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54 A. C. Ciani and C. Capiluppi
new approach, initially developed to study sexual orientation
(Camperio Ciani, Corna, & Capiluppi, 2004), consisting of
comparing small isolated populations with a reference
population which shares a common historical, linguistic and
cultural context. In a population survey conducted in three
Italian archipelagos they found significant differences
between islander and mainlander personality traits on a
Big Five scale (Costa & McCrae, 1992; Goldberg, 1990;
McCrae & Costa, 1999) based on the adjectives question-
naire validated for Italian language (Perugini & Di Blas,
2002; Perugini & Leone, 1994; Piconi, 1998). The emerging
islander personality profile was characterized by lower
extraversion and openness to experience, and more
conscientiousness and emotional stability than in the
mainland inhabitants: they suggested these personality
differences could represent traits which result in better
adaptation to the island environment. Immigrants to the
islands (who had been resident for at least 20 years) were
significantly more extraverted and more open to experience
than original islanders, that is they retained a mainlander
profile despite long-lasting permanence in the insular
environment, which led the authors to suspect the presence
of a genetic influence on personality, however, the study
could not definitely exclude that behaviours learned during
childhood were retained in adulthood. Emigrant islanders
were found to be more open to experience and more
extraverted than sedentary islanders. Camperio Ciani et al.
(2007) suggested gene flow as the possible genetic selection
mechanism (Bodmer & Cavalli-Sforza, 1976; Camperio
Ciani, Stanyon, Scheffrahn, & Sampurno, 1989), that is the
voluntary emigration of fertile individuals who were, in this
case, higher in extraversion and openess to experience.
The purpose of this study is firstly to assess whether the
personality trait differences between islanders and main-
landers reported in Camperio Ciani et al. (2007; Camperio
Ciani & Ceccarini, 2002) can be detected in a different
archipelago with similar socio-ecological conditions to
previously studied islands.
Hence, we try to answer the following three questions:
1. Are there differences in personality traits between
islanders and mainlanders?
2. Can these differences be ascribed to stable traits of
genetic origin, or are they due to individual flexible
adaptation to the environment?
3. Which mechanism could account for the origin of these
differences?
Van Oers proposed the ‘founder effect’ (Van Oers, 2007) as
a further explanation of genetic mechanism to explain how
these personality differences come about. The founder effect is
by definition a chance effect (non-adaptive) (Bodmer & Cavalli-
Sforza, 1976), hence if the same results can be found in a novel
archipelago, this alternative hypothesis would be less likely.
A further alternative to the genetic explanation of the
personality differences suggested by Camperio Ciani et al. is
the influence of early experience. According to the Big Five
paradigm, the first years of life might contribute to the shaping
of the definitive personality profile (Costa & McCrae, 1992;
McCrae & Costa, 1999). The role of the environment could
Copyright # 2010 John Wiley & Sons, Ltd.
influence individuals through early experiences during infancy
(Forgas & Van Heck, 1992), given that most immigrants lived
their childhood on the mainland. To address this alternative
Early Experiences hypothesis, we studied the immigrant
subjects in greater depth. Finally, we discuss whether a general
explanation for such a rapid and significant personality
divergence in small isolated environments can be derived and
then extended to similar contexts.
For each question we present arguments based on
empirical evidence by comparing the relevant sample subsets
of the population under investigation.
METHODS
Population under investigation
We selected the Egadi archipelago, the southernmost set of
islands off the coast of western Sicily because it has similar
linguistic and socio-ecological conditions to those of the
previous study, and we had access to all the relevant historical
and geographical details required to test our hypothesis.
The Egadiislands (Favignana, Levanzo and Marettimo
and a few other islets) constitute the southernmost Italian
archipelago, 15–30 sea miles off the western shore of Sicily
where the town of Trapani is situated. The total population in
the Egadi archipelago is at present 4394, of which 220 are
resident in Levanzo Island, 450 in Marettimo Island and the
rest in Favignana Island. Only 50% of those who are listed as
resident are actually living on the island, the remaining 50%
are listed as being resident but have, in fact, emigrated. These
islands fulfil the requisites of the long-lasting isolation
required to highlight the hypothesized effect of the adaptive
selection for personality traits. Even if the archipelago is now
a tourist destination, during the last 400 years these islands
have experienced limited immigration, a fact confirmed by
surname analysis and by studies of birth, marriage and death
registries (Veronese, 2003). This means that for at least 20–
25 generations the small village communities did not mix
extensively with the mainland population.
In order to allow a detailed comparison with the study by
Camperio Ciani et al. (2007), the same criteria were used to
identify the specific control population. The population of
the whole of Italy is not adequate because Italy is a highly
fractioned country in terms of regional culture, dialects and
traditions. To account for such variables the closest coastal
land to the Egadi was selected as the control population, in
the region of Trapani (Sicily), which shares the same culture,
language and latitude. This control population, composed of
people from both urban and rural areas, is defined as
Mainlanders and is used as the reference group to which all
other populations are compared. Naturally this control
population has also its limits due to its limited geographic
distribution and different history from the archipelago.
Historical account
Cave graffiti show that the Egadi Islands have been populated
since the Paleolithic era and since then a multitude of
Eur. J. Pers. 25: 53–64 (2011)
DOI: 10.1002/per