infancy environment on immigrant and population (þ3.7 and þ4.0 T-scores, respectively). In
islander personality, the so-called Early Experience hypoth- Figure 5 we show the corrected T-scores of emigrants
esis. In this case, comparing adapted immigrants and versus sedentary, referred to average T-scores of main-
mainlanders, who belong to the same mainland population landers, which is always 50. It can be noted that emigrants
but did not share the same environment for a long time, we are significantly more extravert and Open to experience than
found that the former show no differences from mainlanders sedentary islander but, as all other islanders, they are
for all traits except for higher emotional stability (þ4.9 T- significantly less extravert and open to experience than
scores, p ¼ .025). Comparing native immigrants and main- mainlanders. We then restricted the comparison to the subset
landers, who did not share the same environment since birth, of native islanders only (n ¼ 496, Table 2), to exclude the
we found that native immigrants do not differ from the possible confounding effect of individuals not born on the
mainland population on any personality traits. Comparing island, and we obtained the same results.
native immigrants and adapted immigrants, the former differ
for having had their early experience on the island: we found DISCUSSION
that native immigrants show no differences from adapted
immigrants on any personality traits. In a comparison of native The results of our study shown in Table 2 parallel previous
islanders and non-native islanders, the former differs for findings from the study of other Italian archipelagos
having had early experience on the island: we found that (Camperio Ciani and Ceccarini, 2002; Camperio Ciani
native islanders are less open to experience (À5.3 T-scores, et al., 2007). Islanders are always significantly less extra-
p < .001) and possibly more conscientious (þ2.4 T-scores, verted and open to experience than mainlanders. We have
p ¼ .054) than non-native islanders. Finally, when comparing shown that subjects who immigrated to the islands retain a
native ancient origin islanders and non-native ancient origin personality profile, which is undistinguishable from the
islanders, the former differs in that that have had early mainland population, except for higher emotional stability;
experience on the island: we found that native ancient origin in contrast, immigrants are more extraverted and more open
islanders are less open to experience (À4.4 T-scores, to experience than islanders. These results are more
p ¼ .018) and more conscientious (þ3.2 T-scores,
p ¼ .044) than ancient origin islanders born on the mainland.

Copyright # 2010 John Wiley & Sons, Ltd. Eur. J. Pers. 25: 53–64 (2011)
DOI: 10.1002/per