Download Schizotypy, Creativity, and Mating Success in Humans

By Daniel Nettle and Helen Clegg
Presented by Grant and Brooke
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1% of the population
across cultures
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Heritable
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Drastically reduced
reproduction
Too frequent to be a
mutation
 Natural selection has
not eliminated
schizophrenia
 Is there a beneficial
effect of the traits?
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Continuum of personality experience ranging
from normal dissociative, imaginative states to
extreme states related to psychosis
 More schizotypy does not mean more ill
 Linked to academic achievement and creativity
 Negative effects may remain dormant unless
triggered by environment
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Traits measured on 4 dimensions
High scores predict the onset of
schizophrenia
Schizophrenic patients score high on all 4
dimensions
Bipolar patients score high on 3 dimensions
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High incidence of serious
psychiatric illness in
families of artists
Many studies found that
individuals active
in creative arts have
elevated levels of some
schizotypy traits
Is artistic creativity the
evolutionarily beneficial
effect of schizotypy?
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Geoffrey Miller’s hypothesis of costly displays
of quality whose function is to attract mates
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Prediction: artistic production correlated with
high number/quality of sexual partners
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Unusual experiences: magical
thinking/perceptual
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Cognitive disorganization: poor concentration
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Impulsive non-conformity: reckless behaviors
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Introvertive anhedonia: lack of
enjoyment/social withdrawal
Unusual experiences
and impulsive nonconformity elevated in
poets and artists
 Introvertive anhedonia
positively associated
with schizophrenia,
but negatively
associated with artistic
creativity
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Higher schizotypy traits of artists (unusual
experiences and impulsive non-conformity)
should increase number of sexual partners
Increase in sexual partners should operate
through artistic production
Schizotypy that is characteristic of
schizophrenics (introvertive anhedonia)
should be negatively correlated with mating
success
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Examines the relationship between
schizotypy and mating success
The sample looks at the general adult
population augmented by targeted sampling
of artists and poets
The sample is not representative of the
population; it is specifically designed to
produce a full range of schizotypy scores in a
non-clinical context
Unusual experiences contains items referring to
perceptual and cognitive aberrations and magical
thinking
 Cognitive disorganization describes difficulties of
attention and concentration
 Impulsive non-conformity refers to violent and
reckless behaviors
 Introvertive anhedonia measures lack of enjoyment
and social withdrawal
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Participants were 425 British adults (256 male, 269
female), average age of 40.5 years with standard
deviation of 14.5 years
Participants received a gift card for participation
Recruited people from the general population using
online advertisement, questionnaire packs, and
mature psychology students
Recruited specialist creative groups via advertisement
in visual art magazine, poetry website, and by writing
directly to published poets
100 more people heard about the study and indicated
their interest to participate
Participants filled out the O-LIFE schizotypy inventory
and a section on psychiatric history
 Also filled out a section regarding creative interests
and participants indicated their degree of creative
activity in poetry or visual art
 Participants rated selves as not producing poetry or
art (241), hobby producer (57), serious producer (60),
professional producer (67) in either domain
 A final section of the questionnaire contained wideranging personal history questions that asked for
information on mating success (reproductive success
was defined as greater number of partners)
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Are your thoughts sometimes so
strong you can almost hear
them?
Have you ever felt you have
special, almost magical powers?
Is your hearing sometimes so
sensitive that ordinary sounds
become uncomfortable?
Are you so good at controlling
others that it sometimes scares
you?
Does it often happen that nearly
every thought immediately and
automatically suggests an
enormous number of ideas?
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Do you ever have the
urge to break or smash
things?
Do you often feel like
doing the opposite of
what people suggest,
even though you know
they are right?
Would you take drugs
which may have strange
or dangerous effects?
Have you ever taken
advantage of anyone?
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Do you find it difficult
to feel very close to your
friends?
Are you much too
independent to really get
involved with people?
Are people usually better
off if they stay aloof from
emotional involvements
with people?
Do you have trouble
letting yourself go and
enjoying yourself at a lively
party?
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Are you sometimes so
nervous that you are
blocked?
Do you ever feel that your
speech is difficult to
understand because the
words are all mixed up?
No matter how hard you try
to concentrate do unrelated
thoughts always creep into
your mind?
Do you often feel "fed up"?
Are you easily hurt when
people find fault with you or
the work you do?
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Multiple regression analysis
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Independent variables: 4 dimensions, age,
sex, social class
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Dependent variable: number of partners
Results
PREDICTION: If
schizotypy increased
mating success, it would
do so through
enhancing creative
behavior
RESULTS: Number of
partners and level of
engagement with
poetry and visual arts
Results
PATH ANALYSIS
Linkages among
creative behavior,
mating success and 3
dimensions
Cognitive
disorganization left
out because no
significant
relationship with
creative activity or
mating success
The results are consistent with Miller’s
hypothesis that artistic creativity functions as a
mating display
 Schizophrenia patients are also high in unusual
experiences and impulsive non-conformity
 These results are consistent with the view that
schizotypal traits are maintaied in the human
population at significant levels because the
negative effects of psychosis are offset by
enhanced mating success
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Impulsive nonconformity can
enhance mating
success due to the
reckless behavior
(direct benefit)
 Unusual experiences
can manifest as
enhanced creativity
(indirect benefit)
Mating Success
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Schizotypal Traits
But recent evidence suggests a
different model…
Poets and artists score as
highly on unusual
experiences and impulsive
non-conformity as
schizophrenic patients do
 The difference is that poets
and artists do not score as
high on the introvertive
anhedonia
 Suggests that individuals in
good condition can channel
odd experiences and
impulses into creative output
and adaptive behaviors, while
those in poor condition
develop psychiatric disorders
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Introvertive anhedonia
appears to be the critical
condition-related
dimension that
differentiates between
the positive and
negative sequelae of
schizotypal traits
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There were no observed sex differences in the
relationships between creative output and
reproductive success
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Results show that when either sex invests in
creative output, it has similar effects on
mating success
Mate choice is
linked to creativity,
creativity to
schizotypy, and
schizotypy to
schizophrenia
Measurement of mating success is number of
partners
 Never look at quality of partners
 Present day results may not relate to EEA
 Pattern is the same for male and female artists,
counter to condition dependent fitness
hypothesis
 Quality of creative work produced never
assessed
 People may misrepresent how often they
produce creative work
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